Extra Credit Flashcards
summation
Process by which the force of individual muscle fiber twitches (contract & relax) combine
twitch
A single contract-relax cycle of a single muscle fiber
recruitment
Number of motor units activated
all or none principle
A muscle fiber exposed to a stimulus of threshold strength or more will contract completely
delayed onset muscle soreness (DOMS)
This soreness increases in intensity for the first 24 hours after activity, peaks from 24-48 hours, and then declines during the next 5-7 days.
ischemia
suggests that exercise - even moderate, atraumatic activities-causes swelling the muscle tissue, which increases tissue pressure.
This increase in tissue pressure is thought to result in local ischemic (reduced blood flow), which causes pain and lead to tonic muscle constriction (spasm).
theories of fatigue
the depletion (or exhaustion) hypothesis and the accumulation hypothesis.
The depletion hypothesis suggests that fatigue results form depletion of certain metabolites, specifically, ATP, CP, and glycogen.
Hence, the muscle fibers are no longer able to produce force.
The accumulation hypothesis suggests that fatigue is caused by the accumulation of certain metabolites that have been shown to impair force generation within muscles, specifically, hydrogen ion, ammonia, and phosphate.
results in the cessation of muscular work or the inability to maintain a given intensity of work
Failure of neuromuscular transmission
results from biochemical and metabolic changes within the contractile elements (myofilaments of the muscle cell)
fatigue
a transient loss of work capacity resulting from preceding work; inability of muscle to contract forcefully after prolonged activity.
Fatigue limits performance in normal conditions and even more so in disease.
Peripheral fatigue
refers to fatigue at a site beyond the central nervous system; this may include sites within the peripheral nervous system or within the skeletal muscle.
