ABSTRACT
Increasing physical frailty is widely accepted as an inevitable concomitant of old age. Physical frailty describes the summation of the effects of muscle atrophy, declining muscle strength and power, fatigue, and injury (Faulkner et al., 1990). Little is known about specific age-associated changes in either the morphological or functional properties of the respiratory muscles. In spite of the lack of data, a reasonable assumption is that the respiratory muscles display deficits similar to those observed for other skeletal muscles. This chapter will address each of the components of physical frailty and the changes associated with aging. Although most of the data on changes in skeletal muscles with aging are obtained from the upper and lower limb muscles of humans and rodents, data on the respiratory muscles will be presented when available. The implications for the respiratory muscles of the age-related changes observed in limb and trunk skeletal muscles will be discussed.
