Transcript No Slide Title

Chapter 22
Muscular Strength: Training Muscles
to Become Stronger
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Measurement of Muscle Strength
• Cable tensiometry
• Dynamometry
– One-repetition maximum (1-RM)
• Computer-assisted, electromechanical, and
isokinetic methods
– Isokinetic dynamometer
• Resistance-training equipment categories
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Measurement of Muscle Strength
• Strength-testing considerations
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Standardize pretesting instructions
Uniformity of warm-up
Adequate practice
Standardize testing protocol
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Body position
Joint angles
Reps
Scoring criteria
– Score relative to body size
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Learning Affects Strength Measurements
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Gender Differences in Muscle
Strength
• Strength related to muscle cross-sectional
area
– Specific tension is similar in males and females
• Absolute muscle strength
– Males score
• 30% higher on lower-body lifts
• 50% higher on upper-body lifts
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Gender Differences
in Muscle Strength
• Relative muscle strength
– Allometric scaling
– Is scaling fair?
• Controversy exists
– Strength and allometric scaling using body
mass
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Training Muscles to Become
Stronger
• Muscle strength increases when trained
close to capacity.
• Strength training systems
– Progressive resistance training
– Isokinetic training
– Isometric training
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Types of Muscle Contractions
• Dynamic muscle action forms
– Concentric action
• Muscle shortens
– Eccentric action
• Muscle lengthens
– Isometric action
• No net change in muscle length
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Types of Muscle Contractions
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Resistance Training for Children
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Closely supervised
Only concentric contractions
High reps, low resistance
Increase weight gradually (small increments)
Focus on technique
Emphasize spotting and safety
Avoid maximal lifts
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Resistance Training
• Progressive resistance exercise
recommendations
– Use 3-RM to 12-RM
– Use 1-RM one time per week, weeks 2 – 6
– One set is effective if 10-RM is used.
• Produce most of the health benefits
• Increase compliance
• 2 – 3 days per week is most effective
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Resistance Training
• Progressive resistance exercise
– Variations on PRE
– Periodization
• Preparation phase
• First transition phase
• Competition phase
• Second transition phase (active recovery)
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Resistance Training Guidelines
for Sedentary Adults, the Elderly,
and Cardiac Patients
• Benefits in health and disease:
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Focuses on benefits in health and disease
Single sets
8- to 15-RM
At least 2 days per week
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Combining Strength and
Endurance Training
• Resistance training plus aerobic training
equals less strength improvement.
• Incorporate a break between workouts
• Health benefits of both types of training may
be obtained by training for both strength and
endurance.
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Isometric Strength Training
• Isometric exercise limitations
– Strengthens muscle at a specific point in ROM
– Time consuming
• Isometric exercise benefits
– Useful for testing
– Helpful in rehabilitation
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Static Versus Dynamic Methods
• Specificity of the training response
– Practical implications
• Train for desired goals
• Mimic sport performance
• Generalize lifting for health benefits
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Isokinetic Resistance Training
• Accommodating-resistance exercise
– Isokinetics versus standard weight lifting
• Provides variable resistance throughout ROM
• Avoids limitations of sticking point
– Fast- versus slow-speed isokinetic training
• Faster speeds result in increased size of type II fibers.
• More increases in power are seen in fast and slow
movements when fast training is used.
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Plyometric Training
• Uses explosive jumps to mobilize the
stretch-recoil properties of muscle
– Stretch-shortening cycle
• Ballistic resistance training
– Allows athlete to develop greater power at end
of movement
– Simulates sports performance more closely then
regular lifting
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Structural and Functional
Adaptations to Resistance
Training
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Electromyography during
Ballistic Muscle Actions
• EMG aids study of neuromuscular
physiology.
– Triphasic pattern
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Factors that Modify the Expression
of Human Strength
• Psychologic–neural factors include
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More efficient neural recruitment patterns
Increased CNS activation
Improved motor unit coordination
Lowered neural inhibitory reflexes
Inhibition of GTO
• Psychologic–neural factors account for
most initial strength gains.
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Factors Modifying Strength
• Muscular changes include increases in
– Muscle fiber size = hypertrophy
– Enzymes phosphofructokinase, creatine phosphokinase,
and myokinase
– Resting levels of ATP and PCr
– Strength of tendons and ligaments
– Bone mineral content
• Muscular changes include decreases in
– Body fat
– Mitochondria volume and density
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McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Muscle Cell Remodeling
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Some fiber-type transformation may occur.
Myostatin may play a role.
Indications of new fiber production
Training induces changes in muscle fibertype composition.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Benefits Regardless of Age
• Both men and women respond to strength
training regardless of age.
• Elderly also improve gait velocity and stairclimbing speed.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Comparative Training Responses
in Men and Women
• Muscular hypertrophy occurs to a much
greater extent in men.
– Represents the largest gender difference in
response to resistance training
• Muscle strength may relate to bone density.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Detraining
• Loss in strength may be seen after 1 to 2
weeks of cessation.
• Training as few as 1 to 2 times per week
may be adequate to maintain strength
training gains.
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Circuit Resistance Training
• Specificity of aerobic improvement
• Energy cost of different methods
• Specificity of hypertrophic response
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Muscle Soreness and Stiffness
• Delayed-onset muscle soreness (DOMS)
• Eccentric actions produce muscle soreness
• Cell damage
– Altered sarcoplasmic reticulum
– Current DOMS model
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition
Copyright © 2007 Lippincott Williams & Wilkins.
McArdle, Katch, and Katch: Exercise Physiology: Energy,
Nutrition, and Human Performance, Sixth Edition