Muscular Strength & Endurance Fitness Concepts PEAC 1621 Kirk Evanson

Muscle Physiology Muscle Muscle Composition and Organization Composition and Organization Muscle fiber (muscle cell)- composed of myofibrils Muscle fiber (muscle cell)- composed of myofibrils Myofibrils → muscle fibers → fascicles → muscles Myofibrils → muscle fibers → fascicles → muscles Muscle fiber types Muscle fiber types Slow-twitch (aerobic)- relatively fatigue resistant, but they don’t contract as rapidly or strongly as fast-twitch fibers. Slow-twitch (aerobic)- relatively fatigue resistant, but they don’t contract as rapidly or strongly as fast-twitch fibers. Fast-twitch (aerobic or anaerobic)- contracts more rapidly and forcefully than slow-twitch fibers but fatigue more quickly. Fast-twitch (aerobic or anaerobic)- contracts more rapidly and forcefully than slow-twitch fibers but fatigue more quickly.

Muscle Physiology Muscle Muscle Most muscles contain a mixture of slow-twitch and fast-twitch fibers Most muscles contain a mixture of slow-twitch and fast-twitch fibers Endurance activities (e.g. jogging, swimming) primarily utilize slow-twitch while power activities (e.g. weight lifting) utilize fast-twitch Endurance activities (e.g. jogging, swimming) primarily utilize slow-twitch while power activities (e.g. weight lifting) utilize fast-twitch Motor unit- the motor nerve and the muscle fibers that are innervated by that nerve Motor unit- the motor nerve and the muscle fibers that are innervated by that nerve

Benefits of Muscular Strength and Endurance Injury Prevention Injury Prevention Good muscle strength in areas such as the abdomen, hips, lower back, and legs can support the back in proper alignment and help prevent low- back pain Good muscle strength in areas such as the abdomen, hips, lower back, and legs can support the back in proper alignment and help prevent low- back pain Training also improves the strength of tendons, ligament, and cartilage cells, which decreases the risk for injury Training also improves the strength of tendons, ligament, and cartilage cells, which decreases the risk for injury

Benefits of Muscular Strength and Endurance Improved Body Composition Improved Body Composition Strength training improves body composition by increasing muscle mass Strength training improves body composition by increasing muscle mass Increases in muscle mass increase basal metabolic rate. Increases in muscle mass increase basal metabolic rate. BMR can increase up to 15% BMR can increase up to 15% The body requires more calories, therefore there is less fat deposition The body requires more calories, therefore there is less fat deposition

Benefits of Muscular Strength and Endurance Improved Muscle and Bone Health with Aging Improved Muscle and Bone Health with Aging Strength training prevents muscle and nerve degeneration commonly associated with aging Strength training prevents muscle and nerve degeneration commonly associated with aging Also decreases the risk of hip fracture and other life- threatening injuries Also decreases the risk of hip fracture and other life- threatening injuries Decreases the progressive loss of muscle tone with age (sarcopenia) Decreases the progressive loss of muscle tone with age (sarcopenia) By age 75, 25% of men and 75% of women will be unable to lift 10 lbs. By age 75, 25% of men and 75% of women will be unable to lift 10 lbs. Weight training can mitigate these changes Weight training can mitigate these changes

Benefits of Muscular Strength and Endurance Prevention and Management of Chronic Disease Prevention and Management of Chronic Disease Strength training improves glucose metabolism Strength training improves glucose metabolism Modifies the risk factors for cardiovascular disease Modifies the risk factors for cardiovascular disease Decreases diastolic blood pressure Decreases diastolic blood pressure Positive alterations in cholesterol Positive alterations in cholesterol Increases in HDL, decreases in LDL Increases in HDL, decreases in LDL Strength training improves bone mineral density Strength training improves bone mineral density Beneficial in the prevention of osteoporosis and associated bone fractures Beneficial in the prevention of osteoporosis and associated bone fractures

Types of Exercise Static (isometric) Exercise Static (isometric) Exercise Involves a muscle contraction without a change in the length of the muscle or the angle in the joit on which the muscle acts. Involves a muscle contraction without a change in the length of the muscle or the angle in the joit on which the muscle acts. Common for early physical therapy Common for early physical therapy Do not build muscle throughout the range of motion Do not build muscle throughout the range of motion Dynamic (isotonic) Exercise Dynamic (isotonic) Exercise Involves a muscle contraction with a change in the length of the muscle Involves a muscle contraction with a change in the length of the muscle

Types of Exercise Dynamic Exercise (cont.) Dynamic Exercise (cont.) Constant resistance exercise Constant resistance exercise Fixed weight- easier at certain joint angles due to mechanical advantages based on muscle insertion points and length Fixed weight- easier at certain joint angles due to mechanical advantages based on muscle insertion points and length Variable resistance- resistance is varied throughout the movement to maintain intensity throughout all joint angles Variable resistance- resistance is varied throughout the movement to maintain intensity throughout all joint angles

Types of Exercise Dynamic Exercise (cont.) Dynamic Exercise (cont.) Eccentric- involves placing a load on a muscle as it lengthens Eccentric- involves placing a load on a muscle as it lengthens Plyometrics- the sudden eccentric loading and stretching of muscles followed by a forceful concentric contraction Plyometrics- the sudden eccentric loading and stretching of muscles followed by a forceful concentric contraction

Types of Exercise Dynamic Exercise (cont.) Dynamic Exercise (cont.) Isokinetic- the resistance can be moved at a fixed speed. Measurements can be made for multiple muscle groups in addition to group comparisons (quadriceps/hamstring ratio) Isokinetic- the resistance can be moved at a fixed speed. Measurements can be made for multiple muscle groups in addition to group comparisons (quadriceps/hamstring ratio) uFjyHFfgLg/s320/JustinIsokineticMach1.JPG

Exercise Equipment Free vs. Machine weights Free vs. Machine weights Free weights Free weights Pros Pros More muscles needed for the movement More muscles needed for the movement Improvements made in multiple areas Improvements made in multiple areas Requires more calories than machine weights Requires more calories than machine weights Cons Cons Movements are more complex and require more strength- the risk of injury increases Movements are more complex and require more strength- the risk of injury increases Spotters may be needed Spotters may be needed

Exercise Equipment Free vs. Machine weights Free vs. Machine weights Machine weights Machine weights Pros Pros Reasonably easy to perform Reasonably easy to perform Many safety mechanisms in place to decrease (but not eliminate) the risk of injury Many safety mechanisms in place to decrease (but not eliminate) the risk of injury Cons Cons The intensity of the movement has a limit- can only recruit so many muscles to do a controlled movement The intensity of the movement has a limit- can only recruit so many muscles to do a controlled movement It can be difficult to find the ‘perfect’ machine to work the desired target area It can be difficult to find the ‘perfect’ machine to work the desired target area

FITT Principle Exercise frequency Exercise frequency 2-3 days/week 2-3 days/week 48 hours of rest needed to allow for adequate recovery 48 hours of rest needed to allow for adequate recovery Exercise intensity and volume Exercise intensity and volume Repetitions and Sets Repetitions and Sets Low repetitions- maximal effort- increase in strength Low repetitions- maximal effort- increase in strength High repetitions- medium effort- increase in muscular endurance High repetitions- medium effort- increase in muscular endurance

FITT Principle Exercise intensity and volume (cont.) Exercise intensity and volume (cont.) Repetitions and Sets Repetitions and Sets 3-5 sets 3-5 sets Sets can be determined based off of the intensity of the set Sets can be determined based off of the intensity of the set Type or mode of exercise Type or mode of exercise Variety is the spice of life- work multiple muscle groups Variety is the spice of life- work multiple muscle groups

Exercise Training Specificity Specificity The body will adapt to stress The body will adapt to stress A leg press will not appreciably improve lower body muscle endurance, however jogging will A leg press will not appreciably improve lower body muscle endurance, however jogging will Exercises should be selected based off of individual exercise goals Exercises should be selected based off of individual exercise goals