Human ageing: impact on muscle force and power

Fig. 19.4 summarizes the factors that contribute to the loss of power during ageing. The main factors are loss of muscle mass, a fast-to-slow transition in areal fiber type composition, an increase in connective tissue and altered neural drive. In addition, the quality of the remaining tissue is affected as reflected by a reduced specific tension and shortening velocity seen in single muscle fibers. Part of these ageing-related changes are attributable to lower physical activity levels in old age and can be reversed by exercise, but there also appears to be an ageing process per se that is irreversible