Muscle and joint mechanical properties during plantar flexion were investigated in 13 elderly women (EW) (age range 73-83 years) and 15 elderly men (EM) (age range 74-81 years). Maximal torque, at several angular velocities, was measured to construct torque-velocity relationship. This led to the calculation of an index of maximal shortening velocity (VI_max) at 10% of maximal isometric torque. Two methods were then used to calculate musculotendinous (quick-release movements) and musculoarticular (sinusoidal perturbations) stiffness. In both cases, stiffness was linearly related to torque, and the slope was defined as a stiffness index (SI): SI_MT and SI_MA, respectively. Maximal torques as well as VI_max (p < .05) were lower in EW compared with EM. Furthermore, SI_MT and SI_MA values were higher for EW than for EM (p < .05). These results are interpreted in terms of possible differences in the muscle mass, fiber-type distribution, and tendons. They may also have implications for daily motor behavior.