The influence of ageing on the force-velocity-power characteristics of human elbow flexor muscles.

The purpose of this study was to quantify the effects of ageing on the maximal power (P(max)) of the elbow flexor muscles and to determine the impact of velocity on the loss of power in older people. Sixteen elderly subjects (7 men and 9 women, age range 61-78 years) and 17 young subjects (11 men and 6 women, age range 18-27 years) participated in this study. Maximal elbow flexions were performed against increasing inertia. The maximal force (F(max)), maximal shortening velocity (V(max)), P(max), dynamic constants (a, b and a/F(max)), optimal force (F(opt)), optimal velocity (V(opt)) and V(opt)/V(max) were determined from Hill's equation. Myoelectrical activity (EMG) of the biceps and triceps muscles was quantified as an root mean square (RMS) value. F(max), V(max), P(max), F(opt), and V(opt) were significantly lower in elderly than in young subjects (28, 31, 45, 24 and 28% lower, respectively; p<0.05), whereas a/F(max) and V(opt)/V(max) were not different between the two age groups. In women, the greater decrease in P(max) appears to be more dependent on V(opt) than F(opt). In addition, V(max) decreased with age in women but not in men. The absence of significant differences between age groups in normalised RMS values indicates that P(max) and V(max) loss with increasing age could result more from changes in the properties of contractile element than from changes in muscular activity.