Background: Because many of our movements of daily living are multi-joint movements and lower limb performance decreases with aging, it is important to understand the influence of aging on muscle functions of lower limb multi-joint movements. Objective: To investigate aging-related differences in the maximum force, unloaded velocity and power of muscles that control leg multi-joint movements. Methods: 285 recreationally active men (n = 142) and women (n = 143) aged between 18 and 82 years volunteered for the study. Lower limb muscle function was measured with a servo-controlled dynamometer and the maximum isometric force (Fmax), unloaded velocity (Vmax) and power (Pmax) were determined by the force-velocity and force-power relations. Results: With increasing age, Fmax/body mass significantly declines in both men (r = –0.400, p 0.05) or women (r = –0.040, p > 0.05). Pmax significantly declines with age in both men (r = –0.370, p < 0.001) and women (r = –0.446, p < 0.001). Conclusions: Aging does not have effects on the shortening velocity, although it causes a decrease in maximum force and power of leg multi-joint movements. This finding suggests that decreases in muscle force-generating capacity and power may primarily lead to the loss of mobility and a reduced capability of accelerating and decelerating the body mass during the movements in elderly individuals.