Plantar pressure distribution during gait in athletes with functional instability of the ankle joint: preliminary report.

This study addressed the hypothesis that gait characteristics differ between normal subjects and athletes suffering from functional instability (FI) of the ankle joint. FI of the ankle joint is one of the most common residual disabilities after an acute ankle sprain. However, the influences of the FI of the ankle joint on the gait characteristics are not well understood. Athletes suffering from FI of the ankle joint and healthy control subjects were examined. Pressure, area, and force during gait were measured using a pressure measuring system. These in vivo plantar pressure measurements were performed during free walking. The foot angle and the pronation-supination index were calculated. Those in the FI group were found to exhibit a significantly lower dynamic foot angle and a greater pronation-supination index at the midsupport phase of gait than those in the control group. The results showed increased adduction-supination of the foot at the stance phase of gait in those with FI of the ankle joint.