Muscle Contraction and Exercise

Differentiate Between Contractions Twitch; single contraction of muscle fibers/single threshold stimulus/lab induced Tetanic; caused by a series of stimuli in rapid succession/sustained and steady

Isotonic; produces movement at joint/ muscle changes length/ I to O Walking/ running..lifting a book Isometric; no movement, muscle as a whole does not shorten/ tension within the muscle increases…holding a book in mid air

Exercise Improves muscle tone (muscle firmness/posture) More efficient C/V system (heart muscle) More efficient lung functioning Decreased fatigue

Training Strength vs. Endurance Strength: contraction of muscles against heavy resistance Increases # of myofilamants in each muscle fiber(not the # of muscle fibers) Total mass of muscle increases

Endurance; (aerobic training) Increases a muscle’s ability to sustain exercise Does not usually result in hypertrophy Increases efficiency of oxygen and nutrient delivery