Wisconsin Nutrition Seminars
Health and Performance Concerns for Athletes
Resources in Sports Nutrition .................................................................................................................... 2
Nutrient deficiency ....................................................................................................................................... 2
Endurance .................................................................................................................................................... 4
Strength, Speed, Body Composition ........................................................................................................ 6
Exercise recovery........................................................................................................................................ 9
Immune system protection.......................................................................................................................... 9
Dietary practices and supplements with unproved benefits ................................................................... 9
Recent Sports Nutrition Abstracts
Nutrient Deficiency .................................................................................................................................... 10
Endurance Nutrition..................................................................................................................................... 9
Strength, Speed, Body Composition ...................................................................................................... 11
Other Nutrients and Supplements ............................................................................................................ 24
Wisconsin Nutrition Seminars Resources in Sports Nutrition / Page 1
Health and Performance Concerns for Athletes
Resources in Sports Nutrition presence of disordered eating is not necessary when energy
output is high enough. Bone loss increases both long-term
(osteoporosis) and short-term (stress fractures) risks. Use of
American College of Sports Medicine position stands:
oral contraceptives and calcium supplements provides some
protection, but not enough to stop bone loss.
Recommendation: Screen athletes for irregular menstrual
Healthnotes: available at several websites, including
function, low energy availability (urinary ketones is the only
practical tool), other bone loss risk factors, and (in high-risk
patients) low bone density. Assessment tools: menstrual
Australian Institute of Sport Nutrition Department:
history, bone densitometry, bone loss risk factor
Gatorade Sports Science Institute: http://www.gssiweb.com
A diet that has variety and consists of healthful foods should
be adequate for providing enough energy, protein, vitamins,
minerals, and other important nutrients. Restricted or unusual
diets may increase the risk of deficiency.
Recommendation: Choose daily from each important food
Nutrient deficiency group – including whole grains, lean proteins, fruits,
vegetables, and calcium sources. Assessment tool: Diet
Many nutritional deficiencies can impair health and/or athletic Quality Questionnaire.
performance. Most athletes with normal eating habits will not
develop deficiencies, but those who restrict their calories, or Multiple vitamin-mineral supplements**
those following unusual diets may be at risk. Disordered While many athletes do not need them, these supplements are
eating is especially common in sports having weight good insurance against possible inadequacies in the diet.
categories (e.g. wrestling, boxing), sports that favor small
body size (e.g. gymnastics, distance running, ski jumping), or Iron**
sports that may require a specific socially accepted body Some athletes, especially female endurance athletes are at risk
shape (such as figure skating). of iron deficiency, which can affect performance, even before
laboratory evidence of anemia is present. However, the
Adequate calories** presence of anemia is not a clear indication of iron deficiency,
Many athletes can provide themselves with adequate calories since some athletes develop a pseudoanemia that does not
by simply following normal eating habits and responding to require treatment and will not respond to iron
their appetite. However, athletes with prolonged and intense supplementation. Specific tests for iron deficiency are needed
training regimens may find it difficult to maintain weight and to identify candidates for supplementation.
stamina unless they give special attention to consuming
enough calories. Warning signs of inadequate calories can Recommendation: Screen athletes complaining of fatigue or
include chronic fatigue, sleep disturbances, reduced reduced performance with tests for iron deficiency. Treat
performance, impaired ability for intensive training, and deficiency with at least 100mg/day iron until serum ferritin
increased vulnerability to injury. normalizes. Emphasize good dietary iron sources such as lean
meats and iron-fortified foods, and use beverages with meals
Recommendation: Adequate calories to maintain appropriate that enhance iron absorption (citrus juices and others high in
body weight, body composition, training capacity, muscle vitamin C) rather than those than inhibit iron absorption
growth in strength athletes and, for women, to maintain (coffee, tea, red wine) Assessment tools: serum ferritin, diet
normal menstrual function. Assessment tools: diet analysis, analysis.
menstrual history, bone densitometry by DEXA or ultrasound
Female Athlete Triad Exercise increases zinc losses, and athletes with suboptimal
Recently re-characterized as 1) low energy availability, 2) diets may be at risk of deficiency, which could affect athletic
irregular menstrual function, and 3) bone loss.** Low energy performance.
availability affects estrogen and other metabolic hormones
that govern bone resorption and formation. Athletes are more Recommendation: multiple vitamin-mineral supplements used
prone due to higher energy output than non-athletes, and the by athletes to insure against dietary inadequacies should
Health and Performance Concerns for Athletes Resources in Sports Nutrition / Page 2
contain zinc, balanced with copper in an approximately 10-20 Fluids and electrolytes
to 1 ratio. Dehydration during exercise impairs performance, is a
common cause of muscle cramping, and increases health risks.
Some athletes are naturally more susceptible to dehydration,
and sports demanding optimal endurance and/or
cognitive/mental performance will be most affected. Risk
Purposeful dehydration in weight-class sports
Prolonged daily training or twice a day training
Use of diuretic medications
Athletes should plan to consume fluids before, during, and
after prolonged exercise to prevent the detrimental effects of
dehydration, especially when extreme climate conditions exist.
Plain water is sufficient to maintain and replace fluids in most
typical exercise situations, but flavored drinks containing
electrolytes may help some athletes drink more frequently and
in larger amounts.
Several hours of exercise in warm and/or humid conditions
may result in significant depletion of sodium and other
electrolytes in some athletes, which could reduce performance
and even pose serious health risks in some athletes. However,
less extreme exercise efforts and conditions do not require
electrolyte replacement, although the presence of electrolytes
in fluids may improve drinking habits during exercise as
Some endurance athletes are susceptible to hyponatremia, a
potentially serious complication. Hyponatremia most often
occurs by overdrinking during prolonged exercise (over four
hours). Athletes who gain weight during endurance exercise
should consider modifying their fluid and sodium intake to
prevent this weight gain in the future.1
Prehydration. Allow 8-12 hours between intense exercise
sessions and drink beverages with meals to promote normal
hydration. Consume 1-2 cups of fluids four hours before
exercise, and again two hours before if urine is dark.
Consuming sodium in food and fluids will stimulate thirst
and improve fluid retention.
During exercise. Athletes should develop customized
fluid replacement programs to prevent dehydration in
excess of 2% of body weight. This may require trial and
error due to wide variations in individual physiologies, as
well as differing exercise intensities and climactic
conditions. One to three cups of fluid per hour (depending
Consensus Statement of the 1st International Exercise-Associated
Hyponatremia Consensus Development Conference, Cape T own,
South Africa 2005. Free at
00002.pdf;jsessionid=Gh2dfBbmqMDQg59LGJ3VhGBT JQqT NmGhR5g
Health and Performance Concerns for Athletes Nutrient deficiency / Page 2
on body weight and exercise intensity) is typical of A refractometer is the most reliable instrument, but
requirements for endurance exercise, but extra caution is reagent strips or hydrometers may be suitable for screening
needed when continuous exercise is likely to last beyond purposes. Use first morning urine samples
three hours. Use of electrolyte-containing sports drinks Normal hydration = < 1.020 g/ml
during ultraendurance may help delay hyponatremia in
susceptible individuals. General recommendations for
electrolyte content is 20-30 mEq/L sodium (110-165 mg per 8
oz.) and 2-5 mEq/L potassium (20-50 mg per 8 oz.), but more
may be needed by some.
Rehydration. Post-exercise rehydration should be done
with a volume equivalent to 150% of weight lost (each
pound 24 ounces, each kilogram 1.5 liters), plus extra
sodium to improve retention. When dehydration is
moderate to severe, using fluids containing 50-80 mEq/L
sodium (275-440 mg per 8 oz.) is recommended. One
teaspoon of sodium chloride provides approximately 100
mEq of sodium.
Com parison of Electrolyte Content and Cost of Com m on
Electrolyte Supplem ents
Per Capsule Ave
Sodium Potassiu Magnesium Calcium cost per
Product (mg) m (mg) (mg) (mg) capsule
220 63 8 16
eload Zone TM 43 14 9 5 $ 0.16
Endurolytes 40 25 25 50 $ 0.16
Lava Salts 158 16 1 0 $ 0.15
SaltStick Caps 215 63 11 22 $ 0.18
Succeed 341 21 0 0 $ 0.12
Sustain 86 8 0 0 $ 0.12
T hermolyte 150 43 6 13 $ 0.14
T hermotabs 180 15 0 0 $ 0.07
Numbers represent milligrams per capsule or tablet
Sweat loss is average salt loss per 11oz/315mL of sweat for the average
athlete. Sweat losses can reach 0.5-2.0 liters/hr depending on conditions
Assessment tool: Weight changes
Regular practice of first morning body weight
measurement after urination can be used to establish a
baseline for evaluating fluid balance.
Weighing the dry, nude body before and after exercise
will indicate whether fluids have been adequately
consumed during exercise and may reveal weight gain that
may be associated with hyponatremia.
Variations of one percent of body weight as a result of
exercise are within normal limits; outside of these limits,
fluid use habits and risk factors for
dehydration/hyponatremia should be reevaluated.
Assessment tool: Urine specific gravity
Improves reliability when used along with weight
Health and Performance Concerns for Athletes Nutrient deficiency / Page 3
Endurance a minority of athletes. Some trials have shown that pre-event
meals or carbohydrate supplements that are low in GI result in
better performance compared to high GI meals and
High carbohydrate diet
supplements, but most studies have not found significant
Optimum glycogen stores are essential for optimal endurance
performance and maintaining intense training regimens . Diet
must supply carbohydrate for basic body functions, exercise
Recommendation: Athlete may choose to experiment with pre-
demands, and glycogen recovery. Mental skills used in some
event meals containing legumes, oats, or other low GI foods,
sports require adequate availability of glucose in the brain.
or carbohydrate supplements high in fructose, and evaluate
the effects on their performance. Ideally, such meals will
Recommendation: 7-12 grams of carbohydrates per kg body
provide 200-300 grams carbohydrate and will be consumed
weight (3.2-5.5 g/lb) on days prior to and following hard
three to four hours before exercise to allow for adequate
training or endurance competition, 5-7 grams/kg/day (2.3-3.2
digestion before the event. In cases of early morning events,
g/lb) prior to moderate or easy training, as much as possible
pre-event meals may need to be lighter, and greater attention
from whole grains, starchy vegetables, and fruits.
paid to consuming carbohydrate during exercise.
This pre-event strategy improves performance for some
endurance athletes, especially when continuous exercise lasts
over 90 minutes, and/or the athlete has not been maintaining
an adequate carbohydrate intake.**
Recommendation: choose one of the following regimens
Consume a high carbohydrate diet (10 grams/day per kg
body weight) for three to five days prior to event while
gradually reducing training time, ending with a day of no
Perform exhaustive exercise followed by 1-2 days of rest
and a high carbohydrate diet prior to event.
Carbohydrate supplementation during exercise
Preventing depletion of available carbohydrate during
exercise improves endurance performance. Sports drinks, gels,
or solid foods may each be appropriate according to the
nature of the exercise and individual preference. Mixtures of
sugar molecules using different absorption pathways
(glucose and fructose) may be most efficient, but high
fructose content may be undesirable due to slower absorption
causing gastrointestinal distress.**
Recommendation: For exercise lasting one hour or more,
consume 0.7 grams carbohydrate/kg body weight per hour
(typically 30-60 grams of carbohydrate per hour). Use of
sports drinks to replace both fluids and carbohydrate should
employ beverages containing no more than 8% carbohydrate
in order that fluid absorption is not compromised.
Carbohydrate replacement for glycogen recovery
After intensive training or competition, carbohydrate reserves
must be restored in time for the next exercise period. High
carbohydrate meals or high-density carbohydrate replacement
High carbohydrate meals on the day of competition generally
beverages are needed as soon as possible after exercise, when
improve endurance performance by increasing liver and
the window of opportunity is open for rapid glycogen
muscle glycogen prior to exercise, and providing a residual
resynthesis.** Beverages may be helpful for replacing fluids
source of carbohydrate from the digestive tract during
as well. Moderate to high GI foods and supplements may be
exercise.** However, high glycemic index (GI) carbohydrate
more helpful for quickly restoring glycogen stores. Glucose
consumed within one hour of exercise could lead to episodes
and sucrose are more effective than is fructose for supporting
of hypoglycemia during exercise and impaired performance in
post-exercise glycogen synthesis. Whether adding protein or
Health and Performance Concerns for Athletes Endurance / Page 4
amino acids to a carbohydrate replacement regimen improves resulting from increased fluid retention in the muscle tissues
recovery is unclear. of creatine users.
Recommendation: When exercise sessions are exhaus tive and
frequent, 1-1.2 grams carbohydrate per kilogram body weight Recommendation: consider creatine supplementation for non -
(~0.5 g per lb) should be consumed immediately following weightbearing endurance exercise only. See Strength and
exercise and repeated every hour for at least four hours. The Speed for protocol and cautions.
benefits of adding protein to glycogen recovery regimens is
controversial, but it does no harm. Caffeine
Caffeine stimulates the mobilization of fatty acids, which may
help delay depletion of glycogen stores during exhaustive
endurance exercise. Intense exercise lasting at least 30
minutes appears to benefit from caffeine in many athletes.**
Caffeine tablets may be more reliable than consuming coffee.
Caffeine has been banned as a performance-enhancing drug
above certain levels in the past, but is not currently banned.
Recommendation: caffeine tablets containing 3-6 mg/kg body
weight (1.4-2.7 mg/lb) taken one hour before exercise. This is
equivalent to 1-3 cups of brewed coffee.
Cautions: may increase the need to urinate during exercise
and can cause insomnia. High amounts can cause nausea,
heart palpitations, headache, and muscle tension.
One family of constituents in ginseng, the ginsenosides, has
been shown in animal studies to protect against various types
of stress and enhance physical performance. There is
extensive human research on the potential exercise
performance benefits of Asian ginseng (Panax ginseng), but
many studies were poorly designed and results are
conflicting. Beneficial effects may require larger amounts for a
prolonged period of time.
Recommendations: consider an 8-12 week trial of 2 grams/day
of powdered root or 200-400 mg/day of an extract standardized
for at least 4% ginsenosides.
Cautions: large amounts may cause insomnia or other
symptoms of overstimulation. Combining ginseng with
caffeine increases risk of overstimulation and may cause
Protein** gastrointestinal upset. Patients with hypertension or prone
Regularly active endurance athletes require an additional 50- to hypoglycemia should use ginseng with caution.
75% more protein than indicated by the Recommended
Dietary Allowances. However, typical Western diets already
provide this extra amount of protein when calorie intake is
Recommendation: 1.2-1.4 grams/day per kg body weight,
which should require no more than 10-15% of calories as
Endurance exercise performance is not typically enhanced by
creatine supplementation, except perhaps non-weight bearing
exercise such as cycling. This may be due to weight increases
Health and Performance Concerns for Athletes Endurance / Page 5
Strength, Speed, Body Composition Some research supports the use of protein or essential amino
acids and carbohydrate supplements prior to and/or
immediately following strength training, in order to increase
protein synthesis and reduce protein degradation, but
Muscle protein synthesis increases with strength training, but
whether muscle hypertrophy results from this effect is
if calories are increased from any source, protein may not
need to be emphasized to support muscle synthesis because
protein utilization becomes more efficient with strength
Recommendation: 6 grams essential amino acids plus 35 grams
training and less protein is burned for energy when calories
sucrose immediately before and/or following exercise. Other
are increased. Still, some authorities estimate that regularly
successful protocols have used 10-20 grams of protein plus a
active strength training athletes require an additional 100-
similar amount of carbohydrate. Milk has been shown to be a
125% more protein than indicated by the Recommended
suitable source in some studies.
Dietary Allowances. However, typical Western diets already
provide this extra amount of protein when calorie intake is at
or above levels adequate to support regular, intense training
Intense strength training requires enough carbohydrate to
regimens (e.g. when calorie intake is doubled using typical
replace muscle glycogen stores. Many athletes combine
foods, protein intake is also doubled).**
strength and endurance training which will further raise
Most controlled trials of protein supplements have not sho wn
any benefit to strength or body composition compared to
Recommendations: Some authorities recommend 5-6 grams/kg
placebo supplements of equal calorie value, unless those
body weight per day or 55-60% of calories as carbohydrate
supplements are used immediately before or after strength
when strength training is the primary activity. When exercise
training. Therefore timing of protein ingestion may be more
recovery time is short, restoring muscle glycogen may be
important than ingesting large quantities per day (see below).
improved by carbohydrate replacement protocols similar to
those recommended above for endurance exercise.
High protein intake, especially when using protein
supplements, probably does no harm, since theoretical
concerns about adverse effects to kidney or bone health have
Whey protein is a high-quality protein derived from milk,
not been seen in short-term studies of up to 2.0 grams/day per
where it accounts for 20% of the protein content. Studies
kg body weight in athletes. The most likely adverse
demonstrating benefits of increased protein consumption
consequences of high protein diets may be inadequate
before or after exercise have frequently employed whey
carbohydrate intake to support intensive training, increased
protein, but few studies exist comparing the effects of whey
intake of unhealthy fats from animal foods , or increased body
versus other protein sources such as casein and soy. Existing
fat if overall calorie intake is above individual requirements .
comparison studies disagree about whether whey is superior,
equivalent, or inferior to other protein sources as an anabolic
Recommendation: 1.6-1.8 grams/day per kg body weight (0.7-
0.8 grams/day per lb), which should require no more than 10-
15% of calories as protein. However, when calorie intake is
Recommendations: consider a trial of 1.2 grams/day per kg
restricted in order to reduce body fat, protein intake should be
body weight in combination with strength training,
up to 25-30% of calories. Monitoring body composition will
emphasizing use immediately before and/or after resistance
ensure weight gain is primarily lean body mass. Assessment
tools: hydrodensitometry, bioelectric impedence analysis,
Creatine is a precursor to phosphocreatine, which supports
ATP resynthesis during and after anaerobic exercise. Creatine
supplementation successfully increases muscle creatine
content in about 70% of the population. Muscle glycogen
storage may also be enhanced by creatine loading. In
responders, creatine supplementation consistently improves
performance of intense exercise lasting under 30 seconds (e.g.
sprinting, weight-lifting, sports involving intermittent
demands on speed or power) and improves repeated
performance after short recovery periods . Continuous, high-
intensity exercise lasting 30 seconds or longer may also
benefit from creatine, but relevant research is not as extensive
Pre- and post-workout supplements or consistent. There is also less extensive and consistent
Health and Performance Concerns for Athletes Strength, Speed, Body Composition / Page 6
evidence demonstrating benefits of long-term creatine trained athletes, but in untrained people combining HMB with
supplementation (beyond one week).** an exercise program has improved body composition or
muscle growth in two of three controlled studies.
Most short and long-term controlled trials have found that
creatine supplementation increases lean body mass, fat-free Recommendations: 37 mg/day per kg body weight (17 mg/day
mass, or muscle size when combined with a strength training per lb) or an average of 3 grams/day
program. The effects of creatine are probably a combination of
increasing water content of muscle and facilitating greater Cautions: none
strength training efforts. The increased body weight resulting
from creatine loading may be detrimental in sports favoring Pyruvate
lower weight (e.g. weight-bearing endurance running**) or in Pyruvate is a product of the glycolytic pathway. Pyruvate
sports involving weight divisions. may improve the results of an exercise program in untrained
individuals. Specifically, increased losses of weight and body
Recommendations: Loading phase: 300 mg/day per kg body fat have been demonstrated. Results in trained athletes have
weight (136 mg/day per lb) or 15-25 grams per day for 5-6 been disappointing.
days. Maintenance phase: 2-5 grams per day. Absorption is
enhanced when creatine is taken with 50-100 grams Recommendations: 6-10 grams per day in combination with an
carbohydrate per dose. exercise program.
Cautions: may cause gastrointestinal upset or muscle Cautions: may lower HDL levels; large amounts may cause
cramping in some people. While no adverse effects on renal gastrointestinal upset.
function have been seen in healthy people with up to five
years of supplementation, people with existing kidney Asian ginseng
disease should not take creatine. Most controlled trials have not found ginseng helpful for
enhancing short-term, intense exercise. However, one
Ribose controlled study reported increased muscle strength with
Ribose is the 5-carbon sugar synthesize in the pentose ginseng supplementation.
phosphate pathway that is used in the synthesis of
adenosine, which in turn is phosphorylated to ATP. Recent Recommendation: consider a six-week trial of at least 1
development of a ribose supplement has stimulated interest in gram/day powdered root or equivalent.
research into whether ribose can increase ATP resynthesis.
While research in cardiac muscle rehabilitation and Cautions: see Endurance
individuals with genetic disorders of ribose synthesis is
promising, several studies involving weight training or DHEA
repetitive sprint cycling have yielded disappointing results . Dehydroepiandrosterone (DHEA) is produced by the adrenal
glands and is a precursor to testosterone. While ineffective in
Alkalizing agents women or younger men, one trial found 100 mg/day DHEA
Fatigue during high-intensity exercise has been associated improved strength in older men.
with accumulation of lactic acid and reduction of muscle cell
pH. Alkalizing agents (sodium bicarbonate, sodium citrate, Recommendation: not recommended due to safety concerns.
phosphate salts) taken just prior to exercise, may improve
performance in events lasting either 1-10 minutes, or 30-60 Cautions: steroid effects may pose long-term health risks,
minutes.** including increased cancer and heart disease risks. May
cause acne and increased facial hair.
Recommendation: sodium bicarbonate (250-400 mg per kg
body weight or 115-180 mg per lb) or sodium citrate (300-500 Conjugated linoleic acid (CLA)
mg per kg body weight or 135-225 mg per lb), dissolved in at CLA is an altered form of the linoleic acid that is found in
least 500 ml (2 cups) of fluid. This amount can be taken all at small amounts in some foods. Animal research and some
once at least one hour prior to exercise or may be divided into human studies have suggested CLA might aid improve body
smaller doses and taken over several hours. composition and aid in weight loss. Consistent results appear
to require over 3 grams/day CLA. However, effects in humans
Caution: may cause gastrointestinal upset are minor, and are sometimes accompanied by adverse effects
on cardiovascular risk factors.
HMB (beta hydroxy-beta-methylbutyrate) is a metabolite of Recommendation: not recommended due to safety concerns.
leucine that appears to play a role in protein synthesis.
Research has found no benefit of HMB supplementation in
Health and Performance Concerns for Athletes Strength, Speed, Body Composition / Page 7
Cautions: may adversely affect blood lipids, insulin function,
inflammatory markers, and endothelial function
Health and Performance Concerns for Athletes / Page 8
Exercise recovery Dietary practices and supplements
with unproved benefits
Free radical activity results from strenuous exercise and may
High fat diet and fat loading
lead to muscle damage and reduced performance. Post-
exercise muscle soreness may be reduced and strength
Arginine/Ornithine (for body composition and strength)
recovery accelerated by taking vitamin C before and after
Beta-sitosterol/Beta-sitosterol glucoside (in combination for
reducing the risk of post-exercise infection)
Recommendation: 400-3000 mg/day for several days prior and
Branched-chain amino acids (for high altitude and extreme
following intense exercise.
temperature, for reducing the risk of post-exercise
infection, or for preventing decline of mental functioning
Other antioxidant approaches
Vitamin E may reduce biochemical indicators of free radical
activity and muscle damage in athletes, but no research has
investigated whether this leads to improved performance,
reduced post-exercise muscle soreness, etc.
Zinc (50 mg/day) and copper (3 mg/day) significantly reduced
Gamma-oryzanol & ferulic acidInosine
evidence of post-exercise free radical activity in one study.
Recommendation: include vitamin E, zinc and copper in daily
Medium chain triglycerides
Nitrous oxide supplements
Immune system protection Octacosanol
Ornithine alpha-ketoglutarate (OKG)
Glutamine Oxygen boosters
Strenuous exercise has been associated with immune Phosphorus
suppression and an increased risk of post-exercise infection. Pyruvate (for improving body composition with strength
Glutamine levels are also reduced by strenuous exercise, and training in untrained people only)
glutamine supplementation reduced reported post-exercise Ribose
infections in one controlled trial. Vitamin B-complex
Recommendations: Athletes engaged in intense, prolonged Cordyceps
exercise who are concerned with the risk of post-exercise Guaraná
infection can take 5 grams immediately after exercise, and Kola
again two hours later. Tribulus
Health and Performance Concerns for Athletes Exercise recovery / Page 9
Recent Sports Nutrition Abstracts
Nutrient Deficiency is especially true, as many of these factors can be prevented
with careful management.
Female athlete triad
J Orthop Sports Phys Ther. 2003 Oct;33(10):594-614.
Why are the three corners of the triad inter-related?
The female athlete triad: an emerging role for physical therapy.
The three corners of the triad are inter-related through
psychological and physiological mechanisms. The
Department of Physical Therapy, Marquette University,
psychological pressures to perform to an optimal standard,
Milwaukee, WI 53201-1881, USA. email@example.com
and thus often a perceived requirement to maintain a low
Over the last thirty years, participation by girls and women in
body mass, result in a high volume of training. The high
organized athletics has increased dramatically. This presents
volume of training and low energy intake, in addition to stress
unique challenges in the area of sports medicine,
hormones produced by psychological stress, may lead to a
orthopaedics, and pediatrics. While the benefits of
physiological alteration in the endocrinological control of the
participation in sports and exercise vastly outweigh the risks
menstrual cycle, which may ultimately lead to the athlete
of permanent injury, an evolving concern is the number of
becoming amenorrhoeic (loss of cycle after menarche). The
stress fractures in active women. The female athlete triad
consequence of being amenorrhoeic through dysfunction of
("triad") describes the coexistence of 3 distinct medical
the hypothalamus and pituitary is a decreased production of
conditions that may occur in athletic girls and women.
oestrogen. This hormone has a huge role in maintaining
Originally, the triad included eating disorders, amenorrhea,
adequate bone mineral density, and a hypo-oestrogenic state
and osteoporosis. Presently, it includes eating
(low oestrogen) thus is associated with low bone mineral
disorders/disordered eating behavior,
density and an increased risk of osteoporosis.
amenorrhea/oligomenorrhea, and decreased bone mineral
density (osteoporosis and osteopenia). Briefly, when coupled
with inadequate nutrition, the high caloric expenditure of
The normal regular, healthy menstrual cycle (eumenorrhoea) is
exercise training results in a sustained negative caloric
about 26-35 days, is controlled by the hypothalamus and
balance or low energy availability, which is exquisitely sensed
pituitary glands, and is divided simplistically into two phases
by the hypothalamus, initiating a complex neuroendocrine
by the occurrence mid-cycle of ovulation. The first half of the
adaptive cascade. This cascade is associated with changes in
cycle is the follicular phase and the second half the luteal
the hypothalamic-pituitary-ovarian axis, such that estrogen
phase. The follicular phase is characterised by gradually
levels are decreased, resulting in reproductive dysfunction
increasing levels of oestrogen produced primarily by the
that may include amenorrhea, oligomenorrhea, or anovulation.
ovaries, while the luteal phase is characterised by high
Low estrogen in otherwise young healthy women, like
concentrations of oestrogen and progesterone. Loss of
menopause, is associated with decreased bone mineral
oestrogen is associated with an increased risk of osteoporosis
density and increased risk of fractures. The triad is not an
and coronary artery disease.
inevitable consequence of participation in sports or physical
activity at any level, however, exercise may contribute to the
Menstrual cycle disturbances can progress from luteal phase
disruption of caloric balance. The triad is a complex disorder
defects to anovulation (no ovulation) and then to
that requires intervention by a multidisciplinary team.
oligomenorrhoea (irregular cycles) and amenorrhoea. The
diagnosis of luteal phase defects is completed with measures
BMJ 2005;330:244-246 (29 January),
such as a luteal phase less than 10 days long, inadequate
Clinical review: Female athlete triad
progesterone concentration, ultrasound measurement of pre-
ovulatory follicle diameter, and endometrial biopsy.
The "female athlete triad" has long been recognised as a
Causes in athletes
syndrome that has the potential to affect female athletes and
Causes of menstrual disorders are multiple and not completely
consists of three inter-related disorders:
understood. Pulsatile release of luteinising hormone is
decreased, which leads initially to luteal phase defects. In
addition, compared with sedentary women, women with luteal
phase defects and amenorrhoea have higher concentrations
of growth hormone and cortisol and lower concentrations of
The potential impact of each of, and the combination of, these
leptin, insulin, and triiodothyronine. These hormones are
disorders is detrimental to performance and to health.
related to metabolism, and thus to nutritional and metabolic
Certainly, the increased risk of infertility, stress fractures,
status. If energy availability is low over a period of time, as
eating disorders, and osteoporosis in later life is a high price
indicated by these hormones, the menstrual cycle is
to pay for involvement in an essentially healthy activity. This
temporarily "switched off" or suppressed to conserve energy.
Recent Sports Nutrition Abstracts Nutrient Deficiency / Page 10
Eating disorder or disordered eating? of sedentary controls than that of the spine. This suggests
Some female athletes do have a classic eating disorder, that regular running (or weight bearing activity) can offset
potentially driven by a need to maintain a low body mass for bone loss because of menstrual disturbances.
performance. Anorexia, however, has specific clinical Treatment of female athlete triad
diagnostic criteria, and not all athletes satisfy the criteria that Prevention is better than treatment, but prevention in athletes
indicate a disturbance in how they experience body weight or is made difficult by the nature of the game. Athletes will resist
shape. The term "anorexia athletica" has been used to increasing body weight, decreasing training loads, and using
distinguish between pathological anorexia and eating the contraceptive pill (because of worries about weight gain,
disorders associated with training and sports performance. breast tenderness, and mood changes). In addition, athletes
The criteria for this include perfectionism, compulsiveness, will find it difficult to admit to menstrual problems and
competitiveness, high self motivation, menstrual disordered eating or eating disorders. These points should be
disturbances, and at least one unhealthy method of weight kept firmly in mind when consulting with athletes.
control (fasting, vomiting, and use of diet pills, laxatives, or Perhaps the first step is for all individuals and agencies
diuretics). In reality, athletes in this category will show signs involved with female athletes to be made fully aware of the
of disordered eating, as opposed to an eating disorder, and potential causes, mechanisms, and long term risks of the
clinical observations indicate a prevalence of 15-60% for female athlete triad. In addition, women athletes, their parents,
disordered eating, with 50% of these women compulsively and medical staff should be informed about the triad and its
overexercising. This will obviously lead to a decreased energy pitfalls. The management of the athlete, however, is most
intake and thus a negative energy balance. imperative.
Osteoporosis or osteopenia? Eating disorders
Osteoporosis is defined as a bone mineral density more than The treatment of true eating disorders should be undertaken
2.5 standard deviations below the average for young adults only by qualified staff on an inpatient or outpatient basis. The
and is associated with a reduction in bone mass with no treatment plan will vary for each individual on the basis of
alteration in the mineralisation of bone tissue. Bone tissue psychology and environment, but several common sense
responds well to mechanical stress, and thus exercise, guidelines exist.
alongside nutrition, is essential in the teenage years to attain
peak bone mass. Women with low energy availability and low The ultimate goal is to increase the nutritional status of the
oestrogen concentrations, however, have increased risk of woman. This will reverse many of the symptoms associated
becoming osteoporotic. with disordered eating (for example, bloating, constipation,
fatigue, lanugo, and dry skin—although not loss of enamel
Oestrogen protects the skeleton from bone resorption, while from teeth), reverse menstrual disorders, and help reduce the
deficiencies in calcium, vitamin D, and other bone trophic risk of osteopenia or osteoporosis. Of course, many of these
substances from inadequate nutritional intake also lead to changes will ultimately increase muscle strength, decrease the
increased bone resorption. Long term risk of osteoporosis risk of injury, and thus increase training and sports
seems to be reduced by attaining a good peak bone mineral performance.
density in early life and by lifelong exposure to oestrogen.
Thus, long periods of amenorrhoea may increase the long Menstrual disturbances
term risk of osteoporosis. Once disturbances have been established as non-pathological
(the athlete should be medically assessed), the treatment is
Ostoeopenia is much more common than osteoporosis in based on training load and nutritional intake. Athletes will
female athletes and associated with decalcification. benefit from decreasing the intensity or duration of training
Researchers have called for osteopenia to replace by 10%; they then should increase energy intake by initially
osteoporosis in the triad. small amounts.
Effects of menstrual disturbances on bone mineral density Treatment is reliant on oestrogen replacement. Oestrogen
Studies have consistently shown lower bone mineral density replacement can be provided with the contraceptive pill,
in amenorrhoeic athletes than eumenorrhoeic athletes. The although progestogen-only pills and the mini pill should be
bone mineral density of amenorrhoeic runners has been avoided. If the athlete agrees to take the pill, she should
reported to be lower at the spine (-5%), hip (-6 %), and whole understand that it does not correct the underlying problem. If
body (-3%) than in eumenorrhoeic runners. Furthermore, menses (bleeding) is not desired, the practitioner can
eumenorrhoeic runners with disordered eating patterns have sometimes provide monophasic pills in which the placebo
lower bone mineral density at the spine (-11%), hip (-5%), and week is missing. This, however, should only be a short term
whole body (-5%) than eumenorrhoeic runners without approach. Hormone replacement therapy, as provided for
disordered eating. Athletes with less severe menstrual postmenopausal women, has been successful in only a few
disruption have intermediate bone densities. The bone mineral studies. Hormone replacement therapy with unopposed
density of the femur in amenorrhoeic athletes is closer to that
Nutrient Deficiency / Page 2
oestrogens should be avoided and should not be used for BACKGROUND: Tissue iron depletion may negatively affect
long periods. endurance performance and muscle fatigability. OBJECTIVE:
We investigated tissue-level iron depletion and progressive
Other treatments recommended for bone loss are specific fatigue of the quadriceps during dynamic knee-extension
oestrogen receptor modulators, intranasal calcitonin, and exercise in young women. DESIGN: Twenty iron-depleted
bisphosphonates. These products are used primarily in older (serum ferritin < 20 micro g/L), nonanemic (hemoglobin > 110
women, and little is known about their effects on bone mineral g/L) women (macro x +/- SEM age: 29.1 +/- 1.2 y) received iron
density in amenorrhoeic women. Calcium intake should be (iron group) or placebo (placebo group) for 6 wk in a
increased to 1500-2000 mg a day, and calcium should be taken randomized, double-blind trial (n = 10 per group). A protocol
alongside vitamin D. Calcium does not increase bone mineral integrating 2-3-s maximal voluntary static contractions
density but may aid in preventing further decreases. (MVCs) with dynamic knee extensions was used to assess
fatigue. RESULTS: No significant differences between the
Iron groups in baseline iron status, MVC at rest, or MVC at the
Am J Clin Nutr. 2004 Mar;79(3):437-43. end of the protocol were observed. After treatment, serum
Tissue iron deficiency without anemia impairs adaptation in iron and transferrin saturation increased significantly in the
endurance capacity after aerobic training in previously iron group (P = 0.02 and P = 0.03, respectively). Serum
untrained women. transferrin receptor concentrations increased significantly in
Brownlie T 4th, Utermohlen V, Hinton PS, Haas JD. the placebo group (P < 0.01) but not in the iron group. After
Division of Nutritional Sciences, Cornell University, Ithaca, treatment, the rate of decrease in MVC was attenuated in the
NY 14853, USA. firstname.lastname@example.org iron group but not in the placebo group (P = 0.01). In the iron
BACKGROUND: We previously showed that iron group, MVC at the sixth minute of the fatigue protocol and
supplementation significantly improves iron status and MVC at the end of the protocol were approximately 15% (P =
maximal work capacity in previously untrained, marginally 0.04) and approximately 27% higher (P < 0.01), respectively,
iron-deficient women with a baseline serum transferrin after treatment. These improvements were not related to
receptor concentration > 8.0 mg/L. However, the effect of changes in iron-status indexes or tissue iron stores, although
transferrin receptor status on adaptation in endurance power was low (< 0.50) to detect these relations.
capacity after aerobic training in these subjects has not been CONCLUSIONS: Iron supplementation was associated with a
fully explored. OBJECTIVE: Our objective was to examine the significant improvement in muscle fatigability. Interpretation
effect of baseline serum transferrin receptor status on regarding the direct role of tissue iron status is limited by the
adaptations in endurance capacity. DESIGN: Forty-one study's low power to detect relations between tissue iron
untrained, iron-depleted, nonanemic women were randomly improvement and decreased muscle fatigue.
assigned to receive either 100 mg FeSO(4) or a placebo for 6
wk in a double-blind trial. All subjects trained on cycle Zinc
ergometers 5 d/wk for the last 4 wk of the study. Endurance Am J Clin Nutr. 2005 May;81(5):1045-51.
capacity was assessed at baseline and after treatment by Low dietary zinc decreases erythrocyte carbonic anhydrase
using a 15-km time trial conducted on a cycle ergometer. activities and impairs cardiorespiratory function in men during
RESULTS: Significant treatment effects were observed for exercise.
time to complete the 15-km time trial, work rate, and Lukaski HC.
percentage of maximal oxygen uptake in subjects with a BACKGROUND: The role of zinc in promoting physiologic
baseline serum transferrin receptor concentration > 8.0 mg/L. function during exercise is not well understood. Although
No significant treatment effects were observed in subjects some zinc-containing enzymes are postulated to regulate
with a normal baseline transferrin receptor concentration. energy expenditure, data are limited on the effect of restricted
CONCLUSIONS: Our findings suggest that, in the presence of dietary zinc on metabolic responses during exercise.
overt tissue iron deficiency, iron deficiency without anemia OBJECTIVE: This study determined the effects of low zinc
impairs adaptation in endurance capacity after aerobic training intake on carbonic anhydrase activity in red blood cells
in previously untrained women. This impairment can be (RBCs) and cardiorespiratory function during exercise.
corrected with iron supplementation. DESIGN: In this double-blind, randomized crossover study, 14
men aged 20-31 y were fed low-zinc and supplemented (3.8
Am J Clin Nutr. 2003 Feb;77(2):441-8. and 18.7 mg/d) diets made up of Western foods for 9-wk
Iron supplementation improves progressive fatigue resistance periods with a 6-wk washout. Peak work capacity, determined
during dynamic knee extensor exercise in iron-depleted, by using a cycle ergometer and a graded, progressive
nonanemic women. protocol, and a prolonged submaximal test (70% peak
Brutsaert TD, Hernandez-Cordero S, Rivera J, Viola T, Hughes intensity for 45 min) were administered during the second and
G, Haas JD. ninth weeks of each diet period. RESULTS: Dietary zinc did
Department of Anthropology, the State University of New not affect hemoglobin or hematocrit. Low dietary zinc resulted
York at Albany, 12222, USA. email@example.com in lower (P < 0.05) serum and erythrocyte zinc concentrations,
zinc retention, and total carbonic anhydrase and isoform
Nutrient Deficiency / Page 3
activities in RBCs. Peak oxygen uptake, carbon dioxide exercise capacity and performance of humans. Physically
output, and respiratory exchange ratio were lower (P < 0.05), active people generally consume amounts of vitamins and
and ventilatory equivalents for metabolic responses during minerals consistent with the recommendations for the general
exercise were greater (P < 0.05), with low than with public. However, when intakes are less than
supplemental zinc intake. Similar functional responses were recommendations, some noticeable functional impairments
observed during prolonged, submaximal exercise. occur. Acute or short-term marginal deficiencies, identified by
CONCLUSION: These findings indicate that low dietary zinc blood biochemical measures of vitamin B status, had no
is associated with significant reductions in zinc status, impacts on performance measures. Severe deprivation of
including RBC carbonic anhydrase activities, and impaired folate and vitamin B12 result in anemia and reduce endurance
metabolic responses during exercise. work performance. Evidence of vitamin A and E deficiencies in
athletic individuals is lacking apparently because body
Clin Hemorheol Microcirc. 1999;20(1):1-10. storage is appreciable. In contrast to vitamins, marginal
Effects of zinc supplementation on blood rheology during mineral deficiencies impair performance. Iron deficiency, with
exercise. or without anemia, impairs muscle function and limits work
Khaled S, Brun JF, Cassanas G, Bardet L, Orsetti A. capacity. Magnesium deprivation increases oxygen
We previously reported a higher blood viscosity at corrected requirements to complete submaximal exercise and reduces
hematocrit (45%) (explained by a higher value of erythrocyte endurance performance. Use of vitamin and mineral
rigidity) in football players with low serum zinc (Zn) and thus supplements does not improve measures of performance in
presumably Zn deficiency; subjects with low serum zinc had people consuming adequate diets. Young girls and
also an impairment in performance. This interventional study individuals participating in activities with weight
was undertaken in order to assess the effects of zinc classifications or aesthetic components are prone to nutrient
supplementation (compared to placebo) on blood rheology deficiencies because they restrict food intake and specific
and performance either at rest or during exercise. Ten male micronutrient-rich foods. This information will be useful to
healthy volunteers (age: 26+/-1.3 yr; weight 67.9+/-2.24 kg; professionals who counsel physically active people and
height 177+/-3 cm) received at random order either zinc (20 scientific groups who make dietary recommendations to
mg/day) and placebo, according to a double blind cross -over improve health and optimize genetic potential.
procedure, during seven days. In each case on the eighth day Jeukendrup AE, Jentjens RL, Moseley L. Nutritional
they performed a 25 min submaximal exercise-test. At rest considerations in triathlon. Sports Med. 2005;35(2):163-81.
blood viscosity at corrected hematocrit 45% (gamma = 1000 Triathlon combines three disciplines (swimming, cycling and
s(-1)) was lower after Zn (3.56+/-0.14 vs. 4.13+/-0.16 mPa.s, p = running) and competitions last between 1 hour 50 minutes
0.009), explained by a lower RBC rigidity index 'k' according to (Olympic distance) and 14 hours (Ironman distance).
Quemada's equation (1.65+/-0.07 vs. 1.84+/-0.08, p = 0.03). Independent of the distance, dehydration and carbohydrate
Hematocrit and plasma viscosity were unchanged, but RBC (CHO) depletion are the most likely causes of fatigue in
aggregation was decreased (laser retrodiffusion-derived triathlon, whereas gastrointestinal (GI) problems,
aggregation time 'Ta' 3.52+/-0.51 vs. 2.75+/-0.59, p = 0.02). The hyperthermia and hyponatraemia are potentially health
increase in blood viscosity during exercise is lower after Zn threatening, especially in longer events. Although glycogen
than placebo. Blood viscosity at corrected hematocrit 45% supercompensation may be beneficial for triathlon
remains unchanged during exercise after Zn, yet it increases performance (even Olympic distance), this does not
after placebo. RBC rigidity index 'k' remains lower during necessarily have to be achieved by the traditional
exercise after Zn. The rating of perceived exertion (Borg's supercompensation protocol. More recently, studies have
scale) at the 20th minute of exercise is lower after zinc (5.6+/- revealed ways to increase muscle glycogen concentrations to
0.4 vs. 6.6+/-0.4, p = 0.008). This study confirms that Zn very high levels with minimal modifications in diet and
improves erythrocyte deformability, decreases the exercise- training. During competition, cycling provides the best
induced acute increase in blood viscosity, and improves opportunity to ingest fluids. The optimum CHO concentration
exercise tolerance. Since Zn deficiencies are not unfrequent in seems to be in the range of 5-8% and triathletes should aim to
sportsmen, these findings may be potentially relevant to achieve a CHO intake of 60-70 g/hour. Triathletes should
sports nutrition. attempt to limit body mass losses to 1% of body mass. In all
cases, a drink should contain sodium (30-50 mmol/L) for
Other deficiencies and special needs groups optimal absorption and prevention of hyponatraemia. Post-
Lukaski HC. Vitamin and mineral status: effects on physical exercise rehydration is best achieved by consuming
performance. Nutrition. 2004 Jul-Aug;20(7-8):632-44. beverages that have a high sodium content (>60 mmol/L) in a
Public health recommendations encourage the selection of a volume equivalent to 150% of body mass loss. GI problems
balanced diet and increasing physical activity to foster health occur frequently, especially in long-distance triathlon.
and well-being. Whereas the adverse effects of restricted Problems seem related to the intake of highly concentrated
intakes of protein, fat, and carbohydrate on physical carbohydrate solutions, or hyperosmotic drinks, and the
performance are well known, there is limited information about intake of fibre, fat and protein. Endotoxaemia has been
the impact of low intakes of vitamins and minerals on the suggested as an explanation for some of the GI problems, but
Nutrient Deficiency / Page 4
this has not been confirmed by recent research. Although and during the pre-contest phase the diet should be
mild endotoxaemia may occur after an Ironman-distance hypoenergetic (approximately 15% decrease in energy intake).
triathlon, this does not seem to be related to the incidence of
GI problems. Hyponatraemia has occasionally been reported, Barr SI, Rideout CA. Nutritional considerations for vegetarian
especially among slow competitors in triathlons and probably athletes. Nutrition. 2004 Jul-Aug;20(7-8):696-703.
arises due to loss of sodium in sweat coupled with very high With the growing interest in the potential health benefits of
intakes (8-10 L) of water or other low-sodium drinks. plant-based diets, it is relevant to consider whether vegetarian
dietary practices could influence athletic performance.
Lambert CP, Frank LL, Evans WJ. Macronutrient Accordingly, this review examines whether nutrients that may
considerations for the sport of bodybuilding. Sports Med. differ between vegetarian and omnivorous diets could affect
2004;34(5):317-27. physical performance. We also describe recent studies that
Nutrition, Metabolism, and Exercise Laboratory, Donald W. attempt to assess the effects of a vegetarian diet on
Reynolds Center on Aging, Department of Geriatrics, performance and comment on other nutritional aspects of
University of Arkansas for Medical Sciences, Little Rock, vegetarianism of relevance to athletes. Although well-
Arkansas 72205, USA. Participants in the sport of controlled long-term studies assessing the effects of
bodybuilding are judged by appearance rather than vegetarian diets on athletes have not been conducted, the
performance. In this respect, increased muscle size and following observations can be made: 1) well-planned,
definition are critical elements of success. The purpose of this appropriately supplemented vegetarian diets appear to
review is to evaluate the literature and provide effectively support athletic performance; 2) provided protein
recommendations regarding macronutrient intake during both intakes are adequate to meet needs for total nitrogen and the
'off-season' and 'pre-contest' phases. Body builders attempt to essential amino acids, plant and animal protein sources appear
increase muscle mass during the off-season (no competitive to provide equivalent support to athletic training and
events), which may be the great majority of the year. During performance; 3) vegetarians (particularly women) are at
the off-season, it is advantageous for the bodybuilder to be increased risk for non-anemic iron deficiency, which may limit
in positive energy balance so that extra energy is available endurance performance; and 4) as a group, vegetarians have
for muscle anabolism. Additionally, during the off-season, lower mean muscle creatine concentrations than do
adequate protein must be available to provide amino acids omnivores, and this may affect supramaximal exercise
for protein synthesis. For 6-12 weeks prior to competition, performance. Because their initial muscle creatine
body builders attempt to retain muscle mass and reduce body concentrations are lower, vegetarians are likely to experience
fat to very low levels. During the pre-contest phase, the greater performance increments after creatine loading in
bodybuilder should be in negative energy balance so that activities that rely on the adenosine
body fat can be oxidised. Furthermore, during the pre-contest triphosphate/phosphocreatine system. 5) Coaches and
phase, protein intake must be adequate to maintain muscle trainers should be aware that some athletes may adopt a
mass. There is evidence that a relatively high protein intake vegetarian diet as a strategy for weight control. Accordingly,
(approximately 30% of energy intake) will reduce lean mass the possibility of a disordered eating pattern should be
loss relative to a lower protein intake (approximately 15% of investigated if a vegetarian diet is accompanied by
energy intake) during energy restriction. The higher protein unwarranted weight loss.
intake will also provide a relatively large thermic effect that
may aid in reducing body fat. In both the off-season and pre- Campbell WW, Geik RA. Nutritional considerations for the
contest phases, adequate dietary carbohydrate should be older athlete. Nutrition. 2004 Jul-Aug;20(7-8):603-8.
ingested (55-60% of total energy intake) so that training In this review article, nutritional considerations of the aging
intensity can be maintained. Excess dietary saturated fat can athlete are discussed. The focuses of the review include
exacerbate coronary artery disease; however, low-fat diets energy, carbohydrate, protein, selected vitamins and minerals,
result in a reduction in circulating testosterone. Thus, we and fluids. Age-associated changes in body composition,
suggest dietary fats comprise 15-20% of the body builders' resting energy expenditure, and volume and intensity of
off-season and pre-contest diets. Consumption of training, may decrease the need for dietary energy and the
protein/amino acids and carbohydrate immediately before and intakes of macro- and micronutrients and fluids. The older
after training sessions may augment protein synthesis, muscle athlete should monitor nutrient intakes to insure adequacy,
glycogen resynthesis and reduce protein degradation. The especially regarding carbohydrate to promote glucose storage
optimal rate of carbohydrate ingested immediately after a and use as an energy source during exercise, and protein to
training session should be 1.2 g/kg/hour at 30-minute promote strength-training-induced muscle hypertrophy.
intervals for 4 hours and the carbohydrate should be of high Emphasis should also be placed on the dietary intakes of
glycemic index. In summary, the composition of diets for body certain micronutrients, as well as the potential need for
builders should be 55-60% carbohydrate, 25-30% protein supplementation of certain vitamins and minerals, including
and 15-20% of fat, for both the off-season and pre-contest the vitamins B(2), B(6), B(12), D, E, and folate, and the
phases. During the off-season the diet should be slightly minerals calcium and iron. Age-associated changes in
hyperenergetic (approximately 15% increase in energy intake) thermoregulation and an increased susceptibility to
Nutrient Deficiency / Page 5
dehydration underscore the critical importance to the older
athlete of adequate fluid intake to sustain health and Pediatr Nephrol. 2001 Apr;16(4):374-82.
performance. Nutrition is a tool that the older athlete should Measurement of urinary concentration: a critical appraisal of
use to enhance exercise performance and health. methodologies.
Chadha V, Garg U, Alon US.
The measurement of urine concentration provides information
Fluid balance and dehydration concerning the kidney's ability to appropriately respond to
Sports Med. 2001;31(10):701-15. variations in fluid homeostasis. It also assists in the
Fluid and electrolyte balance in ultra-endurance sport. interpretation of other tests performed on the same urine
Rehrer NJ. specimen. The gold standard of estimating urinary
School of Physical Education and Department of Human concentration is the measurement of its osmolality; however,
Nutrition, Otago University, Dunedin, New Zealand. this procedure is not readily available to the practicing
firstname.lastname@example.org physician. Therefore, urine concentration is usually
It is well known that fluid and electrolyte balance are critical to determined by measurement of its specific gravity (SG), which
optimal exercise performance and, moreover, health provides a fair estimate of urine osmolality. Over the years
maintenance. Most research conducted on extreme sporting numerous tests have been developed to measure urine SG in a
endeavour (>3 hours) is based on case studies and studies simple, quick, reliable and easily available method. These tests
involving small numbers of individuals. Ultra-endurance measure SG either directly (e.g., gravimetry) or by indirect
sportsmen and women typically do not meet their fluid needs methods (e.g., refractometry and reagent strip). All these tests
during exercise. However, successful athletes exercising over have certain limitations based on their underlying physical
several consecutive days come close to meeting fluid needs. principles. Specific gravity as measured by refractometry is
It is important to try to account for all factors influencing influenced by proteinuria, such that for each 10 g/l protein the
bodyweight changes, in addition to fluid loss, and all sources SG increases by 0.003. SG is also influenced by glucosuria
of water input. Increasing ambient temperature and humidity such that it increases by approximately 0.002 per 10 g/l
can increase the rate of sweating by up to approximately 1 glucose when compared with urinary osmolality. Unlike
L/h. Depending on individual variation, exercise type and osmolality, which is only affected by the number of particles,
particularly intensity, sweat rates can vary from extremely low refractometry is affected by number, mass and chemical
values to more than 3 L/h. Over-hydration, although not structure of the dissolved particles; hence large molecules like
frequently observed, can also present problems, as can radiographic contrast or mannitol will increase SG relative to
inappropriate fluid composition. Over-hydrating or meeting osmolality. The reagent strip is minimally affected by glucose,
fluid needs during very long-lasting exercise in the heat with mannitol or radiographic contrast. However, it is affected by
low or negligible sodium intake can result in reduced urinary pH such that only urine in the pH range of 7.0-7.5 can
performance and, not infrequently, hyponatraemia. Thus, with be correctly interpreted. The measurement of SG by reagent
large rates of fluid ingestion, even measured just to meet fluid strip is based on the ionic strength of the urine and thus is
needs, sodium intake is vital and an increased beverage significantly affected by the ionic composition of the urine
concentration [30 to 50 mmol/L (1.7 to 2.9 g NaCl/L) may be and by proteins which have an electric charge in solution. In
beneficial. If insufficient fluids are taken during exercise, our experience, SG measured by the refractometer is
sodium is necessary in the recovery period to reduce the consistently more accurate than the reagent strip. For the
urinary output and increase the rate of restoration of fluid clinician who is interpreting urine SG results, it is important to
balance. Carbohydrate inclusion in a beverage can affect the be aware of these limitations and understand the reasons for
net rate of water assimilation and is also important to possible potential errors of each particular method.
supplement endogenous reserves as a substrate for exercising
muscles during ultra-endurance activity. To enhance water J Athl Train. 2003 Dec;38(4):315-319.
absorption, glucose and/or glucose-containing carbohydrates Comparison of 3 Methods to Assess Urine Specific Gravity in
(e.g. sucrose, maltose) at concentrations of 3 to 5% Collegiate Wrestlers.
weight/volume are recommended. Carbohydrate Stuempfle KJ, Drury DG.
concentrations above this may be advantageous in terms of OBJECTIVE: To investigate the reliability and validity of
glucose oxidation and maintaining exercise intensity, but will refractometry, hydrometry, and reagent strips in assessing
be of no added advantage and, if hyperosmotic, will actually urine specific gravity in collegiate wrestlers. DESIGN AND
reduce the net rate of water absorption. The rate of fluid loss SETTING: We assessed the reliability of refractometry,
may exceed the capacity of the gastrointestinal tract to hydrometry, and reagent strips between 2 trials and among 4
assimilate fluids. Gastric emptying, in particular, may be below testers. The validity of hydrometry and reagent strips was
the rate of fluid loss, and therefore, individual tolerance may assessed by comparison with refractometry, the criterion
dictate the maximum rate of fluid intake. There is large measure for urine specific gravity. SUBJECTS: Twenty-one
individual variation in gastric emptying rate and tolerance to National Collegiate Athletic Association Division III
larger volumes. Training to drink during exercise is collegiate wrestlers provided fresh urine samples.
recommended and may enhance tolerance. MEASUREMENTS: Four testers measured the specific
Nutrient Deficiency / Page 6
gravity of each urine sample 6 times: twice by refractometry, Hyponatremia among runners in the Boston Marathon.
twice by hydrometry, and twice by reagent strips. RESULTS: Almond CS, Shin AY, Fortescue EB, Mannix RC, Wypij D,
Refractometer measurements were consistent between trials Binstadt BA, Duncan CN, Olson DP, Salerno AE, Newburger
(R =.998) and among testers; hydrometer measurements were JW, Greenes DS.
consistent between trials (R =.987) but not among testers; and BACKGROUND: Hyponatremia has emerged as an important
reagent-strip measurements were not consistent between cause of race-related death and life-threatening illness among
trials or among testers. Hydrometer (1.018 +/- 0.006) and marathon runners. We studied a cohort of marathon runners
reagent-strip (1.017 +/- 0.007) measurements were significantly to estimate the incidence of hyponatremia and to identify the
higher than refractometer (1.015 +/- 0.006) measurements. principal risk factors. METHODS: Participants in the 2002
Intraclass correlation coefficients were moderate between Boston Marathon were recruited one or two days before the
refractometry and hydrometry (R =.869) and low between race. Subjects completed a survey describing demographic
refractometry and reagent strips (R =.573). The hydrometer information and training history. After the race, runners
produced 28% false positives and 2% false negatives, and provided a blood sample and completed a questionnaire
reagent strips produced 15% false positives and 9% false detailing their fluid consumption and urine output during the
negatives. CONCLUSIONS: Only the refractometer should be race. Prerace and postrace weights were recorded.
used to determine urine specific gravity in collegiate wrestlers Multivariate regression analyses were performed to identify
during the weight-certification process. risk factors associated with hyponatremia. RESULTS: Of 766
runners enrolled, 488 runners (64 percent) provided a usable
J Sports Sci. 2004 Jan;22(1):39-55. blood sample at the finish line. Thirteen percent had
Fluid and fuel intake during exercise. hyponatremia (a serum sodium concentration of 135 mmol per
Coyle EF. liter or less); 0.6 percent had critical hyponatremia (120 mmol
Human Performance Laboratory, Department of Kinesiology per liter or less). On univariate analyses, hyponatremia was
and Health Education, The University of Texas at Austin, associated with substantial weight gain, consumption of more
Austin, TX 78712, USA. email@example.com than 3 liters of fluids during the race, consumption of fluids
The amounts of water, carbohydrate and salt that athletes are every mile, a racing time of >4:00 hours, female sex, and low
advised to ingest during exercise are based upon their body-mass index. On multivariate analysis, hyponatremia was
effectiveness in attenuating both fatigue as well as illness due associated with weight gain (odds ratio, 4.2; 95 percent
to hyperthermia, dehydration or hyperhydration. When confidence interval, 2.2 to 8.2), a racing time of >4:00 hours
possible, fluid should be ingested at rates that most closely (odds ratio for the comparison with a time of <3:30 hours, 7.4;
match sweating rate. When that is not possible or practical or 95 percent confidence interval, 2.9 to 23.1), and body-mass-
sufficiently ergogenic, some athletes might tolerate body index extremes. CONCLUSIONS: Hyponatremia occurs in a
water losses amounting to 2% of body weight without substantial fraction of nonelite marathon runners and can
significant risk to physical well-being or performance when be severe. Considerable weight gain while running, a long
the environment is cold (e.g. 5-10 degrees C) or temperate (e.g. racing time, and body-mass-index extremes were associated
21-22 degrees C). However, when exercising in a hot with hyponatremia, whereas female sex, composition of fluids
environment ( > 30 degrees C), dehydration by 2% of body ingested, and use of nonsteroidal antiinflammatory drugs
weight impairs absolute power production and predisposes were not.
individuals to heat injury. Fluid should not be ingested at
rates in excess of sweating rate and thus body water and Br J Sports Med. 2005 Apr;39(4):205-11
weight should not increase during exercise. Fatigue can be Sweat rate and fluid turnover in American football players
reduced by adding carbohydrate to the fluids consumed so compared with runners in a hot and humid environment.
that 30-60 g of rapidly absorbed carbohydrate are ingested Godek SF, Bartolozzi AR, Godek JJ.
throughout each hour of an athletic event. Furthermore, OBJECTIVES: To determine sweat rate (SwR) and fluid
sodium should be included in fluids consumed during exercise requirements for American footballers practicing in a hot,
lasting longer than 2 h or by individuals during any event that humid environment compared with cross country runners in
stimulates heavy sodium loss (more than 3-4 g of sodium). the same conditions. METHODS: Fifteen subjects, 10
Athletes do not benefit by ingesting glycerol, amino acids or footballers and five runners, participated. On the 4th and 8th
alleged precursors of neurotransmitter. Ingestion of other day of preseason two a day practices, SwR during exercise
substances during exercise, with the possible exception of was determined in both morning and afternoon practices/runs
caffeine, is discouraged. Athletes will benefit the most by from the change in body mass adjusted for fluids consumed
tailoring their individual needs for water, carbohydrate and and urine produced. Unpaired t tests were used to determine
salt to the specific challenges of their sport, especially differences between groups. RESULTS: Overall SwR
considering the environment's impact on sweating and heat measured in litres/h was higher in the footballers than the
stress. cross country runners (2.14 (0.53) v 1.77 (0.4); p<0.01). Total
sweat loss in both morning (4.83 (1.2) v 1.56 (0.39) litres) and
Hyponatremia afternoon (4.8 (1.2) v 1.97 (0.28) litres) practices/runs, and
N Engl J Med. 2005 Apr 14;352(15):1550-6. daily sweat losses (9.4 (2.2) v 3.53 (0.54) litres) were higher in
Nutrient Deficiency / Page 7
the footballers (p<0.0001). The footballers consumed larger chemistries of 26 runners competing in an 160 km foot race in
volumes of fluid during both morning and afternoon temperatures which peaked at 38 degrees C. Blood was drawn
practices/runs (23.9 (8.9) v 5.5 (3.1) ml/min and 23.5 (7.3) v 13.6 pre-, mid- and post-race. Dietary intake and incidence of
(5.6) ml/min; p<0.01). For complete hydration, the necessary gastrointestinal distress or changes in mental status were
daily fluid consumption calculated as 130% of daily sweat determined by interview with runners approximately every 13
loss in the footballers was 12.2 (2.9) litres compared with 4.6 km. Twenty-three runners completed at least 88 kms and, of
(0.7) litres in the runners (p<0.0001). Calculated 24 hour fluid these 23 runners, 13 finished 160 km in a mean time of 26.2 +/-
requirements in the footballers ranged from 8.8 to 19 litres. 3.6 hours. RESULTS: Finishers ingested nearly 30,000 J, 19.4
CONCLUSIONS: The American footballers had a high SwR +/- 8.1 L of fluid and 16.4 +/- 9.5 g of sodium (Na). Sodium and
with large total daily sweat losses. Consuming large volumes fluid intake per hour was estimated to be 0.6 g/hour and 0.7
of hypotonic fluid may promote sodium dilution. L/hour, respectively. Electrolyte intake during the first half of
Recommendations for fluid and electrolyte replacement must the race was similar between those that finished the race and
be carefully considered and monitored in footballers to those that did not. Finishers ingested fluid at a greater rate
promote safe hydration and avoid hyponatraemia. than non-finishers (p = 0.01) and tended to meet their caloric
needs more closely than did non-finishers (p = 0.09). Body
Curr Sports Med Rep. 2002 Aug;1(4):197-207. weight was unchanged over time (ANOVA, p = 0.52). Serum
Hyponatremia in distance runners: fluid and sodium balance Na concentration tended to fall from 143 to 140 mEq/L during
during exercise. the race (p = 0.06), and was inversely correlated with weight
Noakes T. loss (p = 0.009). Serum Na concentration was lower mid-race in
UCT/MRC Research Unit for Exercise Science and Sports runners experiencing changes in mental status than in runners
Medicine, Department of Human Biology, University of Cape without changes (p = 0.04). Fluid intake was inversely
Town, Sports Science Institute of South Africa, Boundary correlated with serum Na concentrations (p = 0.04). Most of
Road, Newlands, 7700, South Africa. the runners experienced nausea or vomiting; these symptoms
firstname.lastname@example.org were not related to serum sodium concentration.
Since its first description in 1985, two opposing theories have Hyponatremia (<135 mEq/L) was seen in one runner at 88 kms,
evolved to explain the etiology of symptomatic hyponatremia but resolved by 160 km. Urinary sodium excretion decreased
of exercise. The first holds that the condition occurs only in (p = 0.002) as serum aldosterone concentration increased pre-
athletes who lose both water and sodium during exercise, and to post-race (p < 0.001). From start to finish of the race plasma
fail to fully replace their sodium losses. The second theory volume increased by 12%. CONCLUSIONS: Food and fluid
holds that the symptomatic form of this condition occurs in was ingested at a greater rate than described previously.
athletes who generate a whole body fluid overload as a result Runners consumed adequate fluid to maintain body weight
of an excessive fluid intake during prolonged exercise. It is although dietary sodium fell far short of the recommended 1
argued that the promotion of the idea that athletes should g/hour. The rate of fluid intake was greater in finishers than
drink as much as possible during exercise has produced, in non-finishers, and finishers tended to more nearly meet
rather than prevented, the recent increase in the incidence of their energy needs. Maintenance of body mass despite large
this condition. A series of case reports and laboratory studies exercise energy expenditures in extreme heat is consistent
reported in the past 2 years have established that it is a whole with fluid overload during a running event lasting more than
body fluid overload, resulting from sustained high rates of 24 hours in hot and humid conditions.
fluid intake, that causes the symptomatic hyponatremia of
exercise. There is no evidence that, in the absence of fluid Clin J Sport Med. 2002 Sep;12(5):279-84.
overload, the usual sodium deficits generated during exercise Oral salt supplementation during ultradistance exercise.
can cause this condition. These findings confirm that the Speedy DB, Thompson JM, Rodgers I, Collins M, Sharwood
potentially fatal condition of symptomatic hyponatremia K, Noakes TD.
would be eliminated from sport immediately if all athletes were Department of General Practice and Primary Care, University
advised of the dangers of ingesting as much fluid as possible of Auckland, New Zealand. email@example.com
during any exercise that lasts more than 4 hours. OBJECTIVE: The objective of this study was to determine
whether sodium supplementation 1) influences changes in
J Am Coll Nutr. 2002 Dec;21(6):553-9. body weight, serum sodium [Na], and plasma volume (PV),
Food intake and electrolyte status of ultramarathoners and 2) prevents hyponatremia in Ironman triathletes.
competing in extreme heat. SETTING: The study was carried out at the South African
Glace BW, Murphy CA, McHugh MP. Ironman triathlon. PARTICIPANTS: Thirty-eight athletes
Nicholas Institute of Sports Medicine and Athletic Trauma, competing in the triathlon were given salt tablets to ingest
New York, New York 10021, USA. during the race. Data collected from these athletes [salt intake
OBJECTIVE: To relate changes in laboratory indices to dietary group (SI)] were compared with data from athletes not given
intake during extremely prolonged running and to determine if salt [no salt group (NS)]. INTERVENTIONS: Salt tablets were
dietary intake influences the ability of runners to finish an 160 given to the SI group to provide approximately 700 mg/h of
km trail race. METHODS: We monitored intake and serum sodium. MAIN OUTCOME MEASUREMENTS: Serum
Nutrient Deficiency / Page 8
sodium, hemoglobin, and hematocrit were measured at race after the run and performance. There was a significant
registration and after the race. Weights were measured before correlation between changes in [Na(+)](plasma) and changes
and after the race. Members of SI were retrospectively in body weight. CONCLUSIONS: Exercise induced
matched to subjects in NS for 1) weight change and 2) pre- hyponatraemia in women is likely to develop from fluid
race [Na]. RESULTS: The SI group developed a 3.3-kg weight overload during prolonged exercise. This can be minimised
loss (p < 0.0001) and significantly increased their [Na] by the use of replacement fluids of high sodium
(delta[Na] 1.52 mmol/L; p = 0.005). When matched for weight concentration. Sodium replacement of at least 680 mg/h is
change during the race, SI increased their [Na] compared with recommended for women in a state of fluid overload during
NS (mean 1.52 versus 0.04 mmol/L), but this did not reach endurance exercise of four hours. However, higher
statistical significance (p = 0.08). When matched for pre-race [Na(+)](plasma) after the run and smaller decreases in
[Na], SI had a significantly smaller percent body weight loss [Na(+)](plasma) during the trials were no indication of better
than NS (-4.3% versus -5.1%; p = 0.04). There was no performance over four hours.
significant difference in the increase of [Na] in both groups
(1.57 versus 0.84 mmol/L). PV increased equally in both Rehydration
groups. None of the subjects finished the race with [Na] < 135 Int J Sport Nutr Exerc Metab. 2002 Mar;12(1):14-23.
mmol/L. CONCLUSIONS: Sodium ingestion was associated Effect of high and low rates of fluid intake on post-exercise
with a decrease in the extent of weight loss during the race. rehydration.
There was no evidence that sodium ingestion significantly Kovacs EM, Schmahl RM, Senden JM, Brouns F.
influenced changes in [Na] or PV more than fluid Department of Human Biology at Maastricht University, The
replacement alone in the Ironman triathletes in this study. Netherlands.
Sodium supplementation was not necessary to prevent the The effect of a high (H) and a low (L) rate of post-exercise
development of hyponatremia in these athletes who lost fluid consumption on plasma volume and fluid balance
weight, indicating that they had only partially replaced their restoration was investigated. Eight well-trained cyclists were
fluid and other losses during the Ironman triathlon. dehydrated at 3% of body weight (BW) by cycling at 28
degrees C. During the recovery period, they ingested a
Br J Sports Med. 2003 Aug;37(4):300-3; discussion 303. carbohydrate-electrolyte solution in a volume equivalent to
Effects of different sodium concentrations in replacement 120% of BW loss. Randomly, they ingested 60%, 40%, and
fluids during prolonged exercise in women. 20% in the 1st, 2nd, and 3rd hours of the recovery period,
Twerenbold R, Knechtle B, Kakebeeke TH, Eser P, Muller G, respectively (H), or 24% x h(-1) during 5 hours (L). BW loss
von Arx P, Knecht H. was similar for both trials and resulted in a total drink intake of
Institute of Sports Medicine, Swiss Paraplegic Centre, Nottwil, 2.6 +/- 0.1 kg. Urine output in H exceeded significantly that of
Switzerland. L in the 2nd and 3rd hours. This was reversed in the 5th and
OBJECTIVE: To investigate the effect of different sodium 6th hours. Plasma volume and fluid balance increased more
concentrations in replacement fluids on haematological rapidly in H compared to L. After 6 hours this difference
variables and endurance performance during prolonged disappeared. It is concluded that H results in a faster rate of
exercise. METHODS: Thirteen female endurance athletes plasma volume and fluid balance restoration compared to L,
completed three four hour runs on a 400 m track. despite a temporary large urine output.
Environmental conditions differed between the three trials: 5.3
degrees C and snow (trial 1), 19.0 degrees C and sunny
weather (trial 2), 13.9 degrees C and precipitation (trial 3). Endurance Nutrition
They consumed 1 litre of fluid an hour during the trials with Diet Composition/Fuels
randomised intake of fluids: one trial (H) with high sodium J Sports Sci. 2004 Jan;22(1):15-30.
concentration (680 mg/l), one trial (L) with low sodium Carbohydrates and fat for training and recovery.
concentration (410 mg/l), and one trial with only water (W). Burke LM, Kiens B, Ivy JL.
Before and after the trials, subjects were weighed and blood An important goal of the athlete's everyday diet is to provide
samples were taken for analysis of [Na(+)](plasma), packed the muscle with substrates to fuel the training programme that
cell volume, and mean corpuscular volume. RESULTS: The will achieve optimal adaptation for performance
mean (SD) decrease in [Na(+)](plasma) over the whole trial enhancements. In reviewing the scientific literature on post-
was significantly (p<0.001) less in trial H (2.5 (2.5) mmol/l) than exercise glycogen storage since 1991, the following guidelines
in trial W (6.2 (2.1) mmol/l). Mild hyponatraemia for the training diet are proposed. Athletes should aim to
([Na(+)](plasma) = 130-135 mmol/l) was observed in only six achieve carbohydrate intakes to meet the fuel requirements of
women (46%) in trial H compared with nine (69%) in trial L, their training programme and to optimize restoration of muscle
and 12 (92%) in trial W. Two subjects (17%) in trial W glycogen stores between workouts. General recommendations
developed severe hyponatraemia ([Na(+)](plasma)<130 can be provided, preferably in terms of grams of carbohydrate
mmol/l). No significant differences were found in performance per kilogram of the athlete's body mass, but should be fine-
or haematological variables with the three different fluids. tuned with individual consideration of total energy needs,
There was no significant correlation between[Na(+)](plasma) specific training needs and feedback from training
/ Page 9
performance. It is valuable to choose nutrient-rich endurance events lasting 90 min or more. Ingestion of
carbohydrate foods and to add other foods to recovery meals carbohydrate 3-4 h before exercise increases liver and muscle
and snacks to provide a good source of protein and other glycogen and enhances subsequent endurance exercise
nutrients. These nutrients may assist in other recovery performance. The effects of carbohydrate ingestion on blood
processes and, in the case of protein, may promote additional glucose and free fatty acid concentrations and carbohydrate
glycogen recovery when carbohydrate intake is suboptimal or oxidation during exercise persist for at least 6 h. Although an
when frequent snacking is not possible. When the period increase in plasma insulin following carbohydrate ingestion in
between exercise sessions is < 8 h, the athlete should begin the hour before exercise inhibits lipolysis and liver glucose
carbohydrate intake as soon as practical after the first output, and can lead to transient hypoglycaemia during
workout to maximize the effective recovery time between subsequent exercise in susceptible individuals, there is no
sessions. There may be some advantages in meeting convincing evidence that this is always associated with
carbohydrate intake targets as a series of snacks during the impaired exercise performance. However, individual experience
early recovery phase, but during longer recovery periods (24 should inform individual practice. Interventions to increase fat
h) the athlete should organize the pattern and timing of availability before exercise have been shown to reduce
carbohydrate-rich meals and snacks according to what is carbohydrate utilization during exercise, but do not appear to
practical and comfortable for their individual situation. have ergogenic benefits.
Carbohydrate-rich foods with a moderate to high glycaemic
index provide a readily available source of carbohydrate for Tarnopolsky M. Protein requirements for endurance athletes.
muscle glycogen synthesis, and should be the major Nutrition. 2004 Jul-Aug;20(7-8):662-8. Acute endurance
carbohydrate choices in recovery meals. Although there is exercise results in the oxidation of several amino acids. The
new interest in the recovery of intramuscular triglyceride total amount of amino acid oxidation during endurance
stores between training sessions, there is no evidence that exercise amounts to only 1-6% of the total energy cost of
diets which are high in fat and restricted in carbohydrate exercise. The branched chain amino acid, leucine, has been
enhance training. most often studied in relation to endurance exercise. Leucine
is oxidized by the enzyme, branched-chain oxo-acid
Sports Med. 1997 Aug;24(2):73-81. dehydrogenase (BCOAD). BCOAD is relatively inactive at
Carbohydrate-loading and exercise performance. An update. rest (approximately 4-7%) and is activated at the onset of
Hawley JA, Schabort EJ, Noakes TD, Dennis SC. exercise by dephosphorylation (to about 25%). After a period
This review suggests that there is little or no effect of of endurance exercise training, the activation of BCOAD and
elevating pre-exercise muscle glycogen contents above amino acid oxidation are attenuated, however the total amount
normal resting values on a single exhaustive bout of high- of BCOAD enzyme is up-regulated. A low energy and/or
intensity exercise lasting less than 5 minutes. Nor is there any carbohydrate intake will increase amino acid oxidation and
benefit of increasing starting muscle glycogen content on total protein requirements. With adequate energy and
moderate-intensity running or cycling lasting 60 to 90 carbohydrate intake, low to moderate intensity endurance
minutes. In such exercise substantial quantities of glycogen activity has little impact on dietary protein requirements and
remain in the working muscles at the end of exercise. 1.0 gPRO/kg/d is sufficient. The only situation where dietary
However, elevated starting muscle glycogen content will protein requirements exceed those for relatively sedentary
postpone fatigue by approximately equal to 20% in endurance individuals is in top sport athletes where the maximal
events lasting more than 90 minutes. During this type of requirement is approximately 1.6gPRO/kg/d. Although most
exercise, exhaustion usually coincides with critically low (25 endurance athletes get enough protein to support any
mmol/kg wet weight) muscle glycogen contents, suggesting increased requirements, those with low energy or
the supply of energy from glycogen utilisation cannot be carbohydrate intakes may require nutritional advice to
replaced by an increased oxidation of blood glucose. optimize dietary protein intake.
Glycogen supercompensation may also improve endurance
performance in which a set distance is covered as quickly as Jeukendrup AE, Aldred S. Fat supplementation, health, and
possible. In such exercise, high carbohydrate diets have been endurance performance. Nutrition. 2004 Jul-Aug;20(7-8):678-
reported to improve performance by 2 to 3%. 88.
Pre-exercise fat ingestion (i.e., long chain triacylglycerol
J Sports Sci. 2004 Jan;22(1):31-8. ingestion 1 to 4 h before exercise), medium-chain
Pre-exercise carbohydrate and fat ingestion: effects on triacylglycerols, fish oil, and conjugated linoleic acid have
metabolism and performance. been suggested to alter metabolism to achieve weight loss,
Hargreaves M, Hawley JA, Jeukendrup A. alter lipid profiles, or improve performance. However, studies
A key goal of pre-exercise nutritional strategies is to maximize have demonstrated that ingestion of meals with long-chain
carbohydrate stores, thereby minimizing the ergolytic effects triacylglycerols before exercise has little or no effect on
of carbohydrate depletion. Increased dietary carbohydrate metabolism and does not alter subsequent exercise
intake in the days before competition increases muscle performance. Also, medium-chain triacylglycerol
glycogen levels and enhances exercise performance in supplementation before or during exercise has not been
Endurance Nutrition / Page 10
shown to be ergogenic, although this could be related to the 10RM), with 60 seconds of rest between sets. Forty-five
small amounts of medium-chain triacylglycerol that can be minutes after exercise, subjects consumed meals of high fat
ingested before gastrointestinal discomfort occurs. Fish oil (HF, 37% carbohydrate, 18% protein, and 45% fat), high
may improve red blood cell deformability, but these effects are carbohydrate (HC, 79% carbohydrate, 20% protein, and 1%
likely to be small and do not seem to influence maximum fat), or water (CON). Fat and carbohydrate oxidation were
oxygen delivery or exercise performance. Conjugated linoleic determined at 15-minute periods after meal consumption for
acid has been implicated in weight loss, but based on the 165 minutes. Blood was collected at preexercise (pre), premeal
results of human studies it must be concluded that the effects (0 minutes), and 15, 30, 45, 60, 90, 120, 150, and 180 minutes
of conjugated linoleic acid on body weight loss are far less postmeal and was analyzed for insulin, glucose,
clear than those observed in animal studies. Most studies triacylglycerols, and glycerol. There were no significant
have not found any evidence for a beneficial effect of differences among the meal conditions for fat and
conjugated linoleic acid. carbohydrate oxidation. Insulin and glucose concentrations
were significantly higher (p < 0.05) following HC at 15, 30, 45,
60, and 90 minutes compared to HF and CON. Triacylglycerol
Strength, Speed, Body Composition concentrations were significantly higher (p < 0.05) following
Carbohydrate and fat HF at 90, 120, 150, and 180 minutes compared to HC and CON.
J Strength Cond Res. 2003 Feb;17(1):187-96. Fat and carbohydrate oxidation were not affected by
Carbohydrate supplementation and resistance training. differences in macronutrient meal consumption after an
Haff GG, Lehmkuhl MJ, McCoy LB, Stone MH. acute bout of resistance training. Different macronutrient
There is a growing body of evidence suggesting that the consumption does influence insulin, glucose, and
performance of resistance-training exercises can elicit a triacylglycerol concentrations after resistance exercise.
significant glycogenolytic effect that potentially could result
in performance decrements. These decrements may result in Body Composition
less than optimal physiological adaptations to training. Am J Clin Nutr. 1996 Sep;64(3 Suppl):436S-448S.
Currently some scientific evidence suggests that Why bioelectrical impedance analysis should be used for
carbohydrate supplementation prior to and during high - estimating adiposity.
volume resistance training results in the maintenance of Houtkooper LB, Lohman TG, Going SB, Howell WH.
muscle glycogen concentration, which potentially could result Department of Nutritional Sciences, University of Arizona,
in the maintenance or increase of performance during a Tucson 85721-0033, USA. firstname.lastname@example.org
training bout. Some researchers suggest that ingesting The whole-body bioelectrical impedance analysis (BIA)
carbohydrate supplements prior to and during resistance approach for estimating adiposity and body fat is based on
training may improve resistance-training performance. empirical relations established by many investigators.
Additionally, the ingestion of carbohydrates following Properly used, this noninvasive body-composition
resistance exercise enhances the resynthesis of muscle assessment approach can quickly, easily, and relatively
glycogen, which may result in a faster time of recovery from inexpensively provide accurate and reliable estimates of fat-
resistance training, thus possibly allowing for a greater free mass (FFM) and total body water (TBW) in healthy
training volume. On the basis of the current scientific populations. The estimated FFM or TBW values are used to
literature, it may be advisable for athletes who are performing calculate absolute and relative body fat amounts. When
high-volume resistance training to ingest carbohydrate different investigators follow the same standard BIA
supplements before, during, and immediately after resistance procedures and use the same population and criterion
training. method, similar prediction equations and relatively small
prediction errors have been reported for measurement of FFM
J Strength Cond Res. 2004 May;18(2):212-9. and TBW (SEE: 1.7-3.0 for FFM and 0.23-1.5 kg for TBW). The
Effects of different macronutrient consumption following a BIA approach is most appropriate for estimating adiposity of
resistance-training session on fat and carbohydrate groups in epidemiologic and field studies but has limited
metabolism. accuracy for estimating body composition in individuals.
Bosher KJ, Potteiger JA, Gennings C, Luebbers PE, Shannon When used as a simple index (stature2/ resistance), BIA is
KA, Shannon RM. more sensitive and specific for grading average adiposity in
Division of Health, Physical Education, and Recreation, groups than some other anthropometric indexes such as the
Virginia Commonwealth University, Richmond, Virginia 23284, body mass index. Prediction equations based on BIA have
USA. been validated and cross -validated in children, youths, adults,
The effect of consuming meals of different macronutrient and the elderly, in primarily white populations and, to a limited
content on substrate oxidation following resis tance exercise extent, in Asian, black, and Native American populations.
was examined in 9 resistance-trained men (26.2 +/- 2.4 years).
Subjects completed 3 resistance exercise bouts of 8 exercises Med Sci Sports Exerc. 2004 Mar;36(3):490-7.
and 1 warm-up set (50% of 10 repetition maximum [RM]), Body composition changes in bodybuilders: a method
which were followed by 3 sets of 10 repetitions (72.7 +/- 1.9% comparison.
/ Page 11
van Marken Lichtenbelt WD, Hartgens F, Vollaard NB, Ebbing
S, Kuipers H. Andersen LL, Tufekovic G, Zebis MK, et al. The effect of
Department of Human Biology, Maastricht University, The resistance training combined with timed ingestion of protein
Netherlands. Marken.Lichtenbelt@HB.unimaas.nl on muscle fiber size and muscle strength. Metabolism. 2005
INTRODUCTION: Few studies report on validation of body Feb;54(2):151-6.
composition changes using the four-compartment model (4C), Sports Medicine Research, Unit/Team Denmark Test Center,
and no such studies are available in strength training. Here we Bispebjerg Hospital, DK-2400 Copenhagen, Denmark.
present such a validation study for the determination of body LL_andersen@hotmail.com
fat and fat-free mass changes in bodybuilders, who used Acute muscle protein metabolism is modulated not only by
exercise and androgenic-anabolic steroids. METHODS: The resistance exercise but also by amino acids. However, less is
study was carried out with 27 male bodybuilders in a cross - known about the long-term hypertrophic effect of protein
sectional study. Fifteen of these subjects also participated in supplementation in combination with resistance training. The
an intervention program where body composition changes present study was designed to compare the effect of 14 weeks
were measured. The 4C model served as the gold standard. of resistance training combined with timed ingestion of
The alternative mechanistic methods were underwater isoenergetic protein vs carbohydrate supplementation on
weighing (uww), deuterium dilution (dil), three-compartment muscle fiber hypertrophy and mechanical muscle performance.
model incorporating total body water (3Cw), three- Supplementation was administered before and immediately
compartment model incorporating bone mineral content (3Cb), after each training bout and, in addition, in the morning on
and descriptive methods, namely dual-energy x-ray nontraining days. Muscle biopsy specimens were obtained
absorptiometry (DXA), prediction equations based on body from the vastus lateralis muscle and analyzed for muscle fiber
mass index (BMI), skinfold measurement, and bioimpedance cross-sectional area. Squat jump and countermovement jump
analyses. RESULTS: From the cross -sectional study, it were performed on a force platform to determine vertical jump
appeared that biases and errors of most mechanistic methods height. Peak torque during slow (30 degrees s -1) and fast (240
were small (maximal 0.5% BF and 3.4%BF, respectively; degrees s-1) concentric and eccentric contractions of the knee
exception 3Cb model). The 3Cw model had the lowest error extensor muscle was measured in an isokinetic dynamometer.
(0.9%BF). The descriptive methods had small biases After 14 weeks of resistance training, the protein group
(exception BMI) but relatively large errors (range: 5.5-8%). showed hypertrophy of type I (18% +/- 5%; P < .01) and type
Results on body composition changes (intervention study) II (26% +/- 5%; P < .01) muscle fibers, whereas no change
were comparable with the results from the cross -sectional above baseline occurred in the carbohydrate group. Squat
study. CONCLUSIONS: Using the 4C model as the standard jump height increased only in the protein group, whereas
for determination of body fat and fat-free mass, this study countermovement jump height and peak torque during slow
revealed that apart from the prediction equation based on isokinetic muscle contraction increased similarly in both
BMI and the 3Cb model, all methods gave acceptable group groups. In conclusion, a minor advantage of protein
mean values. When accurate measurements on body supplementation over carbohydrate supplementation during
composition and/or body composition changes on an resistance training on mechanical muscle function was found.
individual level are needed, only the 3Cw model could serve However, the present results may have relevance for
as an alternative for the 4C method. individuals who are particularly interested in gaining muscle
Protein, amino acids and derivatives
Curr Sports Med Rep. 2003 Aug;2(4):189-93. Am J Physiol Endocrinol Metab. 2004 Mar;286(3):E321-8.
Strength nutrition. Epub 2003 Oct 28.
Volek JS. Amino acid ingestion improves muscle protein synthesis in
Muscle strength is determined by muscle size and factors the young and elderly.
related to neural recruitment. Resistance training is a potent Paddon-Jones D, Sheffield-Moore M, Zhang XJ, Volpi E, Wolf
stimulus for increasing muscle size and strength. These SE, Aarsland A, Ferrando AA, Wolfe RR.
increases are, to a large extent, influenced and mediated by Department of Surgery, The University of Texas Medical
changes in hormones that regulate important events during Branch, Galveston, Texas 77550, USA. email@example.com
the recovery process following exercise. Provision of We recently demonstrated that muscle protein synthesis was
nutrients in the appropriate amounts and at the appropriate stimulated to a similar extent in young and elderly subjects
times is necessary to optimize the recovery process. This during a 3-h amino acid infusion. We sought to determine if a
review discusses the results of research that has examined the more practical bolus oral ingestion would also produce a
potential for nutrition and dietary supplements to impact the similar response in young (34 +/- 4 yr) and elderly (67 +/- 2 yr)
acute response to resistance exercise and chronic adaptations individuals. Arteriovenous blood samples and muscle
to resistance training. To date, the most promising strategies biopsies were obtained during a primed (2.0 micromol/kg)
to augment gains in muscle size and strength appear to be constant infusion (0.05 micromol.kg(-1).min(-1)) of L-[ring-
consumption of protein-carbohydrate calories before and after 2H5]phenylalanine. Muscle protein kinetics and mixed muscle
resistance exercise, and creatine supplementation. fractional synthetic rate (FSR) were calculated before and after
Strength, Speed, Body Composition / Page 12
the bolus ingestion of 15 g of essential amino acids (EAA) in sessions results in changes in blood amino acid
young (n = 6) and elderly (n = 7) subjects. After EAA concentration. However, the supplementation does not affect
ingestion, the rate of increase in femoral artery phenylalanine an acute physical performance.
concentration was slower in elderly subjects but remained
elevated for a longer period. EAA ingestion increased FSR in Whey and other whole protein supplements
both age groups by approximately 0.04%/h (P < 0.05). J Strength Cond Res. 2006 Aug;20(3):643-53.
However, muscle intracellular (IC) phenylalanine The effects of protein and amino acid supplementation on
concentration remained significantly higher in elderly subjects performance and training adaptations during ten weeks of
at the completion of the study (young: 115.6 +/- 5.4 nmol/ml; resistance training.
elderly: 150.2 +/- 19.4 nmol/ml). Correction for the free Kerksick CM, Rasmussen CJ, Lancaster SL, Magu B, Smith P,
phenylalanine retained in the muscle IC pool resulted in Melton C, Greenwood M, Almada AL, Earnest CP, Kreider RB.
similar net phenylalanine uptake values in the young and The purpose of this study was to examine the effects of whey
elderly. EAA ingestion increased plasma insulin levels in protein supplementation on body composition, muscular
young (6.1 +/- 1.2 to 21.3 +/- 3.1 microIU/ml) but not in elderly strength, muscular endurance, and anaerobic capacity during
subjects (3.0 +/- 0.6 to 4.3 +/- 0.4 microIU/ml). Despite 10 weeks of resistance training. Thirty-six resistance-trained
differences in the time course of plasma phenylalanine males (31.0 +/- 8.0 years, 179.1 +/- 8.0 cm, 84.0 +/- 12.9 kg, 17.8
kinetics and a greater residual IC phenylalanine concentration, +/- 6.6%) followed a 4 days-per-week split body part
amino acid supplementation acutely stimulated muscle protein resistance training program for 10 weeks. Three groups of
synthesis in both young and elderly individuals. supplements were randomly assigned, prior to the beginning
of the exercise program, in a double-blind manner to all
Amino Acids. 2003 Jul;25(1):85-94. subjects: 48 g per day (g.d(-1)) carbohydrate placebo (P), 40
Leucine supplementation does not enhance acute strength or g.d(-1) of whey protein + 8 g.d(-1) of casein (WC), or 40 g.d(-
running performance but affects serum amino acid 1) of whey protein + 3 g.d(-1) branched-chain amino acids + 5
concentration. g.d(-1) L-glutamine (WBG). At 0, 5, and 10 weeks, subjects
Pitkanen HT, Oja SS, Rusko H, Nummela A, Komi PV, were tested for fasting blood samples, body mass, body
Saransaari P, Takala T, Mero AA. composition using dual-energy x-ray absorptiometry (DEXA),
Neuromuscular Research Centre, Department of Biology of 1 repetition maximum (1RM) bench and leg press, 80% 1RM
Physical Activity, University of Jyvaskyla, Jyvaskyla, maximal repetitions to fatigue for bench press and leg press,
Finland. and 30-second Wingate anaerobic capacity tests. No changes
This study described the effect of leucine supplementation on (p > 0.05) were noted in all groups for energy intake, training
serum amino acid concentration during two different exercise volume, blood parameters, and anaerobic capacity. WC
sessions in competitive male power athletes. The subjects experienced the greatest increases in DEXA lean mass (P = 0.0
performed a strength exercise session (SES; n = 16; 26 +/- 4 +/- 0.9; WC = 1.9 +/- 0.6; WBG = -0.1 +/- 0.3 kg, p < 0.05) and
years) or a maximal anaerobic running exercise session DEXA fat-free mass (P = 0.1 +/- 1.0; WC = 1.8 +/- 0.6; WBG = -
(MARE; n = 12; 27 +/- 5 years) until exhaustion twice at a 7- 0.1 +/- 0.2 kg, p < 0.05). Significant increases in 1RM bench
day interval. The randomized subjects consumed drinks press and leg press were observed in all groups after 10
containing leucine (100 mg x kg/body weight before and weeks. In this study, the combination of whey and casein
during SES or 200 mg x kg/body weight before MARE) or protein promoted the greatest increases in fat-free mass after
placebo. Blood specimens taken 10 min before (B) and after 10 weeks of heavy resistance training. Athletes, coaches, and
(A) the sessions were analyzed for serum amino acids. In SES nutritionists can use these findings to increase fat-free mass
the concentration of leucine was distinctly higher in the and to improve body composition during resistance training.
leucine supplemented group than in the placebo group in
both B (p < 0.001) and A (p < 0.001) samples. The leucine Int J Sport Nutr Exerc Metab. 2006 Feb;16(1):65-77.
concentration decreased in placebo but not in the leucine A whey-supplemented, high-protein diet versus a high-
supplemented group following the exercise session. carbohydrate diet: effects on endurance cycling performance.
Isoleucine (p = 0.017) and valine (p = 0.006) concentration Macdermid PW, Stannard SR.
decreased more in the leucine supplemented group than in This study compared a training diet recommended for
placebo in A samples. In MARE the concentration of leucine endurance athletes (H-CHO) with an isoenergetic high protein
was higher in the leucine supplemented group than in placebo (whey supplemented), moderate carbohydrate (H-Pro) diet on
in both B (p < 0.001) and A (p < 0.001) samples and increased endurance cycling performance. Over two separate 7-d
(p < 0.001) in the supplemented group following the session. periods subjects (n = 7) ingested either H-CHO (7.9 +/- 1.9 g x
Isoleucine (p = 0.020) and valine (p = 0.006) concentration kg(-1) x d(-1) carbohydrate; 1.2 +/- 0.3 g x kg(-1) x d(-1) fat; 1.3
decreased in the supplemented group in A samples. There +/- 0.4 g x kg(-1) x d(-1) protein) or H-Pro (4.9 +/- 1.8 g x kg(-1)
were no differences in a counter movement jump after SES or x d(-1); 1.3 +/- 0.3 g x kg(-1) x d(-1); 3.3 +/- 0.4 g x kg(-1) x d(-1))
in the running performance in MARE between the leucine diet in a randomized, balanced order. On day 8 subjects cycled
supplemented group and placebo. These findings indicate (self-paced) for a body weight dependent (60 kJ/bm) amount
that consuming leucine before or before and during exercise of work. No differences occurred between energy intake (P =
Strength, Speed, Body Composition / Page 13
0.422) or fat intake (P = 0.390) during the two dietary CHO, 17.5 g whey protein, and 4.9 g AA 1 hr after resistance
conditions. Performance was significantly (P = 0.010) impaired exercise. In the other (CON), 100 g CHO was ingested instead.
following H-Pro (153 +/- 36) compared with H-CHO (127 +/- 34 They received a primed constant infusion of L-[2H5]-
min). No differences between treatments were observed for phenylalanine, and samples from femoral artery and vein, and
physiological measures taken during the performance trials. biopsies from vastus lateralis were obtained. The area under
These results indicate an ergolytic effect of a 7-d high protein the curve for net uptake of phenylalanine into muscle above
diet on self-paced endurance cycling performance. pre-drink value was 128+/- 42 mg x leg(- 1) (PAAC) versus
32+/- 10 mg x leg (-1) (CON) for the 3 hr after the drink (p =.04).
Med Sci Sports Exerc. 2004 Dec;36(12):2073-81. The net protein balance response to the mixture consisted of
Ingestion of casein and whey proteins result in muscle two components, one rapid immediate response, and a smaller
anabolism after resistance exercise. delayed response about 90 min after drink, whereas in CON
Tipton KD, Elliott TA, Cree MG, Wolf SE, Sanford AP, Wolfe only a small delayed response was seen. We conclude that
RR. after resistance exercise, a mixture of whey protein, AA, and
PURPOSE: Determination of the anabolic response to exercise CHO stimulated muscle protein synthesis to a greater extent
and nutrition is important for individuals who may benefit than isoenergetic CHO alone. Further, compared to previously
from increased muscle mass. Intake of free amino acids after reported findings, the addition of protein to an AA+ CHO
resistance exercise stimulates net muscle protein synthesis. mixture seems to extend the anabolic effect.
The response of muscle protein balance to intact protein
ingestion after exercise has not been studied. This study was Brown EC, DiSilvestro RA, Babaknia A, Devor ST. Soy versus
designed to examine the acute response of muscle protein whey protein bars: effects on exercise training impact on lean
balance to ingestion of two different intact proteins after body mass and antioxidant status. Nutr J 2004;3:22.
resistance exercise. METHODS: Healthy volunteers were Department of Sport & Exercise Sciences, The Ohio State
randomly assigned to one of three groups. Each group University, Columbus, Ohio, USA. firstname.lastname@example.org
consumed one of three drinks: placebo (PL; N = 7), 20 g of BACKGROUND: Although soy protein may have many health
casein (CS; N = 7), or whey proteins (WH; N = 9). Volunteers benefits derived from its associated antioxidants, many male
consumed the drink 1 h after the conclusion of a leg extension exercisers avoid soy protein. This is due partly to a popular,
exercise bout. Leucine and phenylalanine concentrations were but untested notion that in males, soy is inferior to whey in
measured in femoral arteriovenous samples to determine promoting muscle weight gain. This study provided a direct
balance across the leg. RESULTS: Arterial amino acid comparison between a soy product and a whey product.
concentrations were elevated by protein ingestion, but the METHODS: Lean body mass gain was examined in males from
pattern of appearance was different for CS and WH. Net a university weight training class given daily servings of
amino acid balance switched from negative to positive after micronutrient-fortified protein bars containing soy or whey
ingestion of both proteins. Peak leucine net balance over time protein (33 g protein/day, 9 weeks, n = 9 for each protein
was greater for WH (347 +/- 50 nmol.min(-1).100 mL(-1) leg) treatment group). Training used workouts with fairly low
than CS (133 +/- 45 nmol.min(-1).100 mL(-1) leg), but peak repetition numbers per set. A control group from the class (N
phenylalanine balance was similar for CS and WH. Ingestion = 9) did the training, but did not consume either type protein
of both CS and WH stimulated a significantly larger net bar. RESULTS: Both the soy and whey treatment groups
phenylalanine uptake after resistance exercise, compared with showed a gain in lean body mass, but the training-only group
the PL (PL -5 +/- 15 mg, CS 84 +/- 10 mg, WH 62 +/- 18 mg). did not. The whey and training only groups, but not the soy
Amino acid uptake relative to amount ingested was similar for group, showed a potentially deleterious post-training effect
both CS and WH (approximately 10-15%). CONCLUSIONS: on two antioxidant-related related parameters.
Acute ingestion of both WH and CS after exercise resulted in CONCLUSIONS: Soy and whey protein bar products both
similar increases in muscle protein net balance, resulting in net promoted exercise training-induced lean body mass gain, but
muscle protein synthesis despite different patterns of blood the soy had the added benefit of preserving two aspects of
amino acid responses. antioxidant function.
Int J Sport Nutr Exerc Metab. 2004 Jun;14(3):255-71. Int J Sport Nutr Exerc Metab. 2001 Sep;11(3):349-64.
Effect of an amino acid, protein, and carbohydrate mixture on The effect of whey protein supplementation with and without
net muscle protein balance after resistance exercise. creatine monohydrate combined with resistance training on
Borsheim E, Aarsland A, Wolfe RR. lean tissue mass and muscle strength.
This study tests the hypotheses that (a) a mixture of whey Burke DG, Chilibeck PD, Davidson KS, Candow DG, Farthing
protein, amino acids (AA), and carbohydrates (CHO) J, Smith-Palmer T.
stimulates net muscle protein synthesis to a greater extent Our purpose was to assess muscular adaptations during 6
than isoenergetic CHO alone after resistance exercise; and (b) weeks of resistance training in 36 males randomly assigned to
that the stimulatory effect of a protein, AA, and CHO mixture supplementation with whey protein (W; 1.2 g/kg/day), whey
will last beyond the 1st hour after intake. Eight subjects protein and creatine monohydrate (WC; 0.1 g/kg/day), or
participated in 2 trials. In one (PAAC), they ingested 77.4 g placebo (P; 1.2 g/kg/day maltodextrin). Measures included
Strength, Speed, Body Composition / Page 14
lean tissue mass by dual energy x-ray absorptiometry, bench overall anticatabolic effects caused by the peptide
press and squat strength (1-repetition maximum), and knee components of the casein hydrolysate.
extension/flexion peak torque. Lean tissue mass increased to a
greater extent with training in WC compared to the other Med Sci Sports Exerc. 2006 Apr;38(4):667-74.
groups, and in the W compared to the P group (p < .05). Milk ingestion stimulates net muscle protein synthesis
Bench press strength increased to a greater extent for WC following resistance exercise.
compared to W and P (p < .05). Knee extension peak torque Elliot TA, Cree MG, Sanford AP, Wolfe RR, Tipton KD.
increased with training for WC and W (p < .05), but not for P. Metabolism Unit, Shriners Hospitals for Children and
All other measures increased to a similar extent across groups. Department of Surgery, The University of Texas Medical
Continued training without supplementation for an additional Branch, Galveston, TX, USA.
6 weeks resulted in maintenance of strength and lean tissue PURPOSE: Previous studies have examined the response of
mass in all groups. Males that supplemented with whey muscle protein to resistance exercise and nutrient ingestion.
protein while resistance training demonstrated greater Net muscle protein synthesis results from the combination of
improvement in knee extension peak torque and lean tissue resistance exercise and amino acid intake. No study has
mass than males engaged in training alone. Males that examined the response of muscle protein to ingestion of
supplemented with a combination of whey protein and protein in the context of a food. This study was designed to
creatine had greater increases in lean tissue mass and bench determine the response of net muscle protein balance
press than those who supplemented with only whey protein following resistance exercise to ingestion of nutrients as
or placebo. However, not all strength measures were improved components of milk. METHOD: Three groups of volunteers
with supplementation, since subjects who supplemented with ingested one of three milk drinks each: 237 g of fat-free milk
creatine and/or whey protein had similar increases in squat (FM), 237 g of whole milk (WM), and 393 g of fat-free milk
strength and knee flexion peak torque compared to subjects isocaloric with the WM (IM). Milk was ingested 1 h following
who received placebo. a leg resistance exercise routine. Net muscle protein balance
was determined by measuring amino acid balance across the
Ann Nutr Metab. 2000;44(1):21-9. leg. RESULTS: Arterial concentrations of representative
Effect of a hypocaloric diet, increased protein intake and amino acids increased in response to milk ingestion.
resistance training on lean mass gains and fat mass loss in Threonine balance and phenylalanine balance were both > 0
overweight police officers. following milk ingestion. Net amino acid uptake for threonine
Demling RH, DeSanti L. was 2.8-fold greater (P < 0.05) for WM than for FM. Mean
We compare the effects of a moderate hypocaloric, high- uptake of phenylalanine was 80 and 85% greater for WM and
protein diet and resistance training, using two different IM, respectively, than for FM, but not statistically different.
protein supplements, versus hypocaloric diet alone on body Threonine uptake relative to ingested was significantly (P <
compositional changes in overweight police officers. A 0.05) higher for WM (21 +/- 6%) than FM (11 +/- 5%), but not
randomized, prospective 12-week study was performed IM (12 +/- 3%). Mean phenylalanine uptake/ingested also was
comparing the changes in body composition produced by greatest for WM, but not significantly. CONCLUSIONS:
three different treatment modalities in three study groups. One Ingestion of milk following resistance exercise results in
group (n = 10) was placed on a nonlipogenic, hypocaloric diet phenylalanine and threonine uptake, representative of net
alone (80% of predicted needs). A second group (n = 14) was muscle protein synthesis. These results suggest that whole
placed on the hypocaloric diet plus resistance exercise plus a milk may have increased utilization of available amino acids
high-protein intake (1.5 g/kg/day) using a casein protein for protein synthesis.
hydrolysate. In the third group (n = 14) treatment was
identical to the second, except for the use of a whey protein J Am Coll Nutr. 2004 Aug;23(4):322-30.
hydrolysate. We found that weight loss was approximately 2.5 Effect of post-exercise supplement consumption on
kg in all three groups. Mean percent body fat with diet alone adaptations to resistance training.
decreased from a baseline of 27 +/- 1.8 to 25 +/- 1.3% at 12 Rankin JW, Goldman LP, Puglisi MJ, Nickols -Richardson SM,
weeks. With diet, exercise and casein the decrease was from Earthman CP, Gwazdauskas FC.
26 +/- 1.7 to 18 +/- 1.1% and with diet, exercise and whey Department of Human Nutrition, Foods, and Exercise, Virginia
protein the decrease was from 27 +/- 1.6 to 23 +/- 1.3%. The Tech, Blacksburg VA 24061-0430, USA. email@example.com
mean fat loss was 2. 5 +/- 0.6, 7.0 +/- 2.1 and 4.2 +/- 0.9 kg in OBJECTIVE: Athletes are interested in nutritional
the three groups, respectively. Lean mass gains in the three manipulations that may enhance lean tissue gains stimulated
groups did not change for diet alone, versus gains of 4 +/- 1.4 by resistance training. Some research demonstrates that acute
and 2 +/- 0.7 kg in the casein and whey groups, respectively. consumption of food containing protein causes superior
Mean increase in strength for chest, shoulder and legs was 59 muscle protein synthesis compared to isoenergetic foods
+/- 9% for casein and 29 +/- 9% for whey, a significant group without protein. This benefit has not been verified in longer-
difference. This significant difference in body composition term training studies. We compared body composition and
and strength is likely due to improved nitrogen retention and muscle function responses to resistance training in males who
consumed a carbohydrate or a multi-macronutrient beverage
Strength, Speed, Body Composition / Page 15
following each training session. METHODS: Nineteen, delivery associated with milk versus hydrolyzed soy proteins.
untrained men (18-25 years) consumed either a milk (MILK) or If our acute findings are accurate then we hypothesized that
a carbohydrate-electrolyte (CHO) drink immediately following chronically the greater net protein deposition associated with
each workout during a 10 week resistance training program. milk protein consumption post-resistance exercise would
Muscle strength (1RM for seven exercises), body eventually lead to greater net protein accretion (i.e., muscle
composition (DXA scan), fasted, resting concentrations of fiber hypertrophy), over a longer time period. In young men
serum total and free testosterone, cortisol, IGF-1, and resting completing 12 weeks of resistance training (5d/wk) we
energy expenditure (REE) were measured prior to and at the observed a tendency (P = 0.11) for greater gains in whole
end of training. RESULTS: Resistance training caused an body lean mass and whole as greater muscle fiber
increase (44 +/- 4%, p < 0.001) in muscular strength for all hypertrophy with consumption of milk. While strength gains
subjects. The training program reduced percent body fat (8%, were not different between the soy and milk-supplemented
p < 0.05, -0.9 +/- 0.5 kg) and increased fat-free soft tissue groups we would argue that the true significance of a greater
(FFST) mass (2%, 1.2 +/- 0.3 kg, p < 0.01). MILK tended to increase in lean mass that we observed with milk consumption
increase body weight and FFST mass (p = 0.10 and p = 0.13, may be more important in groups of persons with lower initial
respectively) compared to CHO. Resting total and free lean mass and strength such as the elderly.
testosterone concentrations decreased from baseline values
in all subjects (16.7%, 11%, respectively, p < 0.05). Significant Med Sci Sports Exerc. 2007 Feb;39(2):298-307.
changes in fasting IGF-1, cortisol, and REE across training Effects of whey isolate, creatine, and resistance training on
were not observed for either group. CONCLUSION: Post- muscle hypertrophy.
resistance exercise consumption of MILK and CHO caused Cribb PJ, Williams AD, Stathis CG, Carey MF, Hayes A.
similar adaptations to resistance training. It is possible that a Exercise Metabolism Unit, Center for Ageing, Rehabilitation,
more prolonged training with supplementation period would Exercise and Sport and the School of Biomedical Sciences,
expand the trend for greater FFST gains in MILK. Victoria University, Victoria, Australia.
PURPOSE: Studies that have attributed gains in lean body
Phillips SM, Hartman JW, Wilkinson SB. Dietary protein to mass to dietary supplementation during resistance exercise
support anabolism with resistance exercise in young men. J (RE) training have not reported these changes alongside
Am Coll Nutr. 2005 Apr;24(2):134S-139S. adaptations at the cellular and subcellular levels. Therefore,
Resistance exercise is fundamentally anabolic and as such the purpose of this study was to examine the effects of two
stimulates the process of skeletal muscle protein synthesis popular supplements--whey protein (WP) and creatine
(MPS) in an absolute sense and relative to skeletal muscle monohydrate (CrM) (both separately and in combination)--on
protein breakdown (MPB). However, the net effect of body composition, muscle strength, fiber-specific
resistance exercise is to shift net protein balance (NPB = MPS hypertrophy (i.e., type I, IIa, IIx), and contractile protein
- MPB) to a more positive value; however, in the absence of accrual during RE training. METHODS: In a double-blind
feeding NPB remains negative. Feeding stimulates MPS to an randomized protocol, resistance-trained males were matched
extent where NPB becomes positive, for a transient time. for strength and placed into one of four groups:
When combined, resistance exercise and feeding creatine/carbohydrate (CrCHO), creatine/whey protein
synergistically interact to result in NPB being greater than (CrWP), WP only, or carbohydrate only (CHO) (1.5 g x kg(-1)
with feeding alone. This feeding- and exercise-induced body weight per day). All assessments were completed the
stimulation of NPB is what, albeit slowly, results in muscle week before and after an 11-wk structured, supervised RE
hypertrophy. With this rudimentary knowledge we are now at program. Assessments included strength (1RM, three
the point where we can manipulate variables within the exercises), body composition (DEXA), and vastus lateralis
system to see what impact these interventions have on the muscle biopsies for determination of muscle fiber type (I, IIa,
processes of MPS, MPB, and NPB and ultimately and perhaps IIx), cross-sectional area (CSA), contractile protein, and
most importantly, muscle hypertrophy and strength. We used creatine (Cr) content. RESULTS: Supplementation with
established models of skeletal muscle amino acid turnover to CrCHO, WP, and CrWP resulted in significantly greater (P <
examine how protein source (milk versus soy) acutely affects 0.05) 1RM strength improvements (three of three
the processes of MPS and MPB after resistance exercise. Our assessments) and muscle hypertrophy compared with CHO.
findings revealed that even when balanced quantities of total Up to 76% of the strength improvements in the squat could be
protein and energy are consumed that milk proteins are more attributed to hypertrophy of muscle involved in this exercise.
effective in stimulating amino acid uptake and net protein However, the hypertrophy responses within these groups
deposition in skeletal muscle after resistance exercise than are varied at the three levels assessed (i.e., changes in lean mass,
hydrolyzed soy proteins. Importantly, the finding of increased fiber-specific hypertrophy, and contractile protein content).
amino acid uptake would be independent of the differences in CONCLUSIONS: Although WP and/or CrM seem to promote
amino acid composition of the two proteins. We propose that greater strength gains and muscle morphology during RE
the improved net protein deposition with milk protein training, the hypertrophy responses within the groups varied.
consumption is also not due to differences in amino acid These differences in skeletal muscle morphology may have
composition, but is due to a different pattern of amino acid
Strength, Speed, Body Composition / Page 16
important implications for various populations and, therefore, the PRE-POST group consumed a supplement (1 g x kg(-1)
warrant further investigation. body weight) containing protein/creatine/glucose immediately
before and after RE. The MOR-EVE group consumed the same
Int J Sport Nutr Exerc Metab. 2006 Oct;16(5):494-509. dose of the same supplement in the morning and late evening.
The effect of whey isolate and resistance training on strength, All assessments were completed the week before and after 10
body composition, and plasma glutamine. wk of structured, supervised RE training. Assessments
Cribb PJ, Williams AD, Carey MF, Hayes A. included strength (1RM, three exercises), body composition
Exercise Metabolism Unit, Center for Ageing, Rehabilitation, (DEXA), and vastus lateralis muscle biopsies for
Exercise and Sport (CARES), Australia. determination of muscle fiber type (I, IIa, IIx), cross -sectional
Different dietary proteins affect whole body protein anabolism area (CSA), contractile protein, creatine (Cr), and glycogen
and accretion and therefore, have the potential to influence content. RESULTS: PRE-POST demonstrated a greater (P <
results obtained from resistance training. This study examined 0.05) increase in lean body mass and 1RM strength in two of
the effects of supplementation with two proteins, hydrolyzed three assessments. The changes in body composition were
whey isolate (WI) and casein (C), on strength, body supported by a greater (P < 0.05) increase in CSA of the type
composition, and plasma glutamine levels during a 10 wk, II fibers and contractile protein content. PRE-POST
supervised resistance training program. In a double-blind supplementation also resulted in higher muscle Cr and
protocol, 13 male, recreational bodybuilders supplemented glycogen values after the training program (P < 0.05).
their normal diet with either WI or C (1.5 gm/kg body wt/d) for CONCLUSION: Supplement timing represents a simple but
the duration of the program. Strength was assessed by 1-RM effective strategy that enhances the adaptations desired from
in three exercises (barbell bench press, squat, and cable pull- RE-training.
down). Body composition was assessed by dual energy X-ray
absorptiometry. Plasma glutamine levels were determined by Creatine
the enzymatic method with spectrophotometric detection. All Int J Sport Nutr Exerc Metab. 2003 Jun;13(2):198-226.
assessments occurred in the week before and the week Effect of creatine supplementation on body composition and
following 10 wk of training. Plasma glutamine levels did not performance: a meta-analysis.
change in either supplement group following the intervention. Branch JD.
The WI group achieved a significantly greater gain (P < 0.01) Department of Exercise Science, Physical Education, and
in lean mass than the C group (5.0 +/- 0.3 vs. 0.8 +/- 0.4 kg for Recreation at Old Dominion University, Norfolk, VA 23529-
WI and C, respectively) and a significant (P < 0.05) change in 0196, USA.
fat mass (-1.5 +/- 0.5 kg) compared to the C group (+0.2 +/- 0.3 BACKGROUND: Creatine supplementation (CS) has been
kg). The WI group also achieved significantly greater (P < reported to increase body mass and improve performance in
0.05) improvements in strength compared to the C group in high-intensity, short-duration exercise tasks. Research on CS,
each assessment of strength. When the strength changes most of which has come into existence since 1994, has been
were expressed relative to body weight, the WI group still the focus of several qualitative reviews, but only one meta-
achieved significantly greater (P < 0.05) improvements in analysis, which was conducted with a limited number of
strength compared to the C group. studies. PURPOSE: This study compared the effects of CS on
effect size (ES) for body composition (BC) variables (mass and
Med Sci Sports Exerc. 2006 Nov;38(11):1918-25. lean body mass), duration and intensity (< or = 30 s, [ATP-PCr
Effects of supplement timing and resistance exercise on = A]; 30-150 s [glycolysis = G]; >150 s, [oxidative
skeletal muscle hypertrophy. phosphorylation = O]) of the exercise task, type of exercise
Cribb PJ, Hayes A. task (single, repetitive, laboratory, field, upper-body, lower-
Exercise Metabolism Unit, Center for Ageing, Rehabilitation, body), CS duration (loading, maintenance), and subject
Exercise and Sport; and the School of Biomedical Sciences, characteristics (gender, training status). METHODS: A search
Victoria University, Melbourne, Victoria, Australia. of MEDLINE and SPORTDiscus using the phrase "creatine
PURPOSE: Some studies report greater muscle hypertrophy supplementation" revealed 96 English-language, peer-
during resistance exercise (RE) training from supplement reviewed papers (100 studies), which included randomized
timing (i.e., the strategic consumption of protein and group formation, a placebo control, and human subjects who
carbohydrate before and/or after each workout). However, no were blinded to treatments. ES was calculated for each body
studies have examined whether this strategy provides greater composition and performance variable. RESULTS: Small, but
muscle hypertrophy or strength development compared with significant (ES > 0, p < or = .05) ES were reported for BC
supplementation at other times during the day. The purpose (n=163, mean +/- SE=0.17 +/- 0.03), ATP-PCr (n=17, 0.24 +/-
of this study was to examine the effects of supplement timing 0.02), G (n=135, 0.19 +/- 0.05), and O (n=69, 0.20 +/- 0.07). ES
compared with supplementation in the hours not close to the was greater for change in BC following a loading-only CS
workout on muscle-fiber hypertrophy, strength, and body regimen (0.26 +/- 0.03, p=.0003) compared to a maintenance
composition during a 10-wk RE program. METHODS: In a regimen (0.04 +/- 0.05), for repetitive-bout (0.25 +/- 0.03,p=.028)
single-blind, randomized protocol, resistance-trained males compared to single-bout (0.18 +/- 0.02) exercise, and for upper-
were matched for strength and placed into one of two groups; body exercise (0.42 +/- 0.07, p<.0001) compared to lower (0.21
Strength, Speed, Body Composition / Page 17
+/- 0.02) and total body (0.13 +/- 0.04) exercise. ES for performance outcomes rather than on proposed mechanisms
laboratory-based tasks (e.g., isometric/isotonic/isokinetic of action. The last brief section of this review deals with the
exercise, 0.25 +/- 0.02) were greater (p=.014) than those potential adverse effects of Cr supplementation. There
observed for field-based tasks (e.g., running, swimming, 0.14 appears to be no strong scientific evidence to support any
+/- 0.04). There were no differences in BC or performance ES adverse effects but it should be noted that there have been no
between males and females or between trained and untrained studies to date that address the issue of long-term Cr usage.
subjects. CONCLUSION: ES was greater for changes in lean
body mass following short-term CS, repetitive-bout Chilibeck PD, Stride D, Farthing JP, Burke DG. Effect of
laboratory-based exercise tasks < or = 30 s (e.g., isometric, creatine ingestion after exercise on muscle thickness in males
isokinetic, and isotonic resistance exercise), and upper-body and females. Med Sci Sports Exerc. 2004 Oct;36(10):1781-8.
exercise. CS does not appear to be effective in improving College of Kinesiology, University of Saskatchewan,
running and swimming performance. There is no evidence in Saskatoon, SK, Canada. firstname.lastname@example.org
the literature of an effect of gender or training status on ES Muscles exercised before creatine (Cr) supplementation have
following CS. a greater elevation of intramuscular Cr than nonexercised
muscles. PURPOSE: To determine whether preferential
Bemben MG, Lamont HS. Creatine supplementation and increase of muscle thickness could be achieved by ingesting
exercise performance: recent findings. Cr immediately after exercise of specific muscles over 6 wk.
Sports Med. 2005;35(2):107-25. Another purpose was to determine if the increase in lean
Creatine monohydrate (Cr) is perhaps one of the most widely tissue mass (LTM) with Cr supplementation is greater in males
used supplements taken in an attempt to improve athletic than females. METHODS: Subjects randomly assigned to Cr
performance. The aim of this review is to update, summarise (six males, five females, 0.2 g Cr x kg(-1)) and placebo (PL; five
and evaluate the findings associated with Cr inges tion and males, five females) performed single-limb training with one
sport and exercise performance with the most recent research side of the body two times per week and with the opposite
available. Because of the large volume of scientific literature limbs two times per week. Cr was consumed after training of
dealing with Cr supplementation and the recent efforts to one side of the body and PL after training the opposite side.
delineate sport-specific effects, this paper focuses on Subjects on PL always consumed PL after exercise. Elbow
research articles that have been published since 1999.Cr is flexors and knee extensors muscle thickness, LTM, fat, and
produced endogenously by the liver or ingested from bone mass, and single-limb bench and leg press one-
exogenous sources such as meat and fish. Almost all the Cr in repetition maximum (1-RM) were assessed before and after 6
the body is located in skeletal muscle in either the free (Cr: wk. RESULTS: Within the Cr group, elbow flexors muscle
approximately 40%) or phosphorylated (PCr: approximately thickness increased more in the limbs trained on days Cr was
60%) form and represents an average Cr pool of about 120-140 supplemented compared with limbs trained on days PL was
g for an average 70 kg person. It is hypothesised that Cr can supplemented (P < 0.02). All other measures changed to a
act though a number of possible mechanisms as a potential similar extent between limbs. Males on Cr had the greatest
ergogenic aid but it appears to be most effective for activities increase in LTM (P < 0.05) with no difference between females
that involve repeated short bouts of high-intensity physical on Cr and PL. Bench press 1-RM increased more in Cr than PL
activity. Additionally, investigators have studied a number of groups (P < 0.01). All other measures changed to a similar
different Cr loading programmes; the most common extent between groups. Males increased bone mass (P < 0.01)
programme involves an initial loading phase of 20 g/day for 5- with no effect of Cr supplementation. CONCLUSION:
7 days, followed by a maintenance phase of 3-5 g/day for Supplementing with Cr after training of the arms resulted in
differing periods of time (1 week to 6 months). When maximal greater increase in muscle thickness of the arms. Males have
force or strength (dynamic or isotonic contractions) is the a greater increase in LTM with Cr supplementation than
outcome measure following Cr ingestion, it generally appears females.
that Cr does significantly impact force production regardless
of sport, sex or age. The evidence is much more equivocal J Strength Cond Res. 2003 Nov;17(4):822-31.
when investigating isokinetic force production and little Effects of creatine supplementation and resis tance training on
evidence exists to support the use of Cr for isometric muscle strength and weightlifting performance.
muscular performance. There is little benefit from Cr Rawson ES, Volek JS.
ingestion for the prevention or suppression of muscle Department of Exercise Science and Athletics, Bloomsburg
damage or soreness following muscular activity. When University, Bloomsburg, Pennsylvania 17815, USA.
performance is assessed based on intensity and duration of email@example.com
the exercises, there is contradictory evidence relative to both Creatine monohydrate has become the supplement of choice
continuous and intermittent endurance activities. However, for many athletes striving to improve sports performance.
activities that involve jumping, sprinting or cycling Recent data indicate that athletes may not be using creatine
generally show improved sport performance following Cr as a sports performance booster per se but instead use
ingestion. With these concepts in mind, the focus of this creatine chronically as a training aid to augment intense
paper is to summarise the effectiveness of Cr on specific resistance training workouts. Although several studies have
Strength, Speed, Body Composition / Page 18
evaluated the combined effects of creatine supplementation possibility that a low dose of Cr may be an effective means of
and resistance training on muscle strength and weightlifting enhancing performance after short-term ingestion.
performance, these data have not been analyzed collectively.
The purpose of this review is to evaluate the effects of J Strength Cond Res. 2003 Feb;17(1):26-33.
creatine supplementation on muscle strength and Creatine supplementation and its effect on musculotendinous
weightlifting performance when ingested concomitant with stiffness and performance.
resistance training. The effects of gender, interindividual Watsford ML, Murphy AJ, Spinks WL, Walshe AD.
variability, training status, and possible mechanisms of action Human Movement Department, School of Leisure, Sport, and
are discussed. Of the 22 studies reviewed, the average Tourism, University of Technology, Sydney, Australia 2070.
increase in muscle strength (1, 3, or 10 repetition maximum firstname.lastname@example.org
[RM]) following creatine supplementation plus resistance Anecdotal reports suggesting that creatine (Cr)
training was 8% greater than the average increase in muscle supplementation may cause side effects, such as an increased
strength following placebo ingestion during resistance incidence of muscle strains or tears, require scientific
training (20 vs. 12%). Similarly, the average increase in examination. In this study, it was hypothesized that the rapid
weightlifting performance (maximal repetitions at a given fluid retention and "dry matter growth" evident after Cr
percent of maximal strength) following creatine supplementation may cause an increase in musculotendinous
supplementation plus resistance training was 14% greater stiffness. Intuitively, an increase in musculotendinous
than the average increase in weightlifting performance stiffness would increase the chance of injury during exercise.
following placebo ingestion during resistance training (26 vs. Twenty men were randomly allocated to a control or an
12%). The increase in bench press 1RM ranged from 3 to 45%, experimental group and were examined for musculotendinous
and the improvement in weightlifting performance in the stiffness of the triceps surae and for numerous performance
bench press ranged from 16 to 43%. Thus there is substantial indices before and after Cr ingestion. The Cr group achieved a
evidence to indicate that creatine supplementation during significant increase in body mass (79.7 +/- 10.8 kg vs. 80.9 +/-
resistance training is more effective at increasing muscle 10.7 kg), counter movement jump height (40.2 +/- 4.8 cm vs.
strength and weightlifting performance than resistance 42.7 +/- 5.9 cm), and 20-cm drop jump height (32.3 +/- 3.3 cm
training alone, although the response is highly variable. vs. 35.1 +/- 4.8 cm) after supplementation. No increase was
found for musculotendinous stiffness at any assessment load.
J Strength Cond Res. 2004 May;18(2):311-5. There were no significant changes in any variables within the
Mg2+-creatine chelate and a low-dose creatine control group. These findings have both performance- and
supplementation regimen improve exercise performance. injury-related implications. Primarily, anecdotal evidence
Selsby JT, DiSilvestro RA, Devor ST. suggesting that Cr supplementation causes muscular strain
Section of Sport and Exercise Sciences, The Ohio State injuries is not supported by this study. In addition, the
University, Columbus, Ohio 43210, USA. increase in jump performance is indicative of performance
We tested the hypotheses that, compared with a placebo enhancement in activities requiring maximal power output.
group or creatine (Cr) group, a Mg(2+)-Cr chelate group
would demonstrate improvements in the 1 repetition maximum J Athl Train. 2003 Sep;38(3):216-219.
(1RM) on the bench press and be able to perform more work Cramping and Injury Incidence in Collegiate Football Players
at 70% of the 1RM for the bench press. Thirty-one weight- Are Reduced by Creatine Supplementation.
trained men were randomly assigned in a double-blind manner Greenwood M, Kreider RB, Greenwood L, Byars A.
to a placebo group (multidextran), a Cr group (2.5 g of Cr Baylor University, Waco, TX.
daily), or a Mg(2+)-Cr group (2.5 g of Cr daily). Baseline data OBJECTIVE: To examine the effects of creatine
were collected for the bench press 1RM and maximal work supplementation on the incidence of cramping and injury
completed during a fatigue set at 70% of the 1RM. Following observed during 1 season of National Collegiate Athletic
10 days of Cr supplementation, follow-up tests were Association Division IA football training and competition.
completed for the dependent variables. Groups were similar DESIGN AND SETTING: In an open-label manner, subjects
when the change in 1RM was evaluated either absolutely or who volunteered to take creatine ingested 0.3 g.kg(-1).d(-1) of
relatively. Both the Cr and the Mg(2+)-Cr groups had creatine for 5 days followed by an average of 0.03 g.kg.(-1)d(-
significantly larger increases in work, both absolutely and 1) after workouts, practices, and games. Creatine intake was
relatively, when compared with the placebo group. Partial monitored and recorded by researchers throughout the course
support for the hypothesis suggests that low doses of Cr are of the study. SUBJECTS: Thirty-eight of 72 athletes (53.0%)
effective at increasing fiber Cr content, and consequently, participating in the 1999 Division IA collegiate football season
performance. Further, the Cr and Mg(2+)-Cr groups were from the same university volunteered to take creatine in this
similar in both performance tests, suggesting that the study. Subjects trained, practiced, or played in environmental
proposed mechanism of entry is no better than the conditions ranging from 15 degrees C to 37 degrees C (mean =
conventional method when 2.5 g of Cr is administered and 27.26 degrees +/- 10.93 degrees C) and 46.0% to 91.0% relative
performance is measured as work. This study raises the humidity (mean = 54.17% +/- 9.71%). MEASUREMENTS:
Injuries treated by the athletic training staff were recorded and
Strength, Speed, Body Composition / Page 19
categorized as cramping, heat illness or dehydration, muscle Creatine supplementation does not appear to increase the
tightness, muscle strains, noncontact joint injuries, contact incidence of injury or cramping in Division IA college football
injuries, and illness. The number of missed practices due to players.
injury and illness was also recorded. Data were analyzed
using a 2 x 2 chi(2) test to examine the first reported Int J Sport Nutr Exerc Metab. 2003 Mar;13(1):97-111.
incidences of cramping and injury for creatine users and Creatine supplementation: a comparison of loading and
nonusers. RESULTS: Creatine users had significantly less maintenance protocols on creatine uptake by human skeletal
cramping (chi(2)(1) = 5.35 P =.021); heat illness or dehydration muscle.
(chi(2)(1) = 4.09, P =.043); muscle tightness (chi(2)(1) = 5.39, P Preen D, Dawson B, Goodman C, Beilby J, Ching S.
=.020); muscle strains (chi(2)(1) = 5.36, P =.021); and total Department of Human Movement and Exercise Science at The
injuries (chi(2)(1) = 17.80, P<.001) than nonusers. There were University of Western Australia, Crawley, W.A., Australia,
no significant differences between groups regarding 6009.
noncontact joint injuries (chi(2)(1)= 3.48, P =.062); contact The purposes of this investigation were first to determine the
injuries (chi(2)(1) = 0.00, P =.100); illness (chi(2)(1) = 6.82, P impact of 3 different creatine (Cr) loading procedures on
=.409); missed practices due to injury (chi(2)(1) = 1.43, P skeletal muscle total Cr (TCr) accumulation and, second, to
=.233); or players lost for the season (chi(2)(1) = 4.75, P =.491). evaluate the effectiveness of 2 maintenance regimes on
CONCLUSIONS: The incidence of cramping or injury in retaining intramuscular TCr stores, in the 6 weeks following a
Division IA football players was significantly lower or 5-day Cr loading program (20 g x day(-1). Eighteen physically
proportional for creatine users compared with nonusers. active male subjects were divided into 3 equal groups and
administered either: (a) Cr (4 x 5 g x day(-1) x 5 days), (b)
Mol Cell Biochem. 2003 Feb;244(1-2):83-8. Glucose+Cr (1 g x (-1) of body mass twice per day), or (c) Cr in
Creatine supplementation during college football training conjunction with 60 min of daily muscular (repeated-sprint)
does not increase the incidence of cramping or injury. exercise. Following the 5-day loading period, subjects were
Greenwood M, Kreider RB, Melton C, Rasmussen C, reassigned to 3 maintenance groups and ingested either 0 g x
Lancaster S, Cantler E, Milnor P, Almada A. day(-1), 2 g. day(-1) or 5 g x day(-1) of Cr for a period of 6
Human Performance Laboratory, Department of HPESS, weeks. Muscle biopsy samples (vastus lateralis) were taken
Arkansas State University, Jonesboro, AR, USA. pre- and post-loading as well as post-maintenance and
The purpose of this study was to examine the effects of analyzed for skeletal muscle ATP, phosphocreatine (PCr), Cr,
creatine supplementation on the incidence of injury observed and TCr concentrations. Twenty-four hour urine samples were
during 3-years of NCAA Division IA college football training collected for each of the loading days and last 2 maintenance
and competition. In an open label manner, athletes days, and used to determine whole body Cr retention. Post-
participating in the 1998-2000 football seasons elected to take loading TCr stores were significantly (p <.05) increased in all
creatine or non-creatine containing supplements following treatment conditions. The Glucose+Cr condition produced a
workouts/practices. Subjects who decided to take creatine greater elevation (p <.05) in TCr concentrations (25%) than
were administered 15.75 g of creatine for 5 days followed by the Cr Only (16%) or Exercise+Cr (18%) groups. Following the
ingesting an average of 5 g/day thereafter administered in 5-10 maintenance period, muscle TCr stores were still similar to
g doses. Creatine intake was monitored and recorded by post-loading values for both the 2 g x day(-1) and 5 g x day(-1)
research assistants throughout the study and ranged between conditions. Intramuscular TCr values for the 0 g x day(-1)
34-56% of players during the course of the study. Subjects condition were significantly lower than the other conditions
practiced or played in environmental conditions ranging from after the 6-week period. Although not significantly different
8-40 degrees C (mean 24.7 +/- 9 degrees C) and 19-98% relative from pre-loading concentrations, muscle TCr for the 0 g x
humidity (49.3 +/- 17%). Injuries treated by the athletic day(-1) group had not fully returned to baseline levels at 6
training staff were recorded and categorized as cramping, weeks post-loading. The data suggests that Glucose+Cr (but
heat/dehydration, muscle tightness, muscle strains/pulls, with a much smaller glucose intake than currently accepted) is
noncontact joint injuries, contact injuries, and illness. The potentially the most effective means of elevating TCr
number of missed practices due to injury/illness was also accumulation in human skeletal muscle. Furthermore, after 5
recorded. Data are presented as the total number of treated days of Cr loading, elevated muscle TCr concentrations can
injuries for creatine users/total injuries observed and be maintained by the ingestion of small daily Cr doses (2-5 g)
percentage occurrence rate of injuries for creatine users for all for a period of 6 weeks and that TCr concentrations may take
seasons. The incidence of cramping (37/96, 39%), longer than currently accepted to return to baseline values
heat/dehydration (8/28, 36%), muscle tightness (18/42, 43%), after such a Cr loading regime.
muscle pulls/strains (25/51, 49%), non-contact joint injuries
(44/132, 33%), contact injuries (39/104, 44%), illness (12/27, Int J Sport Nutr Exerc Metab. 2003 Jun;13(2):173-83.
44%), number of missed practices due to injury (19/41, 46%), Effect of creatine supplementation on aerobic performance
players lost for the season (3/8, 38%), and total and anaerobic capacity in elite rowers in the course of
injuries/missed practices (205/529, 39%) were generally lower endurance training.
or proportional to the creatine use rate among players. Chwalbinska-Moneta J.
Strength, Speed, Body Composition / Page 20
Department of Applied Physiology in the Medical Research lean tissue, and total work performance than nonvegetarians
Centre of Polish Academy of Sciences, 02-106 Warsaw, who took Cr (P<0.05). The change in muscle TCr was
Poland. significantly correlated with initial muscle TCr, and the change
The effect of oral creatine supplementation on aerobic and in lean tissue mass and exercise performance. These findings
anaerobic performance was investigated in 16 elite male confirm an ergogenic effect of Cr during resistance training
rowers during 7-day endurance training. Before and after the and suggest that subjects with initially low levels of
daily ingestion of 20 g creatine monohydrate for 5 days (Cr- intramuscular Cr (vegetarians) are more responsive to
Group, n=8) or placebo (Pl-Group, n=8), subjects performed supplementation.
two exercise tests on a rowing ergometer: (a) incremental
exercise consisting of 3-min stage durations and increased by J Sports Med Phys Fitness. 2003 Sep;43(3):347-55.
50 W until volitional exhaus tion; (b) an all-out anaerobic Creatine supplementation: effects on urinary excretion and
exercise performed against a constant load of 7 W/kg. Heart anaerobic performance.
rate and blood lactate concentrations were determined during Havenetidis K, Bourdas D.
exercise and recovery. Maximal power output did not Hellenic Army Academy, Athens, Hellas, Greece.
significantly differ after the treatment in either group. The AIM: The aim of the present study is to investigate Urinary
mean individual lactate threshold rose significantly after Cr creatine (URCR) and urinary creatinine (URCRN) response to
treatment from 314.3 +/- 5.0 W to 335.6 +/- 7.1 W (p<.01), as CR supplementation in conjunction with exercise performance.
compared with 305.0 +/- 6.9 W and 308.9 +/- 5.9 W (ns), before METHODS: Twenty-one sprint trained males were randomly
and after placebo ingestion, respectively. During the divided into 3 groups. Each group followed a different CR
anaerobic test, the athletes supplemented with creatine were dosage (10 g, 25 g and 35 g x day(-1) for 4 days) and placebo
able to continue rowing longer (mean increase, 12.1 +/- 4.5 s; (Pl) in the 1(st) and 2(nd) week, respectively. A double-blind
p<.01) than Pl-Group (2.4 +/- 8.2 s; ns). No significant design was used. Subjects' urine was collected every 24 hours
differences were found between groups in blood LA after the during the entire period of supplementation (SP). All groups,
all-out exercise. The results indicate that in elite rowers, at the end of each SP performed 3 times the Anaerobic
creatine supplementation improves endurance (expressed by Wingate Test (AWT) with 6 min active recovery (60 rpm) on a
the individual lactate threshold) and anaerobic performance, cycle ergometer. RESULTS: Significantly (p<0.01) higher peak
independent of the effect of intensive endurance training. and mean power values were produced during the CR
compared to Pl condition. A significant correlation (r=0.7,
Med Sci Sports Exerc. 2003 Nov;35(11):1946-55. p<0.05) was also observed between peak power improvement
Effect of creatine and weight training on muscle creatine and (PPI) and URCR for the 3 groups. No such relationship was
performance in vegetarians. found between URCRN. Across all groups, URCR and
Burke DG, Chilibeck PD, Parise G, Candow DG, Mahoney D, URCRN increased significantly following ingestion compared
Tarnopolsky M. with Pl (p<0.001). URCR post- supplementation presented a
Department of Human Kinetics, St. Francis Xavier University, 7.4 fold, 36 fold and 21 fold increase for 10 g, 25 g and 35 g
Antigonish, Nova Scotia, Canada. email@example.com dose respectively, whilst URCRN presented a mean 2.4 fold
PURPOSE: To compare the change in muscle creatine, fiber increase for all different doses, which clearly shows the
morphology, body composition, hydration status, and magnitude of sensitivity of these indices to CR
exercise performance between vegetarians and supplementation. A strong correlation (r=0.95, p<0.01)
nonvegetarians with 8 wk of creatine supplementation and observed between dose of CR ingestion and mean URCR
resistance training. METHODS: Eighteen VG and 24 NV (MRUCR) with prediction formula: CR = -0.936 + (5.613 x
subjects (19-55 yr) were randomly assigned (double blind) to MRUCR) (SEE=3.5). CONCLUSION: URCR was an effective
four groups: VG + creatine (VGCr, N=10), VG + placebo (VGPl, measure of each CR dosage administered as well as of the
N=8), NV + creatine (NVCr, N=12), and NV + placebo (NVPl, excretion pattern that each group followed throughout the SP.
N=12). Before and at the end of the study, muscle biopsies Furthermore the strong relationship of URCR and PPI could
were taken from the vastus lateralis m, body composition was be particularly useful for monitoring and optimising CR
assessed by DXA, and strength was assessed using 1-RM loading in athletic populations.
bench press and leg press. Subjects participated in the same
8-wk resistance-training program. Creatine dosage was based J Strength Cond Res. 2004 Feb;18(1):168-73.
on lean tissue mass (0.25 g.kg(-1) LTM.d(-1) x 7 d; 0.0625 Effect of two and five days of creatine loading on anaerobic
g.kg(-1) LTM.d(-1) x 49 d). RESULTS: Biopsy samples working capacity in women.
indicated that total creatine (TCr=free Cr + PCr) was Eckerson JM, Stout JR, Moore GA, Stone NJ, Nishimura K,
significantly lower in VG compared with NV at baseline Tamura K.
(VG=117 mmol.kg(-1); NV=130 mmol.kg(-1); P<0.05). For Cr Department of Exercise Science and Athletic Training,
subjects, there was a greater increase in PCr, TCr, bench-press Creighton University, Omaha, NE 68178, USA.
strength, isokinetic work, Type II fiber area, and whole-body firstname.lastname@example.org
lean tissue compared with subjects on placebo (P<0.05). The purpose of this study was to determine the effects of 2
Vegetarians who took Cr had a greater increase in TCr, PCr, and 5 days of Cr loading on anaerobic working capacity
Strength, Speed, Body Composition / Page 21
(AWC) using the critical power (CP) test in women. Ten health status in athletes undergoing intense training in
physically active women randomly received 2 treatments comparison to athletes who do not take creatine.
separated by a 5 week washout period: (A) 18 g dextrose as J Strength Cond Res. 2004 Feb;18(1):162-7.
placebo (PL) or (B) 5.0 g Cr + 18 g dextrose taken 4 times per Effects of repeated creatine supplementation on muscle,
day for 5 days. Following a familiarization trial, each subject plasma, and urine creatine levels.
completed the CP test at baseline and following 2 and 5 days Rawson ES, Persky AM, Price TB, Clarkson PM.
of supplementation. The PL resulted in no significant changes Department of Exercise Science, University of Massachusetts,
in AWC following supplementation; however, Cr increased Amherst, Massachusetts 01003, USA. email@example.com
AWC by 22.1% after 5 days of loading (p < 0.05). There was a The purpose of this case study was to examine the effects of
significant main effect for body weight (BW), however, there repeated creatine administration on muscle phosphocreatine,
was no significant increase in BW due to Cr supplementation. plasma creatine, and urine creatine. One male subject (age, 32
These results suggest that Cr supplementation is effective for years; body mass, 78.4 kg; height, 160 cm; resistance training
increasing AWC in women following 5 days of loading experience, 15 years) ingested creatine (20 g.d(-1) for 5 days)
without an associated increase in BW. during 2 bouts separated by a 30-day washout period. Muscle
phosphocreatine was measured before and after
Mol Cell Biochem. 2003 Feb;244(1-2):95-104. supplementation. On day 1 of supplementation, blood
Long-term creatine supplementation does not significantly samples were taken immediately before and hourly for 5 hours
affect clinical markers of health in athletes. following ingestion of 5 g of creatine, and a pharmacokinetic
Kreider RB, Melton C, Rasmussen CJ, Greenwood M, analysis of plasma creatine was conducted. Twenty-four-hour
Lancaster S, Cantler EC, Milnor P, Almada AL. urine collections were conducted before and for 5 days during
Exercise and Sport Nutrition Laboratory, Department of supplementation. Muscle phosphocreatine increased 45%
Human Movement Sciences and Education, The University of following the first supplementation bout, decreased 22%
Memphis, Memphis, TN, USA. Richard_Kreider@baylor.edu during the 30-day washout period, and increased 25%
Creatine has been reported to be an effective ergogenic aid for following the second bout. There were no meaningful
athletes. However, concerns have been raised regarding the differences in plasma creatine pharmacokinetic parameters
long-term safety of creatine supplementation. This study between bouts 1 and 2. Total urine creatine losses during
examined the effects of long-term creatine supplementation on supplementation were 63.2 and 63.4 g during bouts 1 and 2,
a 69-item panel of serum, whole blood, and urinary markers of respectively. The major findings were that (a) a 30-day
clinical health status in athletes. Over a 21-month period, 98 washout period is insufficient time for muscle
Division IA college football players were administered in an phosphocreatine to return to baseline following creatine
open label manner creatine or non-creatine containing supplementation but is sufficient time for plasma and urine
supplements following training sessions. Subjects who creatine levels to return to presupplementation values; (b)
ingested creatine were administered 15.75 g/day of creatine postsupplementation muscle phosphocreatine levels were
monohydrate for 5 days and an average of 5 g/day thereafter similar following bouts 1 and 2 despite 23% higher
in 5-10 g/day doses. Fasting blood and 24-h urine samples presupplementation muscle phosphocreatine before bout 2;
were collected at 0, 1, 1.5, 4, 6, 10, 12, 17, and 21 months of and (c) the increased muscle phosphocreatine that persisted
training. A comprehensive quantitative clinical chemistry throughout the 30-day washout period corresponded with
panel was determined on serum and whole blood samples maintenance of increased body mass (+2.0 kg). Athletes
(metabolic markers, muscle and liver enzymes, electrolytes, should be aware that the washout period for muscle creatine
lipid profiles, hematological markers, and lymphocytes). In to return to baseline levels may be longer than 30 days in
addition, urine samples were quantitatively and qualitative some individuals, and this may be accompanied by a
analyzed to assess clinical status and renal function. At the persistent increase in body mass.
end of the study, subjects were categorized into groups that
did not take creatine (n = 44) and subjects who took creatine J Appl Physiol. 2003 Aug;95(2):818-28. Epub 2003 Mar 28.
for 0-6 months (mean 4.4 +/- 1.8 months, n = 12), 7-12 months Effects of creatine supplementation and exercise training on
(mean 9.3 +/- 2.0 months, n = 25), and 12-21 months (mean 19.3 fitness in men 55-75 yr old.
+/- 2.4 months, n = 17). Baseline and the subjects' final blood Eijnde BO, Van Leemputte M, Goris M, Labarque V, Taes Y,
and urine samples were analyzed by MANOVA and 2 x 2 Verbessem P, Vanhees L, Ramaekers M, Vanden Eynde B, Van
repeated measures ANOVA univariate tests. MANOVA Schuylenbergh R, Dom R, Richter EA, Hespel P.
revealed no significant differences (p = 0.51) among groups in Exercise Physiology and Biomechanics Laboratory, Faculty of
the 54-item panel of quantitative blood and urine markers Physical Education and Physiotherapy, KU Leuvrn, B-3001
assessed. Univariate analysis revealed no clinically significant Leuven, Belgium.
interactions among groups in markers of clinical status. In The effect of oral creatine supplementation (CR; 5 g/day) in
addition, no apparent differences were observed among conjunction with exercise training on physical fitness was
groups in the 15-item panel of qualitative urine markers. investigated in men between 55 and 75 yr of age (n = 46). A
Results indicate that long-term creatine supplementation (up double-blind randomized placebo-controlled (PL) trial was
to 21-months) does not appear to adversely effect markers of performed over a 6-mo period. Furthermore, a subgroup (n =
Strength, Speed, Body Composition / Page 22
20) completed a 1-yr follow-up. The training program measured thigh, and total body weight did not change for
consisted of cardiorespiratory endurance training as well as both groups between trials. We conclude that CrH2O
moderate resistance training (2-3 sessions/wk). Endurance improves muscle performance in women without significant
capacity was evaluated during a maximal incremental bicycle gains in muscle volume or body weight.
ergometer test, maximal isometric strength of the knee-
extensor muscles was assessed by an isokinetic J Gerontol A Biol Sci Med Sci. 2003 Jan;58(1):11-9.
dynamometer, and body composition was assessed by Creatine supplementation enhances isometric strength and
hydrostatic weighing. Furthermore, in a subgroup (PL: n = 13; body composition improvements following strength exercise
CR: n = 12) biopsies were taken from m. vastus lateralis to training in older adults.
determine total creatine (TCr) content. In PL, 6 mo of training Brose A, Parise G, Tarnopolsky MA.
increased peak oxygen uptake rate (+16%; P < 0.05). Fat-free Department of Kinesiology, McMaster University, Ontario,
mass slightly increased (+0.3 kg; P < 0.05), whereas percent Canada.
body fat slightly decreased (-1.2%; P < 0.05). The training We sought to determine whether creatine monohydrate (CrM)
intervention did not significantly change either maximal supplementation would enhance the increases in strength and
isometric strength or body weight. The responses were fat-free mass that develop during resistance exercise training
independent of CR. Still, compared with PL, TCr was increased in older adults. Twenty-eight healthy men and women over
by approximately 5% in CR, and this increase was closely the age of 65 years participated in a whole-body resistance
correlated with initial muscle creatine content (r = -0.78; P < exercise program 3 days per week for 14 weeks. The study
0.05). After a 1-yr follow-up, muscle TCr was not higher in CR participants were randomly allocated, in a double-blind
than in PL. Furthermore, the other measurements were not fashion, to receive either CrM (5 g/d + 2 g of dextrose; n = 14)
affected by CR. It is concluded that long-term creatine intake or placebo (7 g of dextrose; n = 14). The primary outcome
(5 g/day) in conjunction with exercise training does not measurements included the following: total body mass, fat-
beneficially impact physical fitness in men between 55 and 75 free mass, one-repetition maximum strength for each body
yr of age. part, isometric knee extension, handgrip, and dorsiflexion
strength, chair stand performance, 30-m walk test, 14-stair
Int J Sport Nutr Exerc Metab. 2003 Mar;13(1):87-96. climb performance, muscle fiber type and area, and
Short-term creatine supplementation improves maximum intramuscular total creatine. Fourteen weeks of resistance
quadriceps contraction in women. exercise training resulted in significant increases in all
Kambis KW, Pizzedaz SK. measurements of strength and functional tasks and muscle
Department of Kinesiology at The College of William and fiber area for both groups (p <.05). CrM supplementation
Mary, Williamsburg, VA 23187-8795, USA. resulted in significantly greater increases in fat-free mass and
Creatine monohydrate (CrH2O) supplementation has been total body mass, as compared with placebo (p <.05). The CrM
demonstrated to increase skeletal muscle power output in group also showed a greater increase in isometric knee
men. However, its effect upon women is not as clearly extension strength in men and women, as compared with
defined. This study investigated the effect of oral creatine placebo (p <.05), and also greater gains in isometric
supplementation upon muscle function, thigh circumference, dorsiflexion strength (p <.05), but in men only. There was a
and body weight in women. Twenty-two consenting college- significant increase in intramuscular total creatine in the CrM
age women were assigned to 1 of 2 groups matched for group (p <.05). Finally, there were no significant side effects
dietary and exercise habits, phase of menstrual cycle, and fat- of treatment or exercise training. This study confirms that
free mass (FFM). After familiarization with testing procedures, supervised heavy resistance exercise training can safely
pretrial measures of muscle function (5 repetitions 60 deg x s(- increase muscle strength and functional capacity in older
1) and 50 repetitions 180 deg x s(-1) were conducted during adults. The addition of CrM supplementation to the exercise
maximal voluntary concentric contraction of the preferred stimulus enhanced the increase in total and fat-free mass, and
quadriceps muscle using an isokinetic dynamometer. Subjects gains in several indices of isometric muscle strength.
then ingested 0.5 g x kg(-1) FFM of either CrH2O or placebo
(one fourth dosage 4 times daily) in a double-blind design for Int J Sport Nutr Exerc Metab. 2004 Feb;14(1):95-103.
5 days. Resistance exercise was prohibited. After the Creatine supplementation in young soccer players.
ingestion phase was completed, all measures were repeated at Ostojic SM.
the same time of day as during pretrials. Statistical analysis Exercise and Sport Nutrition Laboratory, O.C.A. Sports
revealed time to peak torque in quadriceps extension Medicine Institute, Kikindska 13/11, Pancevo 26000,
decreased from pre-test values of 255 +/- 11 ms (mean +/- Yugoslavia.
SEM) to post-test values of 223 +/- 3 ms; average power in The purpose of this study was to examine the effects of acute
extension increased from 103 +/- 7 W pre-test to 112 +/- 7 W creatine-monohydrate supplementation on soccer-specific
post-test; and, during flexion, average power increased from performance in young soccer players. Twenty young male
59 +/- 5 W pre-test to 65 +/- 5 W post-test in the creatine soccer players (16.6 +/- 1.9 years) participated in the study
group as compared to controls (p .05). FFM, percent body fat, and were matched and allocated to 2 randomly assigned trials:
mid-quadriceps circumference, skinfold thickness of the ingesting creatine-monohydrate supplement (3 x 10-g doses)
Strength, Speed, Body Composition / Page 23
or placebo for 7 days. Before and after the supplementation Int J Sports Med. 2003 Feb;24(2):144-50.
protocol, each subject underwent a series of soccer-specific Effects of oral creatine-pyruvate supplementation in cycling
skill tests: dribble test, sprint-power test, endurance test, and performance.
vertical jump test. Specific dribble test times improved Van Schuylenbergh R, Van Leemputte M, Hespel P.
significantly in the creatine group (13.0 +/- 1.5 vs. 10.2 +/- 1.8 Exercise Physiology and Biomechanics Laboratory,
s; p < .05) after supplementation protocol. Sprint-power test Department of Kinesiology, Faculty of Physical Education
times were significantly improved after creatine-monohydrate and Physiotherapy, Katholieke Universiteit Leuven,
supplementation (2.7 +/- 0.4 vs. 2.2 +/- 0.5 s; p < .05) as well as Tervuursevest 101, B-3001 Leuven, Belgium.
vertical jump height (49.2 +/- 5.9 vs. 55.1 +/- 6.3 cm; p < .05) in A double-blind study was performed to evaluate the effects of
creatine trial. Furthermore, dribble and power test times, along oral creatine-pyruvate administration on exercise performance
with vertical jump height, were superior in creatine versus in well-trained cyclists. Endurance and intermittent sprint
placebo trial (p < .05) at post-supplementation performance. performance were evaluated before (pretest) and after
There were no changes in specific endurance test results (posttest) one week of creatine-pyruvate intake (Cr(pyr), 2 x
within or between trials (p > .05). There were no between-trial 3.5 g x d-1, n = 7) or placebo (PL, n = 7). Subjects firs t
differences in the placebo trial (p > .05). The main finding of performed a 1-hour time trial during which the workload could
the present study indicates that supplementation with be adjusted at 5-min intervals. Immediately they did five 10-
creatine in young soccer players improved soccer-specific sec sprints interspersed by 2-min rest intervals. Tests were
skill performance compared with ingestion of placebo. performed on an individual race bicycle that was mounted on
an ergometer. Steady-state power production on average was
Int J Sport Nutr Exerc Metab. 2003 Sep;13(3):294-302. about 235-245 W, which corresponded to blood lactate
Effect of alpha-lipoic acid combined with creatine concentrations of 4-5 mmol x l -1 and heart rate in the range of
monohydrate on human skeletal muscle creatine and 160-170 beats x min -1. Power outputs as well as blood lactate
phosphagen concentration. levels and heart rates were similar between Cr(pyr) and PL at
Burke DG, Chilibeck PD, Parise G, Tarnopolsky MA, Candow all times. Total work performed during the 1-h trial was 872 +/-
DG. 44 KJ in PL versus 891 +/- 51 KJ in CR pyr. During the
Department of Human Kinetics, St. Francis Xavier University, intermittent sprint test power peaked at about 800-1000 watt
Antigonish, Nova Scotia, Canada B2G 2W5. within 2-3 sec, decreasing by 15-20 % towards the end of each
Alpha-lipoic acid has been found to enhance glucose uptake sprint. Peak and mean power outputs were similar between
into skeletal muscle in animal models. Studies have also found groups at all times. Peak lactate concentrations after the final
that the co-ingestion of carbohydrate along with creatine sprint were approximately 11 mmol x l -1 in both groups during
increases muscle creatine uptake by a process related to both the pretest and the posttest. It is concluded that one
insulin-stimulated glucose disposal. The purpose of this week of creatine-pyruvate supplementation at a rate of 7 g x d
study was to determine the effect of alpha-lipoic acid on -1 does not beneficially impact on either endurance capacity
human skeletal muscle creatine uptake by directly measuring or intermittent sprint performance in cyclists.
intramuscular concentrations of creatine, phosphocreatine,
and adenosine triphosphate when creatine monohydrate was
co-ingested with alpha-lipoic acid. Muscle biopsies were Other Nutrients and Supplements
acquired from the vastus lateralis m. of 16 male subjects (18-32 Immunity and oxidative stress
y) before and after the experimental intervention. After the Nutrition. 2002 May;18(5):371-5.
initial biopsy, subjects ingested 20 g x d(-1) of creatine Can glutamine modify the apparent immunodepression
monohydrate, 20 g x d(-1) of creatine monohydrate + 100 g x observed after prolonged, exhaustive exercise?
d(-1) of sucrose, or 20 g x d(-1) of creatine monohydrate + 100 Castell LM.
g x d(-1) of sucrose + 1000 mg x d(-1) of alpha-lipoic acid for 5 University Department of Biochemistry, Oxford University,
days. Subjects refrained from exercise and consumed the same Oxford, United Kingdom. firstname.lastname@example.org
balanced diet for 7 days. Body weight increased by 2.1% Glutamine is an important fuel for some cells of the immune
following the nutritional intervention, with no differences system. In situations of stress, such as clinical trauma,
between the groups. There was a significant increase in total starvation, or prolonged, strenuous exercise, the
creatine concentration following creatine supplementation, concentration of glutamine in blood is decreased, often
with the group ingesting alpha-lipoic acid showing a substantially. In endurance athletes this decrease occurs
significantly greater increase (p < .05) in phosphocreatine concomitantly with relatively transient immunodepression.
(87.6 --> 106.2 mmol x kg(-1) dry mass [dm]) and total creatine Provision of glutamine or a glutamine precursor has been
(137.8 --> 156.8 mmol x kg(-1) dm). These findings indicate that found to decrease the incidence of illness in endurance
co-ingestion of alpha-lipoic acid with creatine and a small athletes. To date, it has not been established precisely which
amount of sucrose can enhance muscle total creatine content aspect of the immune system is affected by glutamine feeding
as compared to the ingestion of creatine and sucrose or during the transient immunodepression that occurs after
creatine alone. prolonged, strenuous exercise. However, there is increasing
evidence that neutrophils may be implicated.
/ Page 24
Nutrition. 1997 Jul-Aug;13(7-8):738-42. Int J Food Sci Nutr. 2004 Mar;55(2):131-41.
The effects of oral glutamine supplementation on athletes Whole blood and mononuclear cell glutathione response to
after prolonged, exhaustive exercise. dietary whey protein supplementation in sedentary and
Castell LM, Newsholme EA. trained male human subjects.
University Department of Biochemistry, Oxford, United Middleton N, Jelen P, Bell G.
Kingdom. Faculty of Agriculture, Food and Nutritional Sciences,
Athletes undergoing intense, prolonged training or University of Alberta, Edmonton, Alberta, Canada.
participating in endurance races suffer an increased risk of Sedentary male subjects (n=9) on a controlled diet were fed
infection due to apparent immunosuppression. Glutamine is two doses (0.8 or 1.6 g/kg body mass) of a whey protein
an important fuel for some cells of the immune system and isolate (WPI), in addition to an isocaloric placebo; blood
may have specific immunostimulatory effects. The plasma samples were drawn over a 4-h period and glutathione
glutamine concentration is lower after prolonged, exhaustive concentration determined. There was no effect of the
exercise: this may contribute to impairment of the immune supplementation at either level over the 4-h sampling period.
system at a time when the athlete may be exposed to The effects of a WPI supplemented diet on glutathione
opportunistic infections. The effects of feeding glutamine was concentrations in whole blood as well as peripheral
investigated both at rest in sedentary controls and after mononuclear cell populations were also investigated over a 6-
exhaustive exercise in middle-distance, marathon and ultra- week period in male subjects (n=18) involved in arduous
marathon runners, and elite rowers, in training and aerobic training; blood was collected prior to and following a
competition. Questionnaires established the incidence of 40 km simulated cycling trial. The aerobic training period
infection for 7 d after exercise: infection levels were highest in resulted in significantly lower glutathione concentrations in
marathon and ultra-marathon runners, and in elite male rowers whole blood, an effect that was mitigated by WPI
after intensive training. Plasma glutamine levels were supplementation. A significant increase in mononuclear cell
decreased by approximately 20% 1 h after marathon running. glutathione was also observed in subjects receiving the WPI
A marked increase in numbers of white blood cells occurred supplement following the 40 km simulated cycling trial.
immediately after exhaustive exercise, followed by a decrease
in the numbers of lymphocytes. The provision of oral Int J Sport Nutr Exerc Metab. 2004 Apr;14(2):125-32.
glutamine after exercise appeared to have a beneficial effect Moderate intensity resistance exercise, plus or minus soy
on the level of subsequent infections. In addition, the ratio of intake: effects on serum lipid peroxides in young adult males.
T-helper/T-suppressor cells appeared to be increased in Hill S, Box W, DiSilvestro RA.
samples from those who received glutamine, compared with Department of Human Nutrition at the Ohio State University,
placebo. Columbus, OH 4321-1295, USA.
Lipid peroxides can be both a product and an initiator of
Eur J Appl Physiol Occup Physiol. 1996;73(5):488-90. oxidant stress. Conceivably, exercise can either increase
Does glutamine have a role in reducing infections in athletes? concentrations of lipid peroxides (by causing oxidant stress),
Castell LM, Poortmans JR, Newsholme EA. or decrease them (by accelerating peroxide breakdown). The
University Department of Biochemistry, Oxford, UK. net effect could depend on exercise intensity and nutritional
There is an increased risk of infections in athletes undertaking intake of antioxidants. The present study examined the
prolonged, strenuous exercise. There is also some evidence response of serum lipid peroxides to the combination of
that cells of the immune system are less able to mount a moderate intensity, weight resistance exercise plus intake of
defence against infections after such exercise. The level of soy protein, a source of antioxidant phytochemicals.
plasma glutamine, an important fuel for cells of the immune Recreationally trained, young adult men (N = 18) consumed
system, is decreased in athletes after endurance exercise; this soy protein or antioxidant-poor whey protein for 4 weeks (40 g
may be partly responsible for the apparent protein/d) before a session of moderate intensity, weight
immunosuppression which occurs in these individuals. We resistance exercise. In the soy group, exercise decreased
monitored levels of infection in more than 200 runners and values for serum lipid peroxides at 5 min, 3 h, and 24 h post-
towers. The levels of infection were lowest in middle-distance exercise. The whey group showed the depression only at 24 h.
runners, and highest in runners after a full or ultramarathon In both the soy and whey groups, a small rise was seen for
and in elite rowers after intensive training. In the present interleukin-8, which is consistent with the idea that the
study, athletes participating in different types of exercise exercise session induced a moderate muscle stress. In
consumed two drinks, containing either glutamine (Group G) summary, a moderate intensity, weight resistance exercise
or placebo (Group P) immediately after and 2 h after exercise. session, despite inducing mild inflammation, depressed
They subsequently completed questionnaires (n = 151) about plasma serum peroxide values, especially when combined with
the incidence of infections during the 7 days following the 4 weeks of soy consumption.
exercise. The percentage of athletes reporting no infections
was considerably higher in Group G (81%, n = 72) than in Int J Sport Nutr Exerc Metab. 2003 Sep;13(3):369-81.
Group P (49%, n = 79, p < 0.001).
Other Nutrients and Supplements / Page 25
Antioxidant supplementation enhances neutrophil oxidative (GSH) concentration (p < 0.001), erythrocyte superoxide
burst in trained runners following prolonged exercise. dismutase (SOD) activity (p < 0.0001) and plasma total
Robson PJ, Bouic PJ, Myburgh KH. antioxidant status (TAS) (p < 0.05). Only in the supplemented
Department of Physiological Sciences, University of group (Su) with TT, did plasma glutathione peroxidase (GSH-
Stellenbosch, Private Bag X1, 7602 Matieland, South Africa. Px) activity decrease (p < 0.05) and CD4(+) cell concentration
paularobson@emailacc increase (p < 0.05). However, antioxidant supplementation
The influence of an antioxidant vitamin supplement on increased plasma TAS increase in response to exercise and
immune cell response to prolonged exercise was determined TT (p < 0.05). After exercise, TT also induced a lower decrease
using a randomized, double-blind, placebo-controlled, cross- in blood reduced and oxidized (GSSG) glutathione (p < 0.01) in
over study. Twelve healthy endurance subjects (n = 6 male, n both groups, but TT had no effect on lipoperoxidation as
= 6 female; mean +/- SD for age, 30.1 +/- 6.2 yr; height, 1.76 +/- estimated by plasma thiobarbituric reactive substances or on
7 m; body mass, 72.2 +/- 10.2 kg; VO2max, 63.7 +/- 12 ml x kg(- muscular damage occurrence estimated by plasma creatine
1) x min(-1)) participated in the study. Following a 3-week kinase isoenzyme MB mass. CONCLUSION: During TT,
period during which subjects ingested a multivitamin and - antioxidant supplementation at nutritional doses reinforces
mineral complex sufficient to meet the recommended daily antioxidant status response to exercise, with an effect on
allowance, they took either a placebo or an antioxidant vitamin exercise-induced oxidative stress, and no effect on oxidative
supplement (containing 18 mg beta-carotene, 900 mg vitamin damage.
C, and 90 mg vitamin E) for 7 days prior to a 2-h treadmill run
at 65% VO2max. Blood samples were drawn prior to and Int J Sport Nutr Exerc Metab. 2004 Apr;14(2):147-60.
immediately following exercise. These were analyzed for Antioxidant diet supplementation influences blood iron status
neutrophil oxidative burst activity, cortisol and glucose in endurance athletes.
concentrations, and white blood cell counts, as well as serum Aguilo A, Tauler P, Fuentespina E, Villa G, Cordova A, Tur
anti-oxidant vitamin concentrations. Plasma vitamin C, vitamin JA, Pons A.
E, and beta-carotene concentrations significantly increased Community Nutrition and Oxidative Stress Research Group at
following 7-day supplementation (p < .05). In comparison to the University of the Balearic Islands, Palma de Mallorca,
the placebo group, neutrophil oxidative burst was Spain.
significantly higher following exercise (p < .05), but no OBJECTIVE: The aim of this work was to check the effects of
differences were found in any other parameter following the 7- antioxidant supplementation (vitamins E and C, and beta-
day supplementation period. Although the impact of exercise carotene) on the basal iron status of athletes prior to and
on neutrophil function is multifactorial, our data suggest that following their training and competition season (3 months).
antioxidant supplementation may be of benefit to endurance DESIGN: Eighteen amateur trained male athletes were
athletes for the maintenance of this particular function of the randomly distributed in 2 groups: placebo (lactose) and
innate immune system following the 7-day supplementation antioxidant supplemented (vitamin E, 500 mg/d; vitamin C, 1
period. g/d; and beta -carotene, 30 mg/d). The study was double
blind. Hematological parameters, dietary intake, physical
J Am Coll Nutr. 2003 Apr;22(2):147-56. activity intensity, antioxidant status (GSH/GSSG ratio), and
Antioxidant supplementation and tapering exercise improve basal iron status (serum iron, transferrin, ferritin, and iron
exercise-induced antioxidant response. saturation index) were determined before and after the
Margaritis I, Palazzetti S, Rousseau AS, Richard MJ, Favier A. intervention trials. RESULTS: Exercise decreased antioxidant
Laboratoire de Physiologie Cellulaire et Moleculaire des defenses in the placebo group but not in the antioxidant-
Systemes Integres, CNRS UMR 6548, Faculte des Sciences du supplemented group. No changes were found in the number
Sport, Universite de Nice-Sophia-Antipolis, 261 Route de of erythrocytes, hematocrit, or hemoglobin concentration, or
Grenoble, BP 3259, 06205 Nice Cedex 3, France. in values of serum iron parameters, after taking the antioxidant
email@example.com cocktail for 3 months, in spite of the exercise completed. The
OBJECTIVE AND METHODS: The present controlled- placebo group showed a high oxidative stress index, and
training, double-blind study (supplemented, n = 7; placebo, n decreases in serum iron (24%) and iron saturation index (28%),
= 9) investigated whether taper training (TT) and antioxidant which can neither be attributed to aspects of the athletes'
supplementation, i.e., 150 micro g of selenium, 2000 IU of usual diet, nor to hemoconcentration. CONCLUSIONS:
retinol, 120 mg of ascorbic acid and 30 IU of alpha-tocopherol, Antioxidant supplementation prevents the decrease of serum
modulates antioxidant potential, redox status and oxidative iron and the iron saturation index, and a link between iron
damage occurrence both at rest and in response to exercise. metabolism and oxidative stress may also be suggested.
Two weeks of TT followed four weeks of overloaded training.
Dietary intakes were recorded. Before and after TT, triathletes J Strength Cond Res. 2003 Nov;17(4):801-9.
did a duathlon consisting of 5-km run, 20-km bike and 5-km Effects of vitamin E supplementation on recovery from
run. Biological studies were conducted at rest and after repeated bouts of resistance exercise.
exercise. RESULTS: Whatever the nutritional status, TT Avery NG, Kaiser JL, Sharman MJ, Scheett TP, Barnes DM,
induced a decrease in resting blood reduced glutathione Gomez AL, Kraemer WJ, Volek JS.
Other Nutrients and Supplements / Page 26
Human Performance Laboratory, Ball State University, induced oxidative stress, although differentially between the
Muncie, Indiana 47306, USA. young and older subjects, while age had no direct influence
The purpose of this study was to examine the effects of on these responses among this group of physically fit
vitamin E (VE) supplementation (1200 IU/day) on recovery subjects.
responses to repeated bouts of resistance exercise. Non-
resistance trained men were assigned to supplement with VE Biol Res Nurs. 2003 Jul;5(1):47-55.
(n = 9) or placebo (PL; n = 9) for 3 weeks and then perform 3 The effects of endurance exercise and vitamin E on oxidative
resistance exercise sessions separated by 3 days of recovery stress in the elderly.
(EX-1, EX-2, and EX-3). Performance was assessed at EX-1, Jessup JV, Horne C, Yarandi H, Quindry J.
EX-2, and EX-3. Fasting morning blood samples and University of Florida, College of Nursing, Box 100187,
perceived muscle soreness were obtained before EX-1 and for Gainesville, FL 32610-0187, USA. firstname.lastname@example.org
10 consecutive days. Muscle soreness peaked after EX-1 and To examine the effects of exercise and vitamin E
gradually returned to baseline values by day 6. Lower and supplementation on oxidative stress in older adults, 59
upper body maximal strength and explosive power were participants, age 76.3 +/- 4.2 years, were randomly assigned to
significantly (p < or = 0.05) decreased at EX-2 and EX-3 1 of 4 groups: an exercise group taking placebos (EGP) or
(approximately 10%). Plasma malondialdehyde (MDA) was vitamin E (EGE) or a sedentary group taking placebos (SGP) or
significantly elevated on days 7 and 8. There were no vitamin E (SGE). Measures included weight, VO2max, blood
significant differences between VE and PL in muscle soreness, pressure (BP), and serum concentrations of vitamin E and lipid
performance measures, or plasma MDA. Creatine kinase (CK) hydroperoxide (LOOH). At the end of the 16-week trial, the
area under the curve from day 1 to day 10 was significantly EGP and EGE had significant increases in VO2max and
greater for VE because of a nearly 2-fold greater increase in significant decreases in resting BP, weight, and LOOH
CK after EX-1 in VE, compared with PL (404 +/- 146 and 214 +/- concentrations (P < 0.05). The SGE had significant decreases
179 U/L, respectively). VE supplementation was not effective in LOOH and BP (P < 0.05). There were no significant changes
at attenuating putative markers of membrane damage, in the SGP (P > 0.05). The results suggest that endurance
oxidative stress, and performance decrements after repeated exercise in combination with vitamin E reduces oxidative
bouts of whole-body concentric/eccentric resistance exercise. stress, improves aerobic fitness, and reduces BP and weight
in older adults. Even sedentary participants who take vitamin
Free Radic Biol Med. 2003 Jun 15;34(12):1575-88. E may reduce oxidative stress and lower BP.
Effect of vitamin E and eccentric exercise on selected
biomarkers of oxidative stress in young and elderly men. Eur J Nutr. 2003 Aug;42(4):195-200.
Sacheck JM, Milbury PE, Cannon JG, Roubenoff R, Blumberg Vitamin E supplementation does not increase the vitamin C
JB. radical concentration at rest and after exhaustive exercise in
Nutrition, Exercise Physiology, and Sarcopenia Laboratory, healthy male subjects.
Tufts University, Boston, MA 02111, USA. Schneider M, Niess AM, Rozario F, Angres C, Tschositsch K,
Muscle damage resulting from eccentric exercise provides a Battenfeld N, Schaffer M, Northoff H, Dickhuth HH,
useful model of oxyradical-induced injury and can be used to Fehrenbach E, Trommer WE, Biesalski HK.
examine age-related responses to oxidative stress. Sixteen Dept. of Chemistry, University of Kaiserslautern, Postfach
young (26.4 +/- 3.3 years) and 16 older (71.1 +/- 4.0 years) 3049, 67653, Kaiserslautern, Germany.
healthy men were randomly assigned to 1000 IU/d vitamin E or BACKGROUND: Extensive exercise may promote the
placebo for 12 weeks and ran downhill for 45 min at 75% formation of reactive oxygen species and subsequently
VO(2)max, once before and following supplementation. Blood contribute to tissue damage. A compound which can protect
samples were obtained before (baseline) and immediately cells and tissues is vitamin E. The vitamin E radical, formed
postexercise (0 h), and at 6, 24, and 72 h postexercise to during the radical scavenging process, can be reduced by
determine antioxidant status, muscle damage, lipid vitamin C resulting in a higher level of the vitamin C radical
peroxidation, and DNA damage. Following exercise, young (semidehydroascorbate free radical). An increase of the
and older men experienced similar increases in serum creatine vitamin C radical, however, is assumed to exert prooxidative
kinase (CK), F(2alpha)-isoprostanes (iPF(2alpha); p <.001) and effects. AIM OF THE STUDY: To elucidate whether
malondialdehyde (MDA; p <.01), although iPF(2alpha) peaked supplementation of vitamin E and exhaustive exercise lead to
at 72 h postexercise and MDA peaked at 0 h. Oxygen Radical an increase of the vitamin C radical in human plasma.
Absorbance Capacity (ORAC) decreased at 72 h (p <.01) and METHODS: A placebo controlled, cross over study with 13
correlated with the rise in iPF(2alpha), MDA, and CK in the male volunteers was carried out. After an 8 day
young men (p <.05). Leukocyte 8-hydroxy-2'-deoxyguanosine supplementation period with 500 I.U. D-alpha-tocopherol, the
(8-OHdG) was unaffected by exercise. Vitamin E decreased subjects performed two exhaustive treadmill runs. Blood
peak CK in young men, while in older men it decreased resting samples were collected at rest, 0, 0.25, 1, 3, 24 and 48 h after
levels of iPF(2alpha) and suppressed the 24 h postexercise exercise. Serum was separated and concentrations of D-alpha-
increases in iPF(2alpha) (p <.05). Thus, vitamin E tocopherol and ascorbic acid were determined by HPLC.
supplementation induced modest changes eccentric exercise- Vitamin C radical levels in plasma were assessed by electron
Other Nutrients and Supplements / Page 27
paramagnetic resonance (EPR). RESULTS: Vitamin E and C provided an index of recovery. Blood lactate concentrations
both showed a tendency to decrease between 3 h and 24 h and pH measured prior to exercise and at the end of each
after exercise. Vitamin C radical level remained stable during workload were used to estimate blood buffer capacity (beta).
the whole period. Neither vitamin E supplementation nor Food intake was recorded daily for dietary analysis. There
exercise had any influence on the plasma concentration of the were no differences in macronutrient intakes (p >.56) or
vitamin C radical. CONCLUSIONS: Vitamin E supplementation training volumes (p >.99) between BC and WP during the
under conditions of mild oxidative stress does not result in an study period. Rowing performance (distance rowed and work
increased vitamin C radical concentration. done) during 4 max of ROW2 was less than ROW1 at baseline
(p <.05) but not different between groups (p >.05).
Colostrum Performance increased in both rows by Week 9 (p <.001), with
Int J Sport Nutr Exerc Metab. 2002 Dec;12(4):461-9. no difference between groups (p >.75). However, the increase
The effect of bovine colostrum supplementation on exercise was greatest in ROW2 (p <.05), such that by Week 9 there
performance in elite field hockey players. was no longer a difference in performance between the two
Hofman Z, Smeets R, Verlaan G, Lugt R, Verstappen PA. rows in either group (p >.05). b was not different between
Numico Research, Bosrandweg 20, 6704 PH Wageningen, The groups for ROW1 at baseline (BC 38.3 5.0, WP 38.2 7.2 slykes;
Netherlands. p >.05) but was higher in BC by Week 9 (BC 40.8 5.9, WP 33.4
In a double-blind, randomized, placebo-controlled study, we 5.3 slykes; p <.05). b for ROW2 followed the same pattern of
investigated the effect of 8 weeks of supplementation with change as for ROW1. We conclude that supplementation with
bovine colostrum (Intact) on body composition and exercise BC improves b, but not performance, in elite female rowers. It
performance (5 x 10-m sprint, vertical jump, shuttle-run test, was not possible to determine whether b had any effect on
and suicide test). Seventeen female and 18 male elite field recovery.
hockey players, including players from the Dutch national
team, received either 60 g of colostrum or whey protein daily. J Sports Sci. 2003 Jul;21(7):577-88.
The 5 x 10-m sprint test performance improved significantly (p Effect of bovine colostrum on anaerobic exercise performance
=.023) more in the colostrum group [0.64 +/- 0.09 s (mean +/- and plasma insulin-like growth factor I.
SEM)] compared to the whey group (0.33 +/- 0.09 s). The Buckley JD, Brinkworth GD, Abbott MJ.
vertical jump performance improved more in the colostrum School of Health Sciences, University of South Australia,
group (2.1 +/- 0.73 cm) compared to the whey group (0.32 +/- Holbrooks Road, Underdale, SA 5032, Australia.
0.82 cm). However, this was not statistically significant (p email@example.com
=.119). There were also no significant differences in changes In this study, we examined the effects of bovine colostrum on
in body composition and endurance tests between the 2 peak vertical jump power (VJpeak), peak cycle power
groups. It is concluded that in elite field hockey players, (CPpeak), alactic anaerobic work capacity, resistance exercise
colostrum supplementation improves sprint performance one-repetition maxima (1-RM) and plasma insulin-like growth
better than whey. However, there were no differences with factor I (IGF-I) concentrations. Using a randomized, double-
regard to body composition or endurance performance. blind, placebo-controlled, parallel design, 51 males completed
8 weeks of resistance and plyometric training while
Int J Sport Nutr Exerc Metab. 2002 Sep;12(3):349-65. consuming 60 g x day(-1) of bovine colostrum (n = 26) or
Oral bovine colostrum supplementation enhances buffer concentrated whey protein powder (n = 25). Peak vertical jump
capacity but not rowing performance in elite female rowers. power, peak cycle power, alactic anaerobic work capacity, 1-
Brinkworth GD, Buckley JD, Bourdon PC, Gulbin JP, David A. RM and plasma IGF-I were not different between groups at
Centre for Research in Education and Sports Science at the baseline (P > 0.33). Peak vertical jump power and peak cycle
University of South Australia, Adelaide 5032, South Australia. power were still not significantly different between groups by
A randomized, double-blind, placebo controlled design was week 4 (VJpeak: bovine colostrum, 7231 +/- 488 W; whey
used in which 13 elite female rowers, all of whom had protein, 7214 +/- 530 W; P = 0.99; CPpeak: bovine colostrum,
competed at World Championships, were supplemented with 1272 +/- 202 W; whey protein, 1232 +/- 208 W; P = 0.99). By
60 g day-1 of either bovine colostrum (BC; n = 6) or week 8, however, peak vertical jump power (bovine colostrum,
concentrated whey protein powder (WP; n = 7) during 9 7370 +/- 503 W; whey powder, 7237 +/- 481 W; 95%
weeks of pre-competition training. All subjects undertook the confidence intervals, 54 to 170 W; P < 0.01) and peak cycle
study as a group and completed the same training program. power (bovine colostrum, 1400 +/- 215 W; whey protein, 1311
Prior to, and after 9 weeks of supplementation and training, +/- 192 W; 95% confidence intervals, 20 to 61 W; P < 0.01)
subjects completed an incremental rowing test (ROW1) on a were significantly higher in the bovine colostrum condition.
rowing ergometer consisting of 3 3 4-min submaximal Alactic anaerobic work capacity and 1-RM increased (P <
workloads and a 4-min maximal effort (4 max), each separated 0.001), but the increases were not different between groups (P
by a 1-min recovery period. The rowing test was repeated > 0.08). Plasma IGF-I did not change in either group (P = 0.55).
after a 15-min period of passive recovery (ROW2). The 4 max We conclude that bovine colostrum supplementation during
for ROW1 provided a measure of performance, and the training significantly increased peak anaerobic power, but had
difference between the 4 max efforts of ROW1 and ROW2
Other Nutrients and Supplements / Page 28
no effect on alactic anaerobic work capacity, 1-RM or plasma threshold was estimated), a time to fatigue test at 110% of
IGF-I. ventilatory threshold, and a 40 km time trial (TT40). Cyclists
were then assigned to either a supplement (n = 14, 10 g/day
J Appl Physiol. 2007 Mar;102(3):1113-22. bovine colostrum protein concentrate (CPC)) or a placebo
Effects of bovine colostrum supplementation on immune group (n = 15, 10 g/day whey protein) and resumed their
variables in highly trained cyclists. normal training. Following 5 weeks of supplementation, the
Shing CM, Peake J, Suzuki K, Okutsu M, Pereira R, Stevenson cyclists returned to the laboratory to complete a second series
L, Jenkins DG, Coombes JS. of performance testing (week 7). They then underwent five
School of Human Movement Studies, The University of consecutive days of HIT (week 8) followed by a further series
Queensland, St. Lucia, Queensland, Australia 4072. of performance tests (week 9). RESULTS: The influence of
firstname.lastname@example.org bovine CPC on TT40 performance during normal training was
The aim of this study was to investigate the influence of low- unclear (week 7: 1+/-3.1%, week 9: 0.1+/-2.1%; mean+/-90%
dose bovine colostrum protein concentrate (CPC) confidence limits). However, at the end of the HIT period,
supplementation on selected immune variables in cyclists. bovine CPC supplementation, compared to the placebo,
Twenty-nine highly trained male road cyclists completed an elicited a 1.9+/-2.2% improvement from baseline in TT40
initial 40-km time trial (TT(40)) and were then randomly performance and a 2.3+/-6.0% increase in time trial intensity
assigned to either a supplement (n = 14, 10 g bovine CPC/day) (% VO(2max)), and maintained TT40 heart rate (2.5+/-3.7%). In
or placebo group (n = 15, 10 g whey protein concentrate/day). addition, bovine CPC supplementation prevented a decrease
After 5 wk of supplementation, the cyclists completed a in ventilatory threshold following the HIT period (4.6+/-4.6%).
second TT(40). They then completed 5 consecutive days of CONCLUSION: Low dose bovine CPC supplementation
high-intensity training (HIT) that included a TT(40), followed elicited improvements in TT40 performance during an HIT
by a final TT(40) in the following week. Venous blood and period and maintained ventilatory threshold following five
saliva samples were collected immediately before and after consecutive days of HIT.
each TT(40), and upper respiratory illness symptoms were
recorded over the experimental period. Compared with the Amino Acids. 2005 May;28(3):327-35.
placebo group, bovine CPC supplementation significantly Protein metabolism and strength performance after bovine
increased preexercise serum soluble TNF receptor 1 during the colostrum supplementation.
HIT period (bovine CPC = 882 +/- 233 pg/ml, placebo = 468 +/- Mero A, Nykanen T, Keinanen O, Knuutinen J, Lahti K, Alen
139 pg/ml; P = 0.039). Supplementation also suppressed the M, Rasi S, Leppaluoto J.
postexercise decrease in cytotoxic/suppressor T cells during Department of Biology of Physical Activity, University of
the HIT period (bovine CPC = -1.0 +/- 2.7%, placebo = -9.2 +/- Jyvaskyla, Jyvaskyla, Finland. email@example.com
2.8%; P = 0.017) and during the following week (bovine CPC = This study was designed to determine the responses of
1.4 +/- 2.9%, placebo = -8.2 +/- 2.8%; P = 0.004). Bovine CPC muscle protein, serum amino acids, and strength performance
supplementation prevented a postexercise decrease in serum to bovine colostrum supplementation in physically active
IgG(2) concentration at the end of the HIT period (bovine CPC men. The rest (R) group (n = 6) and the exercise (E) group (n =
= 4.8 +/- 6.8%, P = 0.88; placebo = -9.7 +/- 6.9%, P = 0.013). 6) carried out twice a 2-week experiment randomly assigned in
There was a trend toward reduced incidence of upper a double-blind fashion with either placebo (PLA; consuming
respiratory illness symptoms in the bovine CPC group (P = daily 20 g maltodextrin) or bovine colostrum (COL; consuming
0.055). In summary, low-dose bovine CPC supplementation daily 20 g colostrum supplement) treatment with one month
modulates immune parameters during normal training and after between. On the test day after the treatment period the
an acute period of intense exercise, which may have measurements were carried out in fasting conditions and E
contributed to the trend toward reduced upper respiratory carried out a strength training session (STS). The methods
illness in the bovine CPC group. involved the infusion of ring-(2)H(5)-phenylalanine, femoral
arterial and venous blood sampling, and biopsies from the
Br J Sports Med. 2006 Sep;40(9):797-801. vastus lateralis muscle. Serum concentration of essential
The influence of bovine colostrum supplementation on amino acids during recovery was greater (p < 0.05) in the COL
exercise performance in highly trained cyclists . groups compared with the PLA groups. Both muscle protein
Shing CM, Jenkins DG, Stevenson L, Coombes JS. synthesis and breakdown increased (p < 0.05) with COL.
School of Human Movement Studies, The University of There were no differences in phenylalanine net balance or
Queensland, St. Lucia, Brisbane, Qld 4072, Australia. strength performance between the PLA and COL groups. It
firstname.lastname@example.org was concluded that a 2-week supplementation with bovine
PURPOSE: The aim of this experiment was to investigate the colostrum in physically active men increases serum
influence of low dose bovine colostrum supplementation on concentration of essential amino acids but has no effect either
exercise performance in cyclists over a 10 week period that on strength performance or protein net balance in fasting
included 5 days of high intensity training (HIT). METHODS: conditions during recovery after STS.
Over 7 days of preliminary testing, 29 highly trained male road
cyclists completed a VO(2max) test (in which their ventilatory Eur J Appl Physiol. 2004 Jan;91(1):53-60.
Other Nutrients and Supplements / Page 29
Effect of bovine colostrum supplementation on the 3 kg, P=0 x 046) with BMI >30 kg/m2 (Delta=-1 x 9 kg, P=0 x
composition of resistance trained and untrained limbs in 011), compared with placebo. The waist-hip ratio decreased
healthy young men. significantly (P=0 x 043) compared with placebo. LBM
Brinkworth GD, Buckley JD, Slavotinek JP, Kurmis AP. increased (Delta=+0 x 5 kg, P=0 x 049) within the CLA group.
Centre for Research in Education and Sports Science, School Bone mineral content was not affected (P=0 x 70). All changes
of Physical Education, Exercise and Sport Studies, University were independent of diet and physical exercise. Safety
of South Australia, Holbrooks Road, 5032 Underdale, South parameters including blood lipids, inflammatory and
Australia, Australia. diabetogenic markers remained within the normal range.
This study examined the effect of bovine colostrum (BC) Adverse events did not differ between the groups. It is
supplementation on the tissue composition of resistance concluded that supplementation with CLA in healthy,
trained (T) and untrained (UT) limbs. Using a double-blind overweight and obese adults decreases BFM in specific
design, subjects were randomly allocated to 60 g day(-1) of regions and is well tolerated.
BC ( n=17) or whey protein (WP) ( n=17) during 8 weeks of
resistance training of the elbow flexors (EF) of their non- J Sports Med Phys Fitness. 2006 Dec;46(4):570-7.
dominant arm (T). Axial magnetic resonance images of both Cumulative effects of conjugated linoleic acid and exercise on
upper arms, maximal voluntary isometric torque (MVC) of EF, endurance development, body composition, serum leptin and
and the one repetition maximum (1RM) for bicep curls were insulin levels.
measured pre- and post-supplementation. There were no Colakoglu S, Colakoglu M, Taneli F, Cetinoz F, Turkmen M.
differences in macronutrient intakes ( P>0.28) or the volume of School of Physical Education and Sports, Celal Bayar
training completed by T ( P=0.98) between the two groups. T University, Manisa, Turkey. email@example.com,tr
of BC experienced a significantly greater increase in AIM: The aim of this study was to evaluate the accruing
circumference [BC 2.3 (3.0)%, WP 0.0 (4.2)%; P=0.05] and effects of conjugated linoleic acid (CLA) supplementation and
cross-sectional area (CSA) [BC 4.2 (6.0)%, WP -0.2 (8.3)%; aerobic exercise (Ex) on body composition and serum lipid
P=0.05] compared with WP, due principally to a greater profile in humans. METHODS: Forty-four healthy female
increase in skin and subcutaneous fat (SSF) CSA [BC 5.5 young subjects were divided ExCLA, CLA, Ex and control (C)
(10.9)%, WP -2.7 (14.1)%; P=0.03]. No tissue compartment groups. The groups of CLA and ExCLA were supplemented
changed significantly in UT of either group ( P>0.05). MVC with 3.6 g/d CLA whilst ExCLA and Ex groups were exercised
and 1RM increased for T and UT in both groups ( P<0.05), but for 30 min(-1.)3 days(-1.)week(-1) for 6 weeks. RESULTS: After
the increases were not different between groups ( P>0.32). the study period, fat ratio, fat mass, waist and hip girths were
Since the SSF compartment increased in T but not UT, and fat reduced in all experimental groups and fat-free mass induced
turnover in adipocytes is under hormonal control and would in ExCLA and CLA groups and body weight was reduced in
not be localised to one arm, we suggest that the increase in the CLA group when compared to baseline levels. These
SSF CSA in T of BC may have been due to an increase in skin alterations were significantly different than those of controls
CSA, rather than fat. with the highest variations were observed in the ExCLA.
There was no change in serum leptin, apo-AI, apo-B, total
Conjugated linoleic acid (CLA) cholesterol, HDL, LDL, free fatty acid, and triglyceride levels.
Br J Nutr. 2007 Mar;97(3):550-60. Serum glucose concentrations of ExCLA and CLA groups and
Six months supplementation with conjugated linoleic acid insulin level of ExCLA group decreased significantly as
induces regional-specific fat mass decreases in overweight compared to baseline levels with only serum glucose
and obese. reduction of both groups were significantly different than
Gaullier JM, Halse J, Hoivik HO, Hoye K, Syvertsen C, those of controls (P<0.05). Endurance performance
Nurminiemi M, Hassfeld C, Einerhand A, O'Shea M, significantly increased in ExCLA and Ex groups (P<0.01) but
Gudmundsen O. did not vary in the CLA and controls. CONCLUSIONS: It was
Link Medical Research AS, Kjeller, Norway. firstname.lastname@example.org shown that both CLA and exercise were effective in
Long-term supplementation with conjugated linoleic acid improvement of body composition and these effects were
(CLA) reduces body fat mass (BFM) and increases or cumulated when they have been used together. CLA
maintains lean body mass (LBM). However, the regional effect supplementation alone or with exercise seems effective on
of CLA was not studied. The study aimed to evaluate the serum glucose and insulin concentrations but ineffective on
effect of CLA per region and safety in healthy, overweight endurance performance.
and obese adults. A total of 118 subjects (BMI: 28-32 kg/m2)
were included in a double blind, placebo-controlled trial. Int J Obes (Lond). 2006 Oct 10;
Subjects were randomised into two groups supplemented with The effect of 6 months supplementation with conjugated
either 3 x 4 g/d CLA or placebo for 6 months. CLA linoleic acid on insulin resistance in overweight and obese.
significantly decreased BFM at month 3 (Delta=- 0 x 9 %, P=0 Syvertsen C, Halse J, Hoivik HO, Gaullier JM, Nurminiemi M,
x 016) and at month 6 (Delta=- 3 x 4 %, P=0 x 043) compared Kristiansen K, Einerhand A, O'shea M, Gudmundsen O.
with placebo. The reduction in fat mass was located mostly in Scandinavian Clinical Research AS, Kjeller, Norway.
the legs (Delta=- 0 x 8 kg, P<0 x 001), and in women (Delta=-1 x
Other Nutrients and Supplements / Page 30
Background: Contradicting results have been published in an open study for another 12 mo. The goals of the
regarding the effect of conjugated linoleic acid (CLA) on extension study were to evaluate the safety [with clinical
insulin resistance. However, only a few studies have used the chemistry analyses and reported adverse events (AEs)] and
euglycemic hyperinsulinemic clamp method, which is assess the effects of CLA on body composition [body fat
considered the standard for measuring insulin resistance. mass (BFM), lean body mass (LBM), bone mineral mass
Objective: To evaluate if CLA as a mixture of the main isomers (BMM)], body weight, and BMI. All subjects were
trans-10 cis-12 and cis-9 trans-11 affects the insulin resistance supplemented with 3.4g CLA/d in the triglyceride form.
in healthy overweight and obese male and female adults. Circulating lipoprotein(a) and thrombocytes increased in all
Design: The main study was a randomized, double-blind, groups. There was no change in fasting blood glucose.
placebo-controlled trial with change in body composition as Aspartate amino transferase, but not alanine amino
primary end point comprising 118 subjects receiving transferase, increased significantly. Plasma total cholesterol
supplementation with either placebo (olive oil) or CLA and LDL cholesterol were reduced, whereas HDL cholesterol
(Clarinol) for 6 months. A sub-population of 49 subjects and triglycerides were unchanged. The AE rate decreas ed
agreed additionally to participate in an euglycemic compared with the first 12 mo of the study. Body weight and
hyperinsulinemic clamp study at baseline and after 6 months BFM were reduced in the subjects administered the placebo
of supplementation with study drug. The primary outcome during the initial 12 mo study (-1.6 +/- 3.2 and -1.7 +/- 2.8 kg,
was the change in glucose uptake (M) as measured by the respectively). No fat or body weight changes occurred in the
hyperinsulinemic euglycemic glucose clamp method. 2 groups given CLA during the initial 12 mo. LBM and BMM
Secondary outcomes were the correlates between insulin were not affected in any of the groups. Changes in body
resistance and changes in body composition or blood composition were not related to diet and/or training. In
chemistry parameters. Forty-one subjects completed the conclusion, this study shows that CLA supplementation for
clamp test at both time points. Results: The median M of the 24 mo in healthy, overweight adults was well tolerated. It
CLA group was 11.0 mg min(-1) lean body mass (lbm)(-1) confirms also that CLA decreases BFM in overweight
(n=24) at baseline, 10.3 mg min(-1) lbm(-1) (n=24) after 6 humans, and may help maintain initial reductions in BFM and
months, and the median difference was +0.21 mg min(-1) lbm(- weight in the long term.
1) (n=24). The median M of placebo group was 8.4 mg min(-1)
lbm(-1) at baseline and 9.3 mg min(-1) lbm(-1) after 6 months Am J Clin Nutr. 2004 Jun;79(6):1118-25.
and the median difference was -0.22 mg min(-1) lbm(-1) (n=17). Conjugated linoleic acid supplementation for 1 y reduces
No significant (P<0.05) differences were found within groups body fat mass in healthy overweight humans.
or between groups. Likewise, the glucose uptake insulin Gaullier JM, Halse J, Hoye K, Kristiansen K, Fagertun H, Vik
concentration ratio during clamp (M/I) was independent of H, Gudmundsen O.
treatment and time. Homeostasis model assessment (HOMA) Scandinavian Clinical Research AS, Kjeller, Norway. j-
and quantitative insulin sensitivity check index derived from email@example.com
fasting glucose and insulin were also independent of BACKGROUND: Short-term trials showed that conjugated
treatment and time, and HOMA for the clamp population linoleic acid (CLA) may reduce body fat mass (BFM) and
(n=49) corresponded well with HOMA for the per protocol increase lean body mass (LBM), but the long-term effect of
population (n=83). Correlation analysis showed that changes CLA was not examined. OBJECTIVE: The objective of the
in M were inversely correlated to changes in study was to ascertain the 1-y effect of CLA on body
glucohemoglobin (P=0.002), but did not correlate with composition and safety in healthy overweight adults
changes in either glucose, insulin, insulin c-peptide, leptin, consuming an ad libitum diet. DESIGN: Male and female
adiponectin or percent body fat. Conclusions: CLA does not volunteers (n = 180) with body mass indexes (in kg/m(2)) of
affect glucose metabolism or insulin sensitivity in a 25-30 were included in a double-blind, placebo-controlled
population of overweight or obese volunteers. study. Subjects were randomly assigned to 3 groups: CLA -
free fatty acid (FFA), CLA-triacylglycerol, or placebo (olive
J Nutr. 2005 Apr;135(4):778-84. oil). Change in BFM, as measured by dual-energy X-ray
Supplementation with conjugated linoleic acid for 24 months absorptiometry, was the primary outcome. Secondary
is well tolerated by and reduces body fat mass in healthy, outcomes included the effects of CLA on LBM, adverse
overweight humans. events, and safety variables. RESULTS: Mean (+/- SD) BFM
Gaullier JM, Halse J, Hoye K, Kristiansen K, Fagertun H, Vik in the CLA-triacylglycerol and CLA-FFA groups was 8.7 +/-
H, Gudmundsen O. 9.1% and 6.9 +/- 9.1%, respectively, lower than that in the
Scandinavian Clinical Research AS, NO-2027 Kjeller, placebo group (P < 0.001). Subjects receiving CLA-FFA had
Norway. firstname.lastname@example.org 1.8 +/- 4.3% greater LBM than did subjects receiving placebo
After 12 mo in a randomized, double-blind, placebo-controlled (P = 0.002). These changes were not associated with diet or
trial of conjugated linoleic acid (CLA) supplementation (2 exercise. LDL increased in the CLA-FFA group (P = 0.008),
groups received CLA as part of a triglyceride or as the free HDL decreased in the CLA-triacylglycerol group (P =
fatty acid, and 1 group received olive oil as placebo), 134 of 0.003), and lipoprotein(a) increased in both CLA groups (P
the 157 participants who concluded the study were included < 0.001) compared with month 0. Fasting blood glucose
Other Nutrients and Supplements / Page 31
concentrations remained unchanged in all 3 groups. Glycated Departament de Bioquimica i Biotecnologia, Facultat de
hemoglobin rose in all groups from month 0 concentrations, Medicina i Ciencies de la Salut de Reus, Spain.
but there was no significant difference between groups. email@example.com
Adverse events did not differ significantly between groups. Studies performed on different species show that the
CONCLUSION: Long-term supplementation with CLA-FFA or consumption of conjugated linoleic acid (CLA) leads to a loss
CLA-triacylglycerol reduces BFM in healthy overweight of fat and total body weight, reduces the plasma
adults. concentrations of total and LDL cholesterol, and has an
antiinflammatory effect. This article reviews the clinical trials
J Strength Cond Res. 2002 Aug;16(3):325-34. on human beings that evaluate how mixtures of CLA isomers
Effects of conjugated linoleic acid supplementation during administered as supplements or CLA-enriched products can
resistance training on body composition, bone density , affect total body weight, body composition, plasma lipid
strength, and selected hematological markers. profile, glycemia, insulinemia, insulin sensitivity, lipid
Kreider RB, Ferreira MP, Greenwood M, Wilson M, Almada oxidation, and inflammation. After analyzing the few studies
AL. published to date in reduced samples of healthy humans or
Exercise and Sport Nutrition Laboratory, Department of patients with overweight, obesity, metabolic syndrome, or
Human Movement Sciences and Education, University of diabetes, we deduce that there is not enough evidence to
Memphis, Tennessee 38152, USA. show that conjugated linoleic acid has an effect on weight
firstname.lastname@example.org and body composition in humans. However, some of these
Conjugated linoleic acids (CLA) are essential fatty acids that studies have observed that the administration of various CLA
have been reported in animal studies to decrease catabolism, isomers has adverse effects on lipid profile (it decreases HDL
promote fat loss, increase bone density, enhance immunity, cholesterol concentration and increases Lp(a) circulating
and serve as an antiatherogenic and anticarcinogenic agent. levels), glucose metabolism (glycemia, insulinemia or insulin
For this reason, CLA has been marketed as a supplement to sensitivity), lipid oxidation, inflammation, or endothelial
promote weight loss and general health. CLA has also been function. Therefore, long-term randomized clinical trials,
heavily marketed to resistance-trained athletes as a controlled with placebo, need to be made in large samples of
supplement that may help lessen catabolism, decrease body patients to evaluate the efficacy and safety of CLA isomers
fat, and promote greater gains in strength and muscle mass before its indiscriminate use in human beings can be
during training. Although basic research is promising, few recommended.
studies have examined whether CLA supplementation during
training enhances training adaptations and/or affects markers Tidsskr Nor Laegeforen. 2004 Dec 2;124(23):3051-4.
of health. This study evaluated whether CLA [Can linoleic acids in conjugated CLA products reduce
supplementation during resistance training affects body overweight problems?]
composition, strength, and/or general markers of catabolism Haugen M, Alexander J.
and immunity. In a double-blind and randomized manner, 23 Avdeling for naeringsmiddeltoksikologi, Divisjon for
experienced, resistance-trained subjects were matched miljomedisin, Nasjonalt folkehelseinstitutt, Postboks 4404
according to body mass and training volume and randomly Nydalen, 0403 Oslo. email@example.com
assigned to supplement their diet with 9 g;pdd(-1) of an olive BACKGROUND: CLA (conjugated linoleic acid) supplements
oil placebo or 6 g;pdd(-1) of CLA with 3 g;pdd(-1) of fatty are advertised as a way to reduce weight and to obtain a
acids for 28 days. Prior to and following supplementation, "better balance between fat and muscle". What evidence is
fasting blood samples, total body mass, and dual-energy X- there for these health claims, and is CLA supplementation
ray absorptiometry (DEXA) determined body composition, safe and without adverse effects? MATERIAL AND
and isotonic bench press and leg press 1 repetition maximums METHODS: This review is based on peer-reviewed scientific
(1RMs) were determined. Results revealed that although some publications. RESULTS: Large doses of CLA s upplements in
statistical trends were observed with moderate to large effect rodents reduce fat mass and increases muscle mass, but the
sizes, CLA supplementation did not significantly affect (p > results from 13 randomised, placebo-controlled clinical studies
0.05) changes in total body mass, fat-free mass, fat mass, do not support these findings with regard to humans.
percent body fat, bone mass, strength, serum substrates, or However, results from both animal and human studies indicate
general markers of catabolism and immunity during training. that the CLA isomer 10-trans,12-cis may have a negative
These findings indicate that CLA does not appear to possess impact on carbohydrate and lipid metabolism by inducing
significant ergogenic value for experienced resistance-trained insulin resistance and hyperlipidaemia. Studies of CLA
athletes. supplementation to lactating women have revealed lower fat
content in their milk. Furthermore, the cordial blood
Crit Rev Food Sci Nutr. 2006;46(6):479-88. concentration of CLA in women has been shown to correlate
Conjugated linoleic acid intake in humans: a systematic review negatively with both gestational length and birth weight.
focusing on its effect on body composition, glucose, and lipid CONCLUSION: Even if reduced weight and fat mass has been
metabolism. observed in animal models following CLA supplementation,
Salas-Salvado J, Marquez-Sandoval F, Bullo M. the basis is, at best, weak for such claims in humans. Provided
Other Nutrients and Supplements / Page 32
that the fat mass reducing effect of CLA is mediated through Dietary supplements containing conjugated linoleic acid
PPARgamma, this may result in adverse metabolic effects. (CLA) are widely promoted as weight loss agents available
over the counter and via the Internet. In this review, we
Int J Obes Relat Metab Disord. 2004 Aug;28(8):941-55. evaluate the efficacy and safety of CLA supplementation
Conjugated linoleic acid and obesity control: efficacy and based on peer-reviewed published results from randomized,
mechanisms. placebo-controlled, human intervention trials lasting more
Wang YW, Jones PJ. than 4 weeks. We also review findings from experimental
School of Dietetics and Human Nutrition, Macdonald studies in animals and studies performed in vitro. CLA
Campus, McGill University, Ste-Anne-de-Bellevue, Quebec, appears to produce loss of fat mass and increase of lean
Canada. tissue mass in rodents, but the results from 13 randomized,
Obesity is associated with high blood cholesterol and high controlled, short-term (<6 months) trials in humans find little
risk for developing diabetes and cardiovascular disease. evidence to support that CLA reduces body weight or
Therefore, management of body weight and obesity are promotes repartitioning of body fat and fat-free mass in man.
increasingly considered as an important approach to However, there is increasing evidence from mice and human
maintaining healthy cholesterol profiles and reducing studies that the CLA isomer trans -10, cis-12 may produce liver
cardiovascular risk. The present review addresses the effects hypertrophy and insulin resistance via a redistribution of fat
of conjugated linoleic acid (CLA) on fat deposition, body deposition that resembles lipodystrophy. CLA also decreases
weight and composition, safety, as well as mechanisms the fat content of both human and bovine milk. In conclusion,
involved in animals and humans. Animal studies have shown although CLA appears to attenuate increases in body weight
promising effects of CLA on body weight and fat deposition. and body fat in several animal models, CLA isomers sold as
The majority of the animal studies have been conducted using dietary supplements are not effective as weight loss agents in
CLA mixtures that contained approximately equal amounts of humans and may actually have adverse effects on human
trans-10, cis-12 (t10c12) and cis-9, trans-11 (c9t11) isomers. health.
Results of a few studies in mice fed CLA mixtures with
different ratios of c9t11 and t10c12 isomers have indicated HMB
that the t10c12 isomer CLA may be the active form of CLA J Appl Physiol. 2003 Feb;94(2):651-9. Epub 2002 Oct 25.
affecting weight gain and fat deposition. Inductions of leptin Effect of dietary supplements on lean mass and strength gains
reduction and insulin resistance are the adverse effects of with resistance exercise: a meta-analysis.
CLA observed in only mice. In pigs, the effects of CLA on Nissen SL, Sharp RL.
weight gain and fat deposition are inconsistent, and no Department of Animal Science, Iowa State University, Ames
adverse effects of CLA have been reported. A number of 50011, USA. firstname.lastname@example.org
human studies suggest that CLA supplementation has no The purpose of this study was to quantify which dietary
effect on body weight and insulin sensitivity. Although it is supplements augment lean mass and strength gains during
suggested that the t10c12 CLA is the antiadipogenic isomer of resistance training. Peer-reviewed studies between the years
CLA in humans, the effects of CLA on fat deposition are 1967 and 2001 were included in the analysis if they met a
marginal and more equivocal as compared to results observed predetermined set of experimental criteria, among which were
in animal studies. Mechanisms through which CLA reduces at least 3-wk duration and resistance-training 2 or more times a
body weight and fat deposition remain to be fully understood. week. Lean mass and strength were normalized for meta-
Proposed antiobesity mechanisms of CLA include decreased analysis by conversion to percent change per week and by
energy/food intake and increased energy expenditure, calculating the effect size for each variable. Of the 250
decreased preadipocyte differentiation and proliferation, supplements examined, only 6 had more than 2 studies that
decreased lipogenesis, and increased lipolysis and fat met the criteria for inclusion in the meta-analysis. Creatine and
oxidation. In summary, CLA reduces weight gain and fat beta-hydroxy-beta-methylbutyrate (HMB) were found to
deposition in rodents, while produces less significant and significantly increase net lean mass gains of 0.36 and
inconsistent effects on body weight and composition in pigs 0.28%/wk and strength gains of 1.09 and 1.40%/wk (P < 0.05),
and humans. New studies are required to examine isomer- respectively. Chromium, dehydroepiandrosterone,
specific effects and mechanisms of CLA in animals and androstenedione, and protein did not significantly affect lean
humans using purified individual CLA isomers. gain or strength. In conclusion, two supplements, creatine
and HMB, have data supporting their use to augment lean
J Lipid Res. 2003 Dec;44(12):2234-41. mass and strength gains with resistance training.
Efficacy and safety of dietary supplements containing CLA
for the treatment of obesity: evidence from animal and human J Strength Cond Res. 2003 Feb;17(1):34-9.
studies. The effect of beta-hydroxy beta-methylbutyrate on muscular
Larsen TM, Toubro S, Astrup A. strength and body composition in collegiate football players.
Department of Human Nutrition, Center for Advanced Food Ransone J, Neighbors K, Lefavi R, Chromiak J.
Studies, The Royal Veterinary and Agricultural University, College of Education, Oklahoma State University, Stillwater,
DK-1958 Frederiksberg C, Denmark. email@example.com Oklahoma 74078, USA. firstname.lastname@example.org
Other Nutrients and Supplements / Page 33
This study assesses the effects of daily beta-hydroxy beta- rosea extract containing 3% rosavin + 1% salidroside plus 500
methylbutyrate (HMB) supplementation on muscular strength mg starch) or placebo (P, 700 mg starch) speed of limb
(bench press, squats, and power cleans) and body movement (plate tapping test), aural and visual reaction time,
composition (body weight and body fat) among collegiate and the ability to sustain attention (Fepsy Vigilance test) were
football players undergoing a strenuous exercise program. assessed. Day 2: Following the same intake procedure as on
Subjects were collegiate football players (n = 35) training day 1, maximal isometric knee-extension torque and endurance
under the supervision of certified strength coaches averaging exercise capacity were tested. Following a 5-day washout
20 hours of weekly exercise. In the first supplementation period, the experimental procedure was repeated, with the
period, 16 of the 35 subjects were supplemented with 3 g of treatment regimens being switched between groups (session
HMB per day for 4 weeks; the other 19 received a placebo 2). PHASE II: A double blind placebo-controlled study (n =
followed by a 1-week washout period and then a second 12) was performed. Subjects underwent sessions 3 and 4,
supplementation period in a randomized double-blind identical to Phase I, separated by a 4-week R/P intake, during
crossover, placebo design. There were no significant changes which subjects ingested 200 mg R/P per day. RESULTS:
(p > 0.05) in muscular strength, including bench press, squats, PHASE I: Compared with P, acute R intake in Phase I
and power cleans, among the subjects. There were also no increased (p <.05) time to exhaustion from 16.8 +/- 0.7 min to
significant changes (p > 0.05) in body composition, including 17.2+/- 0.8 min. Accordingly, VO2peak (p <.05) and VCO2peak
body fat and body weight. Very little clinical evidence exists (p<.05) increased during R compared to P from 50.9 +/- 1.8 ml x
for supplementing HMB in athletic populations. min(-1) x kg(- )1 to 52.9 +/- 2.7 ml x min(-10) x kg(-1) (VO2peak)
and from 60.0 +/- 2.3 ml x min(-1) x kg(-1) to 63.5+/- 2.7 ml x
Rhodiola min(-1) x kg(-1) (VCO2peak). Pulmonary ventilation (p =.07)
Int J Sport Nutr Exerc Metab. 2006 Jun;16(3):305-15. tended to increase more during R than during P (P: 115.9+/- 7.7
Does Rhodiola rosea possess ergogenic properties? L/min; R: 124.8 +/- 7.7 L/min). All other parameters remained
Walker TB, Robergs RA. unchanged. PHASE II: Four-week R intake did not alter any of
Exercise Physiology Laboratory, University of New Mexico, the variables measured. CONCLUSION: Acute Rhodiola rosea
Albuquerque 87131, USA. intake can improve endurance exercise capacity in young
Rhodiola rosea is an herb purported to possess adaptogenic healthy volunteers. This response was not altered by prior
and ergogenic properties and has recently been the subject of daily 4-week Rhodiola intake.
increased interest The purpose of this article was to review
and summarize recent investigations of the potential Med Sci Sports Exerc. 2004 Mar;36(3):504-9.
performance-enhancing properties of Rhodiola rosea. Such Effects of a commercial herbal-based formula on exercise
studies have generated equivocal results. Several performance in cyclists.
investigations conducted in Eastern Europe have indicated Earnest CP, Morss GM, Wyatt F, Jordan AN, Colson S,
that Rhodiola rosea ingestion may produce such positive Church TS, Fitzgerald Y, Autrey L, Jurca R, Lucia A.
effects as improved cognitive function and reduced mental Center for Human Performance and Nutrition Research, The
fatigue. Other research from this region has illustrated Cooper Institute Center for Human Performance and Nutrition
enhanced endurance exercise performance in both humans Research, Dallas, TX 75230, USA. email@example.com
and rats. Studies conducted in Western Europe and in North INTRODUCTION/PURPOSE: We examined the effects of a
America have indicated that Rhodiola rosea may possess commercially marketed herbal-based formula purported to
substantial antioxidant properties but have produced mixed increase endurance on oxygen consumption (VO2) in 17
results when attempting to demonstrate an ergogenic effect competitive category III/IV amateur cyclists [mean (SEM) age:
during exercise in humans. 31.1 (1.8) yr; height: 178.5 (1.8) cm; weight: 77.1 (1.6) kg].
METHODS: Each cyclist participated in two (pre/post) cycling
De Bock K, Eijnde BO, Ramaekers M, Hespel P. tests progressing 25 W.4 min(-1) starting at 100 W
Acute Rhodiola rosea intake can improve endurance exercise administered in a randomized, placebo-controlled, double-
performance. blind fashion. The second trial was performed 14 d after the
Int J Sport Nutr Exerc Metab. 2004 Jun;14(3):298-307. ingestion of a manufacturer recommended loading phase (4 d
Faculty of Physical Education and Physiotherapy in the x 6 caps.d(-1)) and a maintenance phase (11 d x 3 caps.d(-1)).
Exercise Physiology and Biomechanics Laboratory at the Three treatment capsules contained 1000 mg of Cordyceps
Katholieke Universiteit Leuven, Tervuursevest 101, B-3001 sinensis (CS-4) and 300 mg Rhodiola rosea root extract as the
Leuven, Belgium. primary ingredients; 800 mg of other ingredients included
PURPOSE: The purpose of this study was to investigate the calcium pyruvate, sodium phosphate, potassium phosphate,
effect of acute and 4-week Rhodiola rosea intake on physical ribose, and adenosine and 200 mcg of chromium. RESULTS:
capacity, muscle strength, speed of limb movement, reaction Using a 2 x 2 ANOVA, we observed no significant treatment
time, and attention. METHODS: PHASE I: A double blind effect for any between or within group variables including
placebo-controlled randomized study (n= 24) was performed, peak VO2 [treatment 4.14 (0.2) L.min(-1); placebo 4.10 (0.2)
consisting of 2 sessions (2 days per session). Day 1: One L.min(-1)], time to exhaustion [treatment 38.47 (1.7) min;
hour after acute Rhodiola rosea intake (R, 200-mg Rhodiola placebo 36.95 (1.8) min], peak power output (PO) [treatment
Other Nutrients and Supplements / Page 34
300.00 (12.1) W; placebo 290.63 (12.9) W], or peak heart rate. prior to (59.9 +/- 5.9 vs. 59.1 +/- 5.4 ml/kg/min, respectively)
We also observed no differences for any subpeak exercise and following (60.1 +/- 5.5 vs. 57.1 +/- 5.8 ml/kg/min,
variable including the PO eliciting 2 mmol.L(-1) blood lactate respectively) the supplementation period. Ventilatory
(BLa) [treatment 201.00 (18.1) W; placebo 167.50 (19.2) W] and threshold (VT) was measured at 72 +/- 10% of VO(2peak) in P
4 mmol.L(-1) BLa [treatment 235.88 (15.8) W; placebo 244.78 and T prior to supplementation and did not change in either
(14.9) W], ventilatory threshold, respiratory compensation group following the supplementation. PLA completed the time
point, or Vo2 L.min(-1) gross efficiency at each stage. trial in 61.4+/- 2.4 min compared to 62.1+/- 4.0 min in T. Time
CONCLUSION: A 2-wk ingestion schema of a commercial trial measurements did not differ between groups, nor did they
herbal-based formula is insufficient to elicit positive changes change in response to supplementation. It is concluded that 5
in cycling performance. weeks of CordyMax Cs-4 supplementation has no effect on
aerobic capacity or endurance exercise performance in
J Strength Cond Res. 2005 May;19(2):358-63. endurance-trained male cyclists.
Cordyceps sinensis- and Rhodiola rosea-based
supplementation in male cyclists and its effect on muscle Med Sci Sports Exerc. 2003 Jun;35(6):987-94.
tissue oxygen saturation. Effects of ephedrine, caffeine, and their combination on
Colson SN, Wyatt FB, Johnston DL, Autrey LD, FitzGerald muscular endurance.
YL, Earnest CP. Jacobs I, Pasternak H, Bell DG.
Department of Health Sciences, McLennan Community Defence R&D Canada-Toronto, Canada. Ira.Jacobs@drdc-
College, Waco, Texas 76708, USA. firstname.lastname@example.org rddc.gc.ca
Cordyceps sinensis (Cs) and Rhodiola rosea (Rr) are herbs PURPOSE: The purpose of this study was to investigate the
used in traditional Chinese medicine to treat a multitude of effects of ingesting caffeine (C), ephedrine (E), and their
ailments as well as to enhance performance. The purpose of combination on muscular endurance, using a double-blind,
this research was to examine the effects of a formula repeated measures design. METHODS: Ninety minutes after
containing Cs and Rr (Cs-Rr) on circulatory dynamics, ingesting either C (4 mg x kg-1), E (0.8 mg x kg-1), a
specifically muscle tissue oxygen saturation (Sto(2)), in male combination of C+E, or a placebo (P), 13 male subjects
subjects during maximal exercise. This study followed a performed a weight-training circuit consisting of three
double blind, randomized, placebo-treatment, pre-post test supersets (SS), each SS consisting of leg press (at 80% of 1
design. Capsules were administered to 8 subjects who were RM to exhaustion) followed by bench press (at 70% 1-RM to
randomly assigned to 1 of 2 groups. The treatment group exhaustion); 2 min of rest intervened between SS. RESULTS:
received Cs-Rr, and the control group received a placebo. All The trials involving ephedrine ingestion (C+E and E), when
subjects performed 2 exercise stress tests to volitional fatigue compared with the nonephedrine trials (C and P), caused
on a cycle load ergometer. There were no significant (p </= significant increases (P < 0.05) in the mean number of
0.05) differences in Sto(2) slope, Sto(2) threshold (Sto(2T)), repetitions completed for both the leg-press and bench-press
Vo(2)max, ventilatory threshold (V(T)), or time to exhaustion exercises but only during the first SS. During that first set, the
(T(E)) between or within the treatment or control group. In mean number (+/-SD) of repetitions for leg press was 19 +/- 8,
conclusion, Cs-Rr did not significantly enhance Sto(2). 16 +/- 7, 14 +/- 6, and 13 +/- 5 for the C+E, E, C, and P trials,
respectively. The mean numbers of repetitions for the first set
Other Botanicals of bench-press exercise were 14 +/- 3, 13 +/- 3, 12 +/- 3, and 12
Int J Sport Nutr Exerc Metab. 2004 Apr;14(2):236-42. +/- 3 for the C+E, E, C, and P trials, respectively. As a result,
Cordyceps Sinensis (CordyMax Cs-4) supplementation does the total weight lifted during all three sets was greater for the
not improve endurance exercise performance. trials involving ephedrine ingestion. Systolic blood pressure
Parcell AC, Smith JM, Schulthies SS, Myrer JW, Fellingham G. before exercise was significantly increased with both
Human Performance Research Center at Brigham Young ephedrine treatment trials when compared with the other trials
Uninversity, Provo, UT 84602, USA. (C+E = 156 +/- 29 mm Hg; E = 150 +/- 14; C = 141 +/- 16; P =
It is purported that supplementation with Cordyceps Sinensis 138 +/- 14). CONCLUSION: It was concluded that acute
(CordyMax Cs-4) will improve oxidative capacity and ingestion of C+E and E increases muscular endurance during
endurance performance. The intent of this investigation was the first set of traditional resistance-training exercise. The
to examine the effects of CordyMax Cs -4 supplementation on performance enhancement was attributed primarily to the
VO<(2peak,) ventilatory threshold, and endurance effects of E; there was no additive effect of C.
performance in endurance-trained cyclists. Twenty-two male
cyclists participated in 5 weeks of supplementation with Ribose
CordyMax Cs-4 tablets (3 g/d). Training intensity was J Strength Cond Res. 2006 Aug;20(3):519-22.
maintained by weekly documentation and reporting Effects of ribose as an ergogenic aid.
throughout the 5-week period. Subjects completed a Peveler WW, Bishop PA, Whitehorn EJ.
VO(2peak) test and work-based time trial prior to and Department of Health and Kinesiology, Missis sippi
following the supplementation period. VO(2peak) was similar University for Women, Columbus, MS 39701, USA.
within and between placebo (PLA) and treatment (CS) groups email@example.com
Other Nutrients and Supplements / Page 35
The amount of adenosine triphosphate (ATP) stored in the Sports Medicine Center, Ohio State University, Columbus,
muscle available for immediate use is limited, and once used, OH, USA.
must be resynthesized in the muscle. Ribose, a naturally OBJECTIVE: It has been hypothesized that ribose
occurring pentose sugar, helps resynthesize ATP for use in supplementation rapidly replenishes adenosine triphosphate
muscles. There have been claims that ribose supplements stores and thereby improves exercise performance. We
increase ATP levels and improve performance. Other studies compared the effects of ribose versus dextrose on rowing
have provided mixed results on the effectiveness of ribose as performance. DESIGN: Double-blind randomized trial.
an ergogenic aid at high doses . None of these studies have SETTING: Rowing team training area of large midwestern
compared the impact of the recommended dose of ribose on university. PARTICIPANTS: Thirty-one women collegiate
athletes and nonathletes under exercise conditions that are rowers. INTERVENTIONS: We studied the effects of ribose
most conducive for effectiveness. The purpose of this study versus dextrose supplementation (10 g each in 8 oz water) for
was to evaluate the effectiveness of ribose as an ergogenic 8 weeks before and after practice and 2000-m time trials.
aid at the dose recommended for supplements currently on OUTCOME MEASUREMENTS AND RESULTS: In the time
the market during an exercise trial to maximize its efficacy. trials, the dextrose group showed significantly more
Male subjects (n = 11) performed 2 trials 1 week apart. Each improvement at 8 weeks than the ribose group (median, 15.2
trial consisted of three 30-second Wingate tests with a 2- vs. 5.2 s; P = 0.031). CONCLUSIONS: We doubt ribose
minute recovery between each test. Trials were impaired, and hypothesize dextrose enhanced, rowing
counterbalanced, with 1 trial being performed with 625 mg of performance. Further research is needed to define what role, if
ribose and the other with a placebo. Peak power, mean power, any, dextrose and ribose play as athletic supplements.
and percent decrease in power were recorded during each
Wingate test. Repeated-measures analysis of variance (p > Am J Physiol Regul Integr Comp Physiol. 2004
0.05) found no significant differences between ribose and Jan;286(1):R182-8.
placebo. These results suggest that ribose had no effect on Effect of ribose supplementation on resynthesis of adenine
performance when taken orally, at the dose suggested by the nucleotides after intense intermittent training in humans.
distributor. Hellsten Y, Skadhauge L, Bangsbo J.
Human Physiology, Copenhagen Muscle Research Centre,
Int J Sport Nutr Exerc Metab. 2005 Dec;15(6):653-64. Institute for Excersize and Sport Science, DK-2100
Effects of ribose supplementation prior to and during intense Copenhagen, Denmark. firstname.lastname@example.org
exercise on anaerobic capacity and metabolic markers. The effect of oral ribose supplementation on the resynthesis
Kerksick C, Rasmussen C, Bowden R, Leutholtz B, Harvey T, of adenine nucleotides and performance after 1 wk of intense
Earnest C, Greenwood M, Almada A, Kreider R. intermittent exercise was examined. Eight subjects performed a
Exercise and Sport Nutrition Laboratory, Center for Exercise, random double-blind crossover design. The subjects
Nutrition and Preventive Health Research, Dept of Health, performed cycle training consisting of 15 x 10 s of all-out
Human Performance and Recreation, Baylor University, Waco, sprinting twice per day for 7 days. After training the subjects
TX 76798-7313, USA. received either ribose (200 mg/kg body wt; Rib) or placebo
This study examined whether ribose supplementation before (Pla) three times per day for 3 days. An exercise test was
and during intense anaerobic exercise impacts anaerobic performed at 72 h after the last training session. Immediately
capacity and metabolic markers. Twelve moderately trained after the last training session, muscle ATP was lowered (P <
male cyclists (22.3 +/- 2.2 y; 181 +/- 6 cm, 74.8 +/- 9 kg) 0.05) by 25 +/- 2 and 22 +/- 3% in Pla and Rib, respectively. In
participated in the study. Subjects were familiarized and fasted both Pla and Rib, muscle ATP levels at 5 and 24 h after the
for 8 h after standardizing nutritional intake. In a double blind exercise were still lower (P < 0.05) than pretraining. After 72 h,
and crossover manner subjects ingested either a 150 mL muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6
placebo or ribose (3 g ribose + 150 microg folate). Subjects +/- 0.6 vs. 26.2 +/- 0.2 mmol/kg dry wt) but still lower (P < 0.05)
rested for 25 min and completed 5 x 30 s anaerobic capacity in Pla (21.1 +/- 0.5 vs. 26.0 +/- 0.2 mmol/kg dry wt) and higher
tests with 3 min passive rest. Six capillary blood samples were (P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after
taken prior to and after sprints for adenine nucleotide the test performed at 72 h were higher (P < 0.05) in Rib
breakdown determination. The experiment was repeated 1 wk compared with Pla. Mean and peak power outputs during the
later with alternative drink. Data were analyzed by repeated test performed at 72 h were similar (P > 0.05) in Pla and Rib.
measures ANOVA. No significant interactions were observed The results support the hypothesis that the availability of
for any performance or blood variables. D-ribose ribose in the muscle is a limiting factor for the rate of
supplementation has no impact on anaerobic exercise capacity resynthesis of ATP. Furthermore, the reduction in muscle
and metabolic markers after high-intensity cycling exercise. ATP observed after intense training does not appear to be
limiting for high-intensity exercise performance.
Clin J Sport Med. 2006 Jan;16(1):68-71.
Ribose versus dextrose supplementation, association with Int J Sport Nutr Exerc Metab. 2003 Mar;13(1):76-86.
rowing performance: a double-blind study. Effects of oral D-ribose supplementation on anaerobic
Dunne L, Worley S, Macknin M. capacity and selected metabolic markers in healthy males.
Other Nutrients and Supplements / Page 36
Kreider RB, Melton C, Greenwood M, Rasmussen C, both Pla and Rib, muscle ATP levels at 5 and 24 h after the
Lundberg J, Earnest C, Almada A. exercise were still lower (P < 0.05) than pretraining. After 72 h,
Exercise and Sport Nutrition Laboratory, Center for Exercise, muscle ATP was similar (P > 0.05) to pretraining in Rib (24.6
Nutrition and Preventative Health, in the Department of +/- 0.6 vs. 26.2 +/- 0.2 mmol/kg dry wt) but still lower (P < 0.05)
Health, Human Performance and Recreation at Baylor in Pla (21.1 +/- 0.5 vs. 26.0 +/- 0.2 mmol/kg dry wt) and higher
University, Waco, TX 76798-7313, USA. (P < 0.05) in Rib than in Pla. Plasma hypoxanthine levels after
Oral D-ribose supplementation has been reported to increase the test performed at 72 h were higher (P < 0.05) in Rib
adenine nucleotide synthesis and exercise capacity in certain compared with Pla. Mean and peak power outputs during the
clinical populations. Theoretically, increasing adenine test performed at 72 h were similar (P > 0.05) in Pla and Rib.
nucleotide availability may enhance high intensity exercise The results support the hypothesis that the availability of
capacity. This study evaluated the potential ergogenic value ribose in the muscle is a limiting factor for the rate of
of D-ribose supplementation on repetitive high-intensity resynthesis of ATP. Furthermore, the reduction in muscle
exercise capacity in 19 trained males. Subjects were ATP observed after intense training does not appear to be
familiarized to the testing protocol and performed two limiting for high-intensity exercise performance.
practice-testing trials before pre-supplementation testing.
Each test involved warming up for 5 min on a cycle ergometer Int J Sport Nutr Exerc Metab. 2003 Mar;13(1):76-86.
and then performing two 30-s Wingate anaerobic sprint tests Effects of oral D-ribose supplementation on anaerobic
on a computerized cycle ergometer separated by 3 min of rest capacity and selected metabolic markers in healthy males.
recovery. In the pre- and post-supplementation trials, blood Kreider RB, Melton C, Greenwood M, Rasmussen C,
samples were obtained at rest, immediately following the first Lundberg J, Earnest C, Almada A.
and second sprints, and following 5 min of recovery from Exercise and Sport Nutrition Laboratory, Center for Exercise,
exercise. Subjects were then matched according to body mass Nutrition and Preventative Health, in the Department of
and anaerobic capacity and assigned to ingest, in a Health, Human Performance and Recreation at Baylor
randomized and double blind manner, capsules containing University, Waco, TX 76798-7313, USA.
either 5 g of a dextrose placebo (P) or D-ribose (R) twice daily Oral D-ribose supplementation has been reported to increase
(10 g/d) for 5 d. Subjects then performed post- adenine nucleotide synthesis and exercise capacity in certain
supplementation tests on the 6th day. Data were analyzed by clinical populations. Theoretically, increasing adenine
ANOVA for repeated measures. Results revealed a significant nucleotide availability may enhance high intensity exercise
interaction (p =.04) in total work output. Post hoc analysis capacity. This study evaluated the potential ergogenic value
revealed that work significantly declined (-18 +/- 51 J) during of D-ribose supplementation on repetitive high-intensity
the second post-supplementation sprint in the P group while exercise capacity in 19 trained males. Subjects were
being maintained in the R group (-0.0 +/- 31 J). No significant familiarized to the testing protocol and performed two
interactions were observed in peak power, average power, practice-testing trials before pre-supplementation testing.
torque, fatigue index, lactate, ammonia, glucose, or uric acid. Each test involved warming up for 5 min on a cycle ergometer
Results indicate that oral ribose supplementation (10 g/d for 5 and then performing two 30-s Wingate anaerobic sprint tests
d) does not affect anaerobic exercise capacity or metabolic on a computerized cycle ergometer separated by 3 min of rest
markers in trained subjects as evaluated in this study. recovery. In the pre- and post-supplementation trials, blood
samples were obtained at rest, immediately following the first
Am J Physiol Regul Integr Comp Physiol. 2004 and second sprints, and following 5 min of recovery from
Jan;286(1):R182-8. exercise. Subjects were then matched according to body mass
Effect of ribose supplementation on resynthesis of adenine and anaerobic capacity and assigned to ingest, in a
nucleotides after intense intermittent training in humans. randomized and double blind manner, capsules containing
Hellsten Y, Skadhauge L, Bangsbo J. either 5 g of a dextrose placebo (P) or D-ribose (R) twice daily
Human Physiology, Copenhagen Muscle Research Centre, (10 g/d) for 5 d. Subjects then performed post-
Institute for Excersize and Sport Science, DK-2100 supplementation tests on the 6th day. Data were analyzed by
Copenhagen, Denmark. email@example.com ANOVA for repeated measures. Results revealed a significant
The effect of oral ribose supplementation on the resynthesis interaction (p =.04) in total work output. Post hoc analysis
of adenine nucleotides and performance after 1 wk of intense revealed that work significantly declined (-18 +/- 51 J) during
intermittent exercise was examined. Eight subjects performed a the second post-supplementation sprint in the P group while
random double-blind crossover design. The subjects being maintained in the R group (-0.0 +/- 31 J). No significant
performed cycle training consisting of 15 x 10 s of all-out interactions were observed in peak power, average power,
sprinting twice per day for 7 days. After training the subjects torque, fatigue index, lactate, ammonia, glucose, or uric acid.
received either ribose (200 mg/kg body wt; Rib) or placebo Results indicate that oral ribose supplementation (10 g/d for 5
(Pla) three times per day for 3 days. An exercise test was d) does not affect anaerobic exercise capacity or metabolic
performed at 72 h after the last training session. Immediately markers in trained subjects as evaluated in this study.
after the last training session, muscle ATP was lowered (P <
0.05) by 25 +/- 2 and 22 +/- 3% in Pla and Rib, respectively. In J Strength Cond Res. 2003 Feb;17(1):47-52.
Other Nutrients and Supplements / Page 37
Effects of ribose supplementation on repeated sprint (P = 0.003). At day 10, by Mann-Whitney U test of changes,
performance in men. the placebo group had significantly greater increases in IL-6
Berardi JM, Ziegenfuss TN. and CRP than the treatment group (P = 0.05 and P < 0.01),
Applied Physiology Laboratory, Eastern Michigan University, respectively. CONCLUSION: This study suggested that
Ypsilanti, Michigan 48197, USA. firstname.lastname@example.org exercise-induced inflammation, evaluated by changes in IL-6
This study used a randomized, placebo-controlled, crossover and CRP, was significantly reduced by the dietary
design to evaluate the effects of oral ribose supplementation supplement.
on short-term anaerobic performance. After familiarization,
subjects performed 2 bouts of repeated cycle sprint exercise J Nutr Sci Vitaminol (Tokyo). 2003 Jun;49(3):163-7. Related
(six 10-second sprints with 60-second rest periods between Articles, Links
sprints) in a single day. After the second exercise, bout (-)-Hydroxycitric acid ingestion increases fat utilization
subjects ingested 32 g of ribose or cellulose (4 x 8-g doses) during exercise in untrained women.
during the next 36 hours. After supplementation, subjects Lim K, Ryu S, Nho HS, Choi SK, Kwon T, Suh H, So J, Tomita
returned to the laboratory to perform a single bout of cycle K, Okuhara Y, Shigematsu N.
sprinting (as described above). After a 5-day washout period, Department of Physical Education, Konkuk University, Seoul,
subjects repeated the protocol, receiving the opposite Korea. email@example.com
supplement treatment. Ribose supplementation lead to (-)-Hydroxycitric acid (HCA) is a competitive inhibitor of the
statistically significant increases in mean power and peak enzyme ATPcitrate-lyase, which inhibits lipogenesis in the
power in sprint 2 (10.9 and 6.6%, respectively) and higher body. Moreover, HCA increases endurance exercise
(although not significant) absolute values in sprints 1, 3, and performance in trained mice and athletes. However, had not
4. In conclusion, ribose supplementation did not show been investigated in untrained animals and humans.
reproducible increases in performance across all 6 sprints. Therefore, we investigated the effects of short-term HCA
Therefore, within the framework of this investigation, it ingestion on endurance exercise performance and fat
appears that ribose supplementation does not have a metabolism in untrained women. In two experiments designed
consistent or substantial effect on anaerobic cycle sprinting. as a double-blind crossover test, six subjects ingested 250 mg
of HCA or placebo (same amount of dextrin) via capsule for 5
Other Supplements d and then participated in cycle ergometer exercise. They
Med Sci Sports Exerc. 2003 Dec;35(12):2032-7. cycled at 40% VO2max for 1 h and then the exercise intensity
A dietary supplement attenuates IL-6 and CRP after eccentric was increased to 60% VO2max until exhaustion on day 5 of
exercise in untrained males. each experiment. HCA tended to decrease the respiratory
Phillips T, Childs AC, Dreon DM, Phinney S, Leeuwenburgh exchange ratio (RER) and carbohydrate oxidation during 1 h of
C. exercise. In addition, exercise time to exhaustion was
University of Florida, Biochemistry of Aging Laboratory, significantly enhanced (p<0.05). These results suggest that
College of Health and Human Performance, Center for Exercise HCA increases fat metabolism, which may be associated with
Science, College of Medicine, Gainesville 32611, USA. a decrease in glycogen utilization during the same intensity
PURPOSE: This study investigated the effects of a dietary exercise and enhanced exercise performance.
supplement on exercise-induced markers of cell damage and
the inflammatory mediators C-reactive protein (CRP) and J Strength Cond Res. 2003 Aug;17(3):455-62.
interleukin-6 (IL-6). METHODS: The supplement contained The effects of L-carnitine L-tartrate supplementation on
mixed tocopherols, flavonoids, and docosahexaenoate. Forty hormonal responses to resistance exercise and recovery.
healthy, nonsmoking, untrained males (aged 18-35 yr) were Kraemer WJ, Volek JS, French DN, Rubin MR, Sharman MJ,
randomly assigned to receive either the supplement (N = 20) Gomez AL, Ratamess NA, Newton RU, Jemiolo B, Craig BW,
or placebo (N = 20) during the 14-d experimental protocol. Hakkinen K.
Blood samples were collected on day 0 (baseline), day 7 Human Performance Laboratory, Department of Kinesiology,
(eccentric exercise-induced injury), day 10, and day 14. University of Connecticut, Storrs, CT 06269, USA.
OBJECTIVE: Markers of cell damage (creatine kinase (CK) and firstname.lastname@example.org
lactate dehydrogenase (LDH)) and inflammation IL-6 and CRP The purpose of this investigation was to examine the
were assessed at these time points in conjunction with influence of L-carnitine L-tartrate (LCLT) supplementation
subjective range of motion (ROM) and perceived pain using a balanced, cross-over, placebo-controlled research
measurements. Statistical analyses were conducted using design on the anabolic hormone response (i.e., testosterone
nonparametric methods (P < 0.05). RESULTS: Eccentric arm [T], insulin-like growth factor-I, insulin-like growth factor-
curl exercise was used to induce an acute phase injury binding protein-3 [IGFBP-3], and immunofunctional and
response as evidenced by significant (P < 0.0001) increases in immunoreactive growth hormone [GHif and GHir]) to acute
CK, LDH, and pain, as well as a decreased range of motion 3 d resistance exercise. Ten healthy, recreationally weight-trained
after the exercise. There were no significant differences men (mean +/- SD age 23.7 +/- 2.3 years, weight 78.7 +/- 8.5 kg,
between groups in CK and LDH responses. In contrast, there and height 179.2 +/- 4.6 cm) volunteered and were matched,
were significant group differences for IL-6 (P = 0.008) and CRP and after 3 weeks of supplementation (2 g LCLT per day),
Other Nutrients and Supplements / Page 38
fasting morning blood samples were obtained on six associated alterations in immune cell function in athletes with
consecutive days (D1-D6). Subjects performed a squat balanced magnesium status.
protocol (5 sets of 15-20 repetitions) on D2. During the squat
protocol, blood samples were obtained before exercise and 0, Caffeine
15, 30, 120, and 180 minutes postexercise. After a 1-week J Appl Physiol. 2002 Oct;93(4):1227-34.
washout period, subjects consumed the other supplement for Exercise endurance 1, 3, and 6 h after caffeine ingestion in
a 3-week period, and the same experimental protocol was caffeine users and nonusers.
repeated using the exact same procedures. Expected exercise- Bell DG, McLellan TM.
induced increases in all of the hormones were observed for Defence R&D Canada-Toronto, Toronto, Ontario, Canada
GHir, GHif, IGFBP-3, and T. Over the recovery period, LCLT M3M 3B9. email@example.com
reduced the amount of exercise-induced muscle tissue The purpose of the present study was to examine the duration
damage, which was assessed via magnetic resonance imaging of caffeine's ergogenic effect and whether it differs between
scans of the thigh. LCLT supplementation significantly (p < users and nonusers of the drug. Twenty-one subjects (13
0.05) increased IGFBP-3 concentrations prior to and at 30, 120, caffeine users and 8 nonusers) completed six randomized
and 180 minutes after acute exercise. No other direct effects of exercise rides to exhaustion at 80% of maximal oxygen
LCLT supplementation were observed on the absolute consumption after ingesting either a placebo or 5 mg/kg of
concentrations of the hormones examined, but with more caffeine. Exercise to exhaustion was completed once per week
undamaged tissue, a greater number of intact receptors would at either 1, 3, or 6 h after placebo or drug ingestion. Exercise
be available for hormonal interactions. These data support the time to exhaustion differed between users and nonusers with
use of LCLT as a recovery supplement for hypoxic exercise the ergogenic effect being greater and lasting longer in
and lend further insights into the hormonal mechanisms that nonusers. For the nonusers, exercise times 1, 3, and 6 h after
may help to mediate quicker recovery. caffeine ingestion were 32.7 +/- 8.4, 32.1 +/- 8.6, and 31.7 +/-
12.0 min, respectively, and these values were each
Magnes Res. 2003 Mar;16(1):49-58. significantly greater than the corresponding placebo values of
Effect of magnesium on granulocyte function and on the 24.2 +/- 6.4, 25.8 +/- 9.0, and 23.2 +/- 7.1 min. For caffeine
exercise induced inflammatory response. users, exercise times 1, 3, and 6 h after caffeine ingestion were
Mooren FC, Golf SW, Volker K. 27.4 +/- 7.2, 28.1 +/- 7.8, and 24.5 +/- 7.6 min, respectively. Only
Department of Sports Medicine, Westfalis che Wilhelms- exercise times 1 and 3 h after drug ingestion were significantly
Universitat Munster, 48129 Munster, Germany. mooren@uni- greater than the respective placebo trials of 23.3 +/- 6.5, 23.2
muenster.de +/- 7.1, and 23.5 +/- 5.7 min. In conclusion, both the duration
Magnesium status is a well-known modulator of the immune and magnitude of the ergogenic effect that followed a 5 mg/kg
system. In the present study we investigated the effect of dose of caffeine were greater in the nonusers compared with
magnesium on granulocyte signalling and function. the users.
Furthermore, we performed a double-blinded randomised
study investigating the effect of a two-month magnesium Pain. 2004 Jun;109(3):291-8.
supplementation period on the exercise-associated alterations Dose-dependent effect of caffeine on reducing leg muscle
in immune function. In vitro incubation of granulocytes in pain during cycling exercise is unrelated to systolic blood
media of different magnesium composition resulted in pressure.
significant changes in chemotactic peptide-induced calcium O'Connor PJ, Motl RW, Broglio SP, Ely MR.
transients while basal calcium levels were not affected. Department of Exercise Science, University of Georgia, 115-L
Likewise, the stimulus-induced formation of free radicals was Ramsey Center, Athens, GA 30602-6554, USA.
affected by extracellular magnesium while phagocytosis of firstname.lastname@example.org
granulocytes was not affected. In the second part of the This double-blind, within-subjects experiment examined the
study we investigated whether a two-month period of effects of ingesting two doses of caffeine on perceptions of
magnesium supplementation was able to diminish alterations leg muscle pain and blood pressure during moderate intens ity
in immune cell counts and functions after an exercise test until cycling exercise. Low caffeine consuming college-aged males
exhaustion. The magnesium status was similar in both human (N=12) ingested one of two doses of caffeine (5 or 10 mg.kg(-
and placebo groups and did not change significantly after the 1) body weight) or placebo and 1 h later completed 30 min of
supplementation period. Exhaustive exercise induced an moderate intensity cycling exercise (60% VO2peak). The order
activation of the immune system as indicated by an increase of drug administration was counter-balanced. Resting blood
in granulocyte count and a post-exercise lymphopenia. In pressure and heart rate were recorded immediately before and
addition, chemotactic peptide-induced cellular calcium 1 h after drug administration. Perceptions of leg muscle pain
transients were enhanced post-exercise while oxidative burst as well as work rate, blood pressure, heart rate, and oxygen
and phagocytosis were decreased. These results suggest that uptake (VO2) were recorded during exercise. Caffeine
magnesium is an important modulator of immune cell function increased resting systolic pressure in a dose-dependent
under in vitro conditions. However, a magnesium fashion but these blood pressure effects were not maintained
supplementation seems to be unable to prevent any exercise- during exercise. Caffeine had a significant linear effect on leg
Other Nutrients and Supplements / Page 39
muscle pain ratings [F(2,22)=14.06; P < 0.0001; eta2=0.56 ]. The significantly lower in CC (3.8 micro g/ml) compared with CP
mean (+/-SD) pain intensity scores during exercise after (6.8 micro g/ml). Plasma paraxanthine increased in a dose-
ingesting 10 mg.kg(-1) body weight caffeine, 5 mg.kg(-1) body dependent fashion and did not peak during exercise. In
weight caffeine, and placebo were 2.1+/-1.4, 2.6+/-1.5, and conclusion, dividing a caffeine dose provides no ergogenic
3.5+/-1.7, respectively. The results support the conclusion effect over a bolus dose but reduces postexercise urinary
that caffeine ingestion has a dose-response effect on concentration.
reducing leg muscle pain during exercise and that these
effects do not depend on caffeine-induced increases in Int J Sport Nutr Exerc Metab. 2002 Dec;12(4):438-52.
systolic blood pressure during exercise. Caffeine ingestion does not alter performance during a 100-km
cycling time-trial performance.
J Pain. 2003 Aug;4(6):316-21. Hunter AM, St Clair Gibson A, Collins M, Lambert M, Noakes
Effect of caffeine on perceptions of leg muscle pain during TD.
moderate intensity cycling exercise. Department of Sports Studies, University of Stirling, Stirling,
Motl RW, O'Connor PJ, Dishman RK. FK9 4LA Scotland, UK.
University of Georgia, Department of Exercise Science, This study analyzed the effect of caffeine ingestion on
University of Georgia, Athens, GA 30602-6554, USA. performance during a repeated-measures, 100-km, laboratory
email@example.com cycling time trial that included bouts of 1- and 4-km high
This double-blind, within-subjects experiment examined the intensity epochs (HIE). Eight highly trained cyclists
effect of ingesting a large dose of caffeine on perceptions of participated in 3 separate trials' placebo ingestion before
leg muscle pain during moderate intensity cycling exercise. exercise with a placebo carbohydrate solution and placebo
Low-caffeine-consuming college-aged males (n = 16) ingested tablets during exercise (Pl), or placebo ingestion before
either caffeine (10 mg x kg(-1) body weight) or placebo and 1 exercise with a 7% carbohydrate drink and placebo tablets
hour later completed 30 minutes of moderate intensity cycling during exercise (Cho), or caffeine tablet inges tion before and
exercise (60% VO(2peak)). The order of drug administration during exercise with 7% carbohydrate (Caf). Placebo (twice) or
was counter-balanced. Perceptions of leg muscle pain as well 6 mg.kg(-1) caffeine was ingested 60 min prior to starting 1 of
as work rate, heart rate, and oxygen uptake (VO(2)) were the 3 cycling trials, during which subjects ingested either
recorded during exercise. Leg muscle pain ratings were additional placebos or a caffeine maintenance dose of 0.33
significantly and moderately reduced after a high dose of mg.kg(-1) every 15 min to trial completion. The 100-km time
caffeine. This observation suggests that prior reports trial consisted of five 1-km HIE after 10, 32, 52, 72, and 99 km,
showing caffeine improves endurance exercise performance as well as four 4-km HIE after 20, 40, 60, and 80 km. Subjects
might be partially explained by caffeine's hypoalgesic were instructed to complete the time trial and all HIE as fas t as
properties. It also suggests that moderate intensity cycling possible. Plasma (caffeine) was significantly higher during Caf
exercise has promise as a useful experimental model for the (0.43 +/- 0.56 and 1.11 +/- 1.78 mM pre vs. post Pl; and 47.32
study of naturally occurring muscle pain. +/- 12.01 and 72.43 +/- 29.08 mM pre vs. post Caf). Average
power, HIE time to completion, and 100-km time to completion
J Appl Physiol. 2003 Apr;94(4):1557-62. Epub 2002 Dec 13. were not different between trials. Mean heart rates during
Effect of a divided caffeine dose on endurance cycling both the 1-km HIE (184.0 +/- 9.8 Caf; 177.0 +/- 5.8 Pl; 177.4 +/-
performance, postexercise urinary caffeine concentration, and 8.9 Cho) and 4-km HIE (181.7 +/- 5.7 Caf; 174.3 +/- 7.2 Pl; 175.6
plasma paraxanthine. +/- 7.6 Cho; p <.05) was higher in Caf than in the other groups.
Conway KJ, Orr R, Stannard SR. No significant differences were found between groups for
School of Exercise and Sport Science, University of Sydney, either EMG amplitude (IEMG) or mean power frequency
Lidcombe 1825, New South Wales, Australia. spectrum (MPFS). IEMG activity and performance were not
This study compared the effects of a single and divided dose different between groups but were both higher in the 1-km
of caffeine on endurance performance and on postexercise HIE, indicating the absence of peripheral fatigue and the
urinary caffeine and plasma paraxanthine concentrations. Nine presence of a centrally-regulated pacing strategy that is not
male cyclists and triathletes cycled for 90 min at 68% of altered by caffeine ingestion. Caffeine may be without
maximal oxygen uptake, followed by a self-paced time trial ergogenic benefit during endurance exercise in which the
(work equivalent to 80% of maximal oxygen uptake workload athlete begins exercise with a defined, predetermined goal
over 30 min) with three randomized, balanced, and double- measured as speed or distance.
blind interventions: 1) placebo 60 min before and 45 min into
exercise (PP); 2) single caffeine dose (6 mg/kg) 60 min before Med Sci Sports Exerc. 2003 Aug;35(8):1348-54.
exercise and placebo 45 min into exercise (CP); and 3) divided Effect of repeated caffeine ingestion on repeated exhaustive
caffeine dose (3 mg/kg) 60 min before and 45 min into exercise exercise endurance.
(CC). Time trial performance was unchanged with caffeine Bell DG, McLellan TM.
ingestion (P = 0.08), but it tended to be faster in the caffeine Operational Medicine Section, Defence R&D Canada-
trials (CP: 24.2 min and CC: 23.4 min) compared with placebo Toronto, Ontario, Canada. firstname.lastname@example.org
(PP: 28.3 min). Postexercise urinary caffeine concentration was
Other Nutrients and Supplements / Page 40
PURPOSE: The purpose of this study was to examine the Department of Sport, Exercise and Biomedical Sciences,
effect of repeated doses of caffeine on repeated exercise University of Luton, United Kingdom.
endurance.METHODS Nine male caffeine users performed email@example.com
exercise rides (ER) to exhaustion at 80% VO(2max) after PURPOSE: The purpose of this investigation was to assess
ingesting a placebo, 5 mg x kg-1 of caffeine, or 2.5 mg x kg-1 of the acute effects of caffeine ingestion on short-term, high-
caffeine 1 h before the ER. Two ER were performed weekly on intensity exercise (ST) after a period of oral creatine
the same day once in the morning (AM) and 5 h later in the supplementation and caffeine abstinence. METHODS:
afternoon (PM). There were four treatments containing either Fourteen trained male subjects performed treadmill running to
caffeine or placebo, i.e., trial A representing 5-mg x kg-1 volitional exhaustion (T(lim)) at an exercise intensity
caffeine in the AM and 2.5-mg x kg-1 caffeine in the PM; trial equivalent to 125% VO(2max). Three trials were performed,
B, which was placebo in both AM and PM; trial C one before 6 d of creatine loading (0.3 g x kg x d(-1) baseline),
representing 5-mg x kg-1 caffeine in the AM and placebo in and two further trials after the loading period. One hour before
the PM; and trial D representing a placebo in the AM and 5- the postloading trials, caffeine (5 mg x kg(-1)) or placebo was
mg x kg-1 caffeine in the PM. The order of the treatment trials orally ingested in a cross-over, double-blind fashion. Four
was double blind and randomized. RESULTS: Caffeine measurements of rating of perceived exertion were taken, one
ingestion significantly increased exercise time to exhaustion in every 30 s, during the first 120 s of the exercise. Blood
the AM (trial A 24.9 +/- 10.2 min and trial C 21.8 +/- 4.9 vs trial samples were assayed for lactate, glucose, potassium, and
B 18.0 +/- 6.4 min and D 17.7 +/- 4.3 min). This effect was catecholamines, immediately before and after exercise.
maintained in the PM and greater than placebo (B 18.3 +/- 4.8 RESULTS: Body mass increased (P < 0.05) over the creatine
min) regardless of whether redosing (trial A 21.5 +/- 8.6 min) or supplementation period, and this increase was maintained for
placebo (trial C 21.0 +/- 6.8) followed the initial morning dose. both caffeine and placebo trials. There was no increase in the
Caffeine dosing in the PM (trial D 22.4 +/- 7.2 min) also maximal accumulated oxygen deficit between trials; however,
increased ER after placebo trial D in the AM. CONCLUSIONS: total VO(2) was significantly increased in the caffeine trial in
It was concluded that redosing with caffeine after exhaustive comparison with the placebo trial (13.35 +/- 3.89 L vs 11.67 +/-
exercise in the AM was not necessary to maintain the 3.61 L). In addition, caffeine T(lim) (222.1 +/- 48.9 s) was
ergogenic effect of the drug during subsequent exercise 6 h significantly greater (P < 0.05) than both baseline (200.8 +/-
later. 33.4 s) and placebo (198.3 +/- 45.4 s) T(lim). RPE was also
lower at 90 s in the caffeine treatment (13.8 +/- 1.8 RPE points)
Med Sci Sports Exerc. 2002 Nov;34(11):1785-92. in comparison with baseline (14.6 +/- 1.9 RPE points).
Caffeine is ergogenic after supplementation of oral creatine CONCLUSION: As indicated by a greater T(lim), acute
monohydrate. caffeine ingestion was found to be ergogenic after 6-d of
Doherty M, Smith PM, Davison RC, Hughes MG. creatine supplementation and caffeine abstinence.
Other Nutrients and Supplements / Page 41