Ankle sprain is one of the common injuries among athletes and the general public. It seems that limiting the range of motion of ankle inversion can have positive effects on reducing the recurrence rate of ankle sprains. Therefore, the aim of this research is to use medical insoles to prevent excessive ankle movements. 10 soccer players with ankle sprains participated in this research. Kinematic data were collected using a motion recording system including four Vicon cameras and light-reflecting markers with a sampling rate of 100 Hz in two conditions running with and without insoles. Then the peak range of motion of inversion/eversion, dorsiflexion/plantarflexion, abduction/adduction in the ankle and flexion movements, internal/external rotation, abduction/adduction in the knee and flexion/extension movements, internal/external rotation and abduction/adduction in the hip joint in two conditions, with and without medical insoles was evaluated. Repeated measurement analysis of variance was used for intragroup comparison with a significance level (P˂0.05) for statistical analysis. The results of this research showed that medical insoles reduce ankle dorsiflexion (p=0.036, d=1.14), inversion (p=0.003, d=1.44) and abduction (p=0.007: d=1.6). Also, the use of insoles decreased the internal rotation of the knee (p=0.04, d=0.61). Therefore, the use of insoles reduces the kinematic risk factors of ankle sprain and helps the stability of the ankle joint during running. As a result, the use of medical insoles can be suggested as a suitable therapeutic intervention to prevent ankle sprains.
