The purpose of the study was to compare passive joint stiffness in ankles of young and elderly men (21–39, and 64–87 years, respectively). A torque motor system was used to record angular displacement and resistive torque during a slow 6 degree/second ankle rotation from 10 degrees of plantarflexion to 10 degrees of dorsiflexion (DF). Passive torque (Nm) and passive elastic stiffness (Nm/degree) were measured at neutral, 5 and 10 degrees of DF. Passive torque increased nonlinearly as the ankle was rotated into DF. The elderly men had significantly lower passive torque values (p < .05), but there was no age-related difference in passive elastic stiffness. Variability of the two measures was greater in the older group. We concluded that within the range of motion tested, there was no evidence of increased stiffness in the elderly ankle joints.
