چکیده (انگلیسی):

Natural adult aging is associated with many functional impairments of the human neuromuscular system. One of the more observable alterations
is the loss of contractile muscle mass, termed sarcopenia. The loss of muscle mass occurs primarily due to a progressive loss of viable
motor units, and accompanying atrophy of remaining muscle fibers. Not only does the loss of muscle mass contribute to impaired function in old
age, but alterations in fiber type and myosin heavy chain isoform expression also contribute to weaker, slower, and less powerful contracting
muscles. This review will focus on motor unit loss associated with natural adult aging, age-related fatigability, and the age-related differences in
strength across contractile muscle actions.