We investigated the effects of strength training on the force-velocity relationship and muscle power in aged men. Fifteen male volunteers, ranging in age from 65 to 78 years, were divided into three groups. The LG group (n=6) performed two sets of maximal repetitions at a relatively low intensity load of 15-20 RM and the HG group (n=5) performed three sets of maximal repetitions using a relatively high intensity load of 8-10 RM. The control subjects (CG group, n=4) performed no special exercises. The training was performed by elbow flexion using a dumbbell-curl exercise 3 days a week for 10 weeks. Muscle cross-sectional area was estimated by measuring muscle thickness with an ultrasonic apparatus. Our results showed that the force-velocity curves in the two training groups were shifted in a direction away from the origin, though Vmax did not change significantly in either of the groups. In the HG group, significant increases were observed in maximal isometric strength and velocity under 10% Fmax load. Despite the significant increase in Fmax, the HG group did not show a significant change in muscle cross-sectional area. The maximal power was increased significantly only in the HG group. These results suggest that high-intensity training may be necessary for increasing muscle strength and power in aged people, and that the effects of training in older adults may be more functional than morphological.