motor units

one single nerve impulse elicits

a single muscle twitch contraction in all muscle fibers it innervates

frequency of stimulation is

number of impulses per second

frequency of stimulation

governs total tension produced by a single muscle fiber when stimulated

total tension in whole skeletal muscle organ

depends on number of individual muscle fibers contracting at same time

contraction control: small MU

many small motor units control small, precise movement

many small motor units

10-20 muscle fibers per motor unit

contraction control: large MU

fewer larger motor units control large powerful movements

larger motor units

up to 3k muscle fibers per motor unit

contraction strength

size of a skeletals muscle motor unit

contraction strength is

number of motor units activated