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									BIOENERGETICS OF TRAINING;
ENDOCRINE RESPONSE


  PEP 3136: Exercise Leadership II

  Dr. Michael Hartman, CSCS*D
Introduction:
   Metabolism
       Total of all chemical reactions that occur in the body

       Anabolic reactions
           Synthesis of molecules
       Catabolic reactions
           Breakdown of molecules


   Bioenergetics
       Converting food nutrients (fats, proteins, carbohydrates) into
        energy
Nutrients: Energy supply for the body
   There are different nutrients used to produce energy
    for metabolism
       Carbohydrates: 4 kcal/g
       Fat: 9 kcal/g
       Protein: 4.1 kcal/g


   Carbohydrates (CHO) can be metabolized under
    aerobic and anaerobic conditions

   Proteins and fat require oxygen to be metabolized
Nutrients: Energy storage

   Carbohydrates
       Glucose
           Stored as glycogen


   Fats
       Primarily fatty acids
           Stored as triglycerides


   Proteins
     Amino acids
     Not a primary energy source
Bioenergetics: ATP

   The chemical energy produced from nutrient sources, used as a
    universal cellular energy, is adenosine triphosphate (ATP).

   ATP consists of adenine, a 5-carbon sugar called ribose, and
    three linked phosphates, symbolized by Pi (inorganic
    phosphate).
                                                                adenine
                                                                   NH2

                                                            N
                                                                       N
                          O        O        O
                     HO   P    O   P    O   P    O          N      N
                                                       O
                          OH       OH       OH

                               triphosphate
                                                     OH    OH

                                                     ribose
Bioenergetics: ATP
   Energy stored in the chemical bonds of adenosine
    triphosphate (ATP) is used to power muscular
    activity.

   The replenishment of ATP in human skeletal muscle is
    accomplished by three basic energy systems:
     Phosphagen   (ATP-PCr)
     Glycolytic

     Oxidative
Bioenergetics: ATP

   Formation of ATP
       Phosphocreatine (PC) breakdown
       Degradation of glucose and glycogen (glycolysis)
       Oxidative formation of ATP

   Anaerobic pathways
       Does not involve O2
       PC breakdown and glycolysis

   Aerobic pathways
       Requires O2
       Oxidative phosphorylation
Bioenergetics: ATP
   Breakdown:     ATP   ATPase     ADP + Pi + Energy




   Formation:   ADP + Pi  ATP


                                  work

                                          synthesis
                 mechanical
                              transport
Energy Systems:
   The different energy systems of the human body are used
    regarding to different energetic demands

                                           •Phosphagen (ATP-PCr)
                                           •Glycolysis
                                           •Oxidative
Energy Usage:
   In general, an inverse relationship exists between
    the relative rate and total amount of ATP that a
    given energy system can produce.

   As a result, the phosphagen energy system
    primarily supplies ATP for high-intensity activities of
    short duration, the glycolytic system for moderate-
    to high-intensity activities of short to medium
    duration, and the oxidative system for low-intensity
    activities of long duration.
   Energy Usage:

Duration     Intensity      Primary Energy System(s)
0-10 s       Very intense   Phosphagen

11-30 s      Intense        Phosphagen and Fast
                            Glycolysis

30 s-2 min   Heavy          Fast Glycolysis

2-3 min      Moderate       Fast Glycolysis and
                            Oxidative System

> 3 min      Light          Oxidative System
 Energy production:

System                 Rate of ATP       Capacity of ATP
Phosphagen             1                 5

Fast glycolysis        2                 4

Slow glycolysis        3                 3

Oxidation (CHO)        4                 2

Oxidation (FAT, PRO)   5                 1

                                 1 = fastest/greatest; 5 = slowest/least
Energy Usage:
   The extent to which each of the three energy
    systems contributes to ATP production depends
    primarily on the intensity of muscular activity and
    secondarily on the duration.

   At no time, during either exercise or rest, does any
    single energy system provide the complete supply
    of energy.
Aerobic vs. Anaerobic Energy:

   Energy to perform exercise comes from an interaction
    between aerobic and anaerobic pathways
   Exercise intensity is the most important variable
    related to which energy system is activated to
    produce ATP for muscular work

   Effect of Duration and Intensity

       Short-term, high-intensity activities
         Greater contribution of anaerobic energy systems


       Long-term, low to moderate-intensity exercise
         Majority of ATP produced from aerobic sources
Endocrine Response
Introduction:
   It has been theorized
    that the endocrine
    system can be
    manipulated naturally
    with resistance
    training to enhance
    the development of
    various target tissues,
    thereby improving
    performance.
    Endocrine Glands:
   Secrete substances (hormones) into blood or body fluid; Promotes
    homeostasis; Tissue adaptations are related to endocrine responses to
    exercise

   Hormones function in reproduction; growth and development;
    energy production, utilization, and storage; immunity

   Peptide hormones (protein)- indirectly effects cell function by
    binding to a hormone receptor

   Steroid hormones (fat)- directly effect the DNA in the nucleus of
    a cell
    Hormonal Response to
    Heavy Resistance Training
   Hormonal secretions related to
     Amount and type of stress
     Metabolic demands of exercise
     Changes in resting metabolism


   Hormonal response occurs only in tissue exercised
    Mechanisms of Hormone Interaction
   Increased concentration of hormones facilitates
    interaction

     Recoveryfrom anaerobic exercise promotes cell
     growth (anabolism)

     Inappropriate exercise prescriptions can result
     in a net catabolic effect
Hormones Vital to Exercise

   Testosterone
   Cortisol
   Growth hormone
   Insulin and glucagons
   Epinephrine
   Norepinephrine
Testosterone
   Steroid hormone
   Produced primarily by the Leydig cells in the male
    testes
   Regulated by the hypothalamic-pituitary axis
Testosterone (cont.)
   Circulating testosterone in females is about 10% of
    that in males and comes from the ovaries and the
    adrenal cortex
   During maturation, testosterone contributes to many
    of the male sexual characteristics associated with
    development
Cortisol
   Steroid hormone
   Secreted by the outer layer of the adrenal glands
   Sometimes called stress hormone
   Ensures availability of energy by increasing production
    of glucose, decreasing glucose uptake, increasing
    glycogen production in skeletal muscle, and causing
    amino acids to be mobilized from skeletal muscle
Growth Hormone
   Polypeptide hormone
   Consists of 191 amino acids and two disulfide bonds
   Produced and secreted from the anterior pituitary
    gland
   Many variations exist
Growth Hormone (cont.)
   Associated with growth properties
   Exerts tremendous influence on the metabolic system
    and energy availability
   Increases muscle uptake of amino acids as well as the
    breakdown of lipids via lipolysis
Insulin and Glucagons
   Insulin
     – 51 amino acid peptide hormone

     – Produced by the beta cells of the pancreas

     – Consists of a 21-amino acid A-chain and a 30-
       amino acid B-chain connected by two disulfide
       bonds
   Glucagon
     – Polypeptide chain 29 amino acids long

     – Produced by the alpha cells of the pancreas
Insulin and Glucagons (cont.)

   Both are released in response to increasing or
    decreasing blood glucose levels
   Both are under control by epinephrine and
    norepinephrine from the sympathetic nervous system,
    causing insulin to decrease and glucagon to increase
Epinephrine
   Sometimes called adrenaline
   An amine neurohormone
   Serves as a neurotransmitter in the central nervous
    system and transmits signals between the synapses of
    nerve cells
Epinephrine (cont.)
   Plays a big role in the circulation by interacting with
    a variety of alpha and beta receptors in many
    different tissues in the body
   Responsible for many of the “fight-or-flight”
    responses
Norepinephrine
   Also known as noradrenaline
   An amine neurohormone
   Comes from spillover from sympathetic nervous
    system synapses
   Sometimes considered an indicator of sympathetic
    nervous system activity
Acute and Chronic Training Adaptations

   Regular training and physical activity result in an
    adaptation of the body to accommodate stresses on the
    body

   Up-regulation: refers to an increase in the number of
    receptors on the surface of target cells, making the cells
    more sensitive to a hormone or other molecule
   Down-regulation: a decrease in the number of receptors
    on the surface of target cells, making the cells less
    sensitive to a hormone or other molecule
The Hormonal System and Acute Responses
to Resistance Exercise

  Acute Training Variables for Resistance Training
 1.   Choice of exercise
 2.   Order of exercise
 3.   Volume of exercise
 4.   Intensity (or load) of exercise
 5.   Inter-set rest intervals
Key Point

During heavy resistance exercise, the specific
hormonal response is dependent in large part on the
five acute training variables.
Acute Response to Resistance Exercise

   Testosterone: responds most when large-muscle-
    mass, multi-joint exercise are performed and when
    high-power exercises are used

   Cortisol: responds much like testosterone but
    exhibits a larger acute response to resistance
    exercise

   Growth hormone: responds like testosterone and
    cortisol but may produce a larger response from the
    use of free weights than machine exercises
Key Point
Long-term hormonal adaptations to training are more
subtle than the acute response to a single session, but
they can provide an important training adaptation.
Overtraining
Overtraining:
   The only way to continue to improve exercise
    performance with training is to progressively
    increase the training stress.

   However, when this concept is carried too far,
    pushing the body beyond its ability to adapt, the
    training may became excessive.
Overtraining:
   Overtraining is an imbalance between exercise and
    recovery in which the athlete’s training program
    execeeds the body’s physiologic and psycologic
    limits and causes fatigue and reduced functional
    capacity.

   This problem results from a short to medium-term
    increase in training volume and/or intensityover the
    athlete’s previously substantial baseline.
Overtraining
   An increase in training volume and/or intensity
    (training load) resulting in performance decrements

   Associated with chronic overwork or long-term
    training stress
Overtraining

     Normal Response to Training




                                                               Potential for Overtraining




 Verhoshansky, Y.V. (1986) Fundamentals of Special Strength Training in Sport
Overtraining
        OVERTRAINING SYNDROME



            Overload


               Fatigue


                Overreaching


                   Overtraining
Overtraining:
   Overload
     necessary    stimulus needed to improve
   Fatigue
     normal   response to training
   Overreaching
     short-termovertraining (less than 4 weeks)
     sometimes planned
 Developement of Overtraining

                                     Physical factors
Emotional factors :
 Demands of competition
 Desire to win
 Fear of failure                   OVERTRAINING
 Unrealistically high goals



           Decline in performance accompained by a loss
           in competitive desire and a loss in enthusiasm
                             for training
Developement of Overtraining
Physical factors

  Too intense                                           Too high
                       Excessive training
 Training load                                       Training volume




          Overcaming the body’s ability of recovering and
                           adapting



                                                Overtraining
Catabolism > Anabolism
                                                 syndrome
Overtraining and the Endocrine System

   Overtraining occurs when training volume and/or
    intensity is excessive and results in prolonged
    decreases in performance

   It has been suggested that monitoring certain
    hormones may permit monitoring of the training
    stresses, thus avoiding the onset of an overtrained
    state
Changes in hormone blood levels
during a period of intensified training
Recovery:
   Recovery from overtraining syndrome is only
    possible with a marked reduction in training
    intensity or complete rest.

   The best way to minimize the risk of overtraining is
    to follow cycling training procedures, alternating
    easy, moderate and hard periods of training.
     Periodization
Overtraining
   Prolonged Recovery
     Recovery  period need in excess of 2-weeks
     Can last up to 1-year
Resistance Exercise:
CR Adaptations
CR Adaptations:
   Regular physical activity can improve
    cardiovascular fitness and may reduce the
    likelihood and debilitating effects of cardiovascular
    disease.

   Weight-training has generally been believed to
    have limited value in modifying risks of
    cardiovascular disease.
CR Adaptations:
   Acute aerobic exercise results in increased
    cardiac output, stroke volume, heart rate,
    oxygen uptake, systolic blood pressure, and
    blood flow to active muscles and a decrease in
    diastolic blood pressure.

   Resistance exercise with low intensity and high
    volume generally results in similar responses,
    some to a lesser degree.
CR Adaptations:
   Aerobic exercise training results in increased
    maximal cardiac output and maximal oxygen
    uptake, slower resting heart rate, increased
    capillarization, improved ventilation efficiency,
    increased oxygen extraction, and OBLA
    occurring at a higher percentage of aerobic
    capacity.
CR Adaptations:
   Acute bouts of high-intensity, low-volume
    resistance exercise result in increased heart
    rate and increased diastolic and systolic blood
    pressure but no change in oxygen uptake, no
    change or a slight increase in cardiac output,
    and no change or a slight decrease in stroke
    volume.

								
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