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PowerPoint Presentation Muscular Strength Resistance

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PowerPoint Presentation Muscular Strength Resistance

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									   Muscular Strength
•Making muscles stronger
   Why is this important?
•What do you need to know?
Objectives of Strength Training
 •   General fitness
 •   Body building
 •   Bone fitness
 •   Physical therapy and rehabilitation
 •   Sport-specific applications
 •   Muscle physiology
Anterior view
Posterior view
      Muscle Physiology
• Muscles consist of many muscle fibers
  (cells) connected in bundles
• Muscle fibers are made up of myofibrils
• Strength training increases the number
  of myofibrils and the size of muscle
  fibers = hypertrophy
• Inactivity reverses the process = atrophy
Skeletal Muscle Tissue
             Muscle Fibers
• Slow-twitch fibers
  – Fatigue resistant
  – Don’t contract as rapidly and forcefully as fast-
    twitch fibers
  – Rely primarily on oxidative (aerobic) energy
• Fast-twitch fibers
  – Contract rapidly and forcefully
  – Fatigue more quickly than slow-twitch fibers
  – Rely more on nonoxidative (anaerobic) energy
               Motor Units
Motor units (nerves connected to muscle fibers) are
 recruited to exert force
Physiological Effects of Strength Training

 – Increased muscle mass and size of muscle fibers
 – Increased utilization and coordination of motor
 – Increased strength of tendons, ligaments, and
 – Increased storage of fuel in and blood supply to
 – Improvements in blood fat levels and biochemical
    Benefits of Muscular Strength
           and Endurance
 Improved performance of physical activities
 Injury prevention
 Improved body composition
 Enhanced self-image and quality of life
 Improved muscle and bone health with aging
 Prevention, management of chronic disease
Factors that Modify Strength
   Assessing Muscular Strength
          and Endurance
• Muscular strength assessed by
  determining repetition maximum (1 RM),
  the maximum resistance that can be lifted
• Muscular endurance assessed by counting
  the maximum number of repetitions of a
  muscular contraction
     Types of Strength Training
• Static (isometric) exercise = muscle contraction
  without a change in the length of the muscle
• Dynamic (isotonic) exercise = muscle
  contraction with a change in the length of the
  – Concentric contraction = muscle applies force as it
  – Eccentric contraction = muscle applies force as it
              Muscle Actions


     Types of Dynamic Exercise
• Constant resistance = constant load throughout a joint’s
  range of motion
• Variable resistance = changing load to provide maximal
  resistance throughout a joint’s range of motion
• Eccentric loading = placing load on a muscle as it
• Plyometrics = sudden eccentric loading and stretching
  followed by a concentric contraction
• Speed loading = moving a load as rapidly as possible
• Isokinetic exercise = exerting force at a constant speed
  against an equal force
Plyometric Training
 Creating a Successful Weight Training Program

Choosing equipment: Weight machines versus free
  – Resistance is provided by both types
  – Exercise machines
     • Safer, convenient, and easy to use
  – Free weights
     • Require more care, balance, and coordination
     • Strength transfers to daily activities
Applying the FITT Principle
•   Frequency = days per week
•   Intensity = amount of resistance
•   Time = number of repetitions and sets
•   Type = strength training exercises for all
             major muscle groups
    Frequency of Exercise

• American College of Sports
  Medicine recommends 2-3 days
  per week
  – Allow 1 full day of rest between
• 8 minutes in the morning- daily
Intensity of Exercise: Amount of Resistance

• Choose resistance based on your current fitness level
     and goals
• To build strength
   – Lift heavy weights (80% of 1 RM)
   – Perform a low number of repetitions
• To build endurance
   – Lift lighter weights (40-60% of 1 RM)
   – Perform a high number of repetitions
• For a general fitness program
   – Lift moderate weights (70% of 1 RM)
   – Moderate number of repetitions
Time of Exercise: Repetitions & Sets
• To build strength and endurance, do enough
  repetitions to fatigue the muscles
• The heavier the weight, the fewer the
  repetitions (1-5) to fatigue = a program to
  build strength
• The lighter the weight, the higher the number
  of repetitions (15-20) to fatigue = a program to
  build endurance
• To build both strength and endurance, try to do
  8-12 repetitions of most exercises
Strength versus Endurance
 Time of Exercise: Repetitions and Sets

• Set = a group of repetitions followed by a rest
• For general fitness, 1 set of each exercise is
• Doing more than one set will increase strength
• Rest between sets
             Type of Exercise
• For a general fitness program:
  – 8–10 different exercises
  – Work all major muscle groups
  – Balance between agonist and antagonist
    muscle groups
  – Do exercises for large-muscle groups and
    multiple joints before exercises for small-
    muscle groups or single joints
Strength Testing
 • Standardization
 • Warm-Up
 • Practice
 • Muscle Angle
Testing 1-RM Bench Press - machine
Load:Repetition Relationships
    120       One can perform high
              reps with light loads, and

              few reps with near max

N                            Strength Training Zone

          0    20   40       60              80       100

                     Maximum Load
    Which System is Best?

• Specificity rules [specific
 adaptations to imposed demands
 - SAID]

• Overload is the key
    Comparative Training
 Responses in Men and Women
•Muscular hypertrophy occurs to a
much greater extent in men
 –Represents the largest sex difference in
 response to resistance training
 –Both sexes experience similar
 percentage strength improvements
          Creating a Successful
       Weight Training Program (cont’d)
• Making progress
• More advanced strength training programs
• Weight training safety
  –   using proper lifting techniques
  –   using spotters and collars with free weights
  –   use common sense when exercising on weight machines
  –   be alert for injuries
  Setting Up Your Program           (cont)

• Avoid max lifts initially
• Use 12 to 15 reps initially
• Increase weight after 2 weeks
  – Use 6 – 8 reps
  – Progress gradually
• Work larger muscle groups first
Gains in strength may be seen
after 1 to 2 weeks of training

Training as few as 1 to 2 times
per week may be adequate to
maintain strength training gains
 Combining Strength & Endurance Training

• Resistance training plus aerobic
  training equals less strength
• Incorporate a break between workouts
• Health benefits of both types of
  training may be obtained by training
  for both strength & endurance
    Muscle Soreness [DOMS]
•   Cell damage hypothesis
•   Spasm hypothesis
•   Tear hypothesis
•   Excess metabolite hypothesis
•   Connective tissue damage
     Sex Differences in Strength
     • Upper Body - women 50% weaker

     • Lower Body - women 30% weaker

Human muscle can generate 3 to 8 kg force per
cm of muscle cross sectional area
On a relative basis women are just as strong as
men - and in the lower body, they are stronger!
  Warm Up and Cool Down
• Warm up prior to each weight training
  session with a general warm-up and a
  warm-up for the exercises you will
• Cool down after weight training, relax
  for 5-10 minutes, lower your heart rate
      Weight Training Safety

• Use proper lifting

• Use spotters and
  collars with free

• Be alert for injuries
  A Caution About Supplements/ Drugs

• Supplements taken to increase muscle growth;
  – Anabolic steroids
  – Growth hormone
  – Androstenedione
  – Insulin and insulin-like growth factor (IGF-1)
 Anabolic Steroids- ACSM Position
1. With adequate diet and training-
   increases in body weight occur often in
   lean tissue.
2. No increase in aerobic power or capacity
   for muscular exercise.
3. Associated with many adverse effects.
4. Use by athletes is contrary to rules and
   ethical principles of competition.
Side Effects of Anabolic Steroids
• Liver damage and tumors
• Reduced HDL
• High blood pressure, heart disease, cancer
• Depressed immune function
• Psychological disturbances
• Depressed sperm and testosterone production
  breast development in males
• Masculinization in women and children
• Premature closure of bone growth centers
      Anabolic Steroids
• Drug with a considerable following
  –Its becoming increasingly popular
   with more than just strength

• Effectiveness
  –Dosage is an important factor
  –Training volume accompanying
       Anabolic Steroids
• Structure and action
 –Sterol structure similar to testosterone
 –Promotes protein synthesis
• Stacking
 –Combining multiple steroid
  preparations in oral & injectable form
• Pyramiding
 –Progressively increasing the dosage
Examples of oral and injectable anabolic steroids
  Generic Name    Commerical           Form            Retail $       Black
                    Name                                             Market $
Oxymetholone     Anadrol-50       Oral: 50 mg        $115/100 tabs   $200-500
Oxandrolone      Oxandrin         Oral; 2.5 mg       $420/100 tabs   $600-1600
Stanazolol       Winstrol V       Oral; 2 mg         $100/100 tabs   $200-500
Nandrolone       Durabolin        Inject; 25 mg/ml   $275/ml vial    $200-500
Deconate         Deca-Durabolin   Inject; 25 mg/ml   $12/2 ml vial   $400-750
Androlone-D200   Neo-durabolic    Inject; 50 mg/ml   $12/2 ml vial   $450-750
Life-shortening Effects of Exogenous Steroids Use in Mice
Changes from
baseline in average
FFM, muscle, fat,
and strength over
10-wks of
        Growth Hormone
• Genetic engineering comes to sports
  – Human growth hormone
    • Produced in the Pituitary gland
    • Stimulates bone & cartilage growth
    • Enhances fatty acid oxidation
    • Reduces glucose & amino acid breakdown
  – Excess GH may result in:
    • Gigantism
    • Acromegaly
  – No unanimity among researchers
  DHEA: A Worrisome Trend
• DHEA- Dehydroepiandersterone
  – Steroid hormone produced by the adrenal glands
• Claims for DHEA
    •   Testosterone booster
    •   Bolsters immune system
    •   Preserves youth
    •   Decreases fatigue & joint pain
    •   Slows aging
    •   Invigorates sex life
  – An unregulated compound with uncertain safety
• Claims:
  – Stimulates production of endogenous
  – Enables one to train harder
  – Increases muscle mass
  – Aids healing/recovery process

• Research shows no effect of
  supplementation on basal serum
  testosterone or any training response in
  terms of muscle size & strength
 A Caution About Supplements/Drugs

• Supplements taken to speed recovery from
   – Creatine monohydrate
• Substances taken to increase training intensity
  and overcome fatigue
   – Amphetamines
   – Caffeine
• Supplement form - creatine monohydrate
  – Important component of high-energy
  – Documented benefits in humans
    • Improved muscular strength and power
    • Enables heavier lifting for greater overload
  – Creatine loading
    • 20 –25 g/day
  – Some research shows no benefit
A Caution About Supplements/Drugs

• Substances taken to increase endurance
  – Erythropoietin

• Substances taken to aid weight control
  – Fat blockers
  – Stimulants
  – Diuretics

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