The present study aimed to investigate the characteristics of force, velocity and power relations of elbow flexion in elderly people. The subjects were 22 elderly men (aged 61-77 y) and 19 college male students (ages 20-24 y). Using a modified Wilkie's apparatus, the force, velocity and resultant power output by the elbow flexor muscles were measured, and the force-velocity relations were calculated according to Hill's equation : (F + a) (V + b)=(Fmax + a) b. Cross-sectional area (CSA-ante) of the upper arm was estimated from the square of the muscle thickness measured by an ultrasonic apparatus. The force-velocity curve for the elderly group (G-aged) was found to be less concave (larger a/Fmax) than that of the college students (G-young). The maximal power values, which appeared at an Fmax under about 34% in both age groups, were 107.8 W in G-aged and 155.0 W in G-young. There were significant differences (G-aged < G-young) in Pmax as well as in Fmax and Vmax. The ratios of Fmax/CSA-ante, Pmax/CSA-ante and Vmax/upper arm length were also significantly lower in G-aged than in G-young. The half time to reach Fmax (1/2RFD) was significantly longer in G-aged (117.4 ms) than in G-young (93.1 ms). Compared with G-young, G-aged showed a greater reduction in Pmax (69.3%) than in Fmax (76.0%) and Vmax (83.5%). In CSA-ante, however, no significant difference was observed between the two age groups, suggesting a considerable effect of neuromuscular function. From these results, it was suggested that the ability to develop muscular power may be reduced more functionally than morphologically with increasing age.