Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition 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 Strength-testing considerations –Standardize pretesting instructions –Uniformity of warm-up –Adequate practice –Standardize testing protocol Body position Joint angles Reps Scoring criteria –Score relative to body size Measurement of Muscle Strength

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

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Types of Muscle Contractions

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Resistance Training for Children Closely supervised Only concentric contractions High reps, low resistance Increase weight gradually (small increments) Focus on technique Emphasize spotting and safety Avoid maximal lifts

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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: –Focuses on benefits in health and disease –Single sets –8- to 15-RM –At least 2 days per week

Copyright © 2007 Lippincott Williams & Wilkins.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.

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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.

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.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 –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.

Copyright © 2007 Lippincott Williams & Wilkins.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

Copyright © 2007 Lippincott Williams & Wilkins.McArdle, Katch, and Katch: Exercise Physiology: Energy, Nutrition, and Human Performance, Sixth Edition Muscle Cell Remodeling Some fiber-type transformation may occur. Myostatin may play a role. Indications of new fiber production Training induces changes in muscle fiber- type 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 stair- climbing 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