Adaptations in Motor Unit Behavior in Elderly Adults

Alterations in motor unit behavior associated with aging deteriorate fine or gross motor performance. In human aging, the alterations depend on muscles and the habitual activity of each muscle. This paper will discuss the current knowledge on the adaptations in major aspects of motor unit behavior including recruitment order, mean and maximal discharge rate, synchronized discharges, oscillatory discharges, and discharge variability in elderly adults to identify unresolved problems. By considering studies on disuse in young adults and training in elderly adults, future research directions are proposed to help resolve the problems.