9.7 +8 Chapter Human Structure and Function

4 factors of muscle contraction

Frequency, strength, size, degree of stretch

Frequency of stimulation

Muscle is stimulated more frequently contractions are summed, Higher the frequency the greater the force of contraction

Strength of contraction

More motor units the greater the force 

Size of muscle fibers

Bulkier the muscle fibers and greater the cross-sectional area themore tension it can develop, Resistance exercises cause hypertrophy in muscle cells

Degree of muscle stretch

Muscles and sarcomere stretch, stretch when close to resting length by optimal overlap from thin and thick filaments

3 classifications of muscle fibers

Slow oxidative, fast oxidative, fast glycolytic

Slow oxidative

Slow movement of ATP, Use aerobic pathways, best for endurance

Fast oxidative

Fast movement of ATP, use aerobic pathways

Fast glycolytic

Fast movement of ATP, use anaerobic pathways, uses the least oxygen

Aerobic exercise

Changes in slow oxidative fibers, endurance exercise, increases fatigue resistance

Changes to skeletal muscle in aerobic exercise

More oxygen, more myoglobin, more capillaries, more mitochondria

Resistance exersice

changes in fast glycolytic fibers, High intensity exercise, causes muscle hypertrophy,

Changes to skeletal muscle in resistance exercise

Increase in glycogen, increase in force production, increase in actin, increase in myosin

Overload principle

Placing a greater load on a muscle than it can handle, resistance exercise , increases strength