The amount and three-dimensional distribution of the ground reaction force during running are related to lower limb injuries. The shoe insole is effective in modulating the components of ground reaction forces. The aim of this study was to evaluate the effect of using Arch support insole when running on the values of ground reaction force, impulse, and loading rate during running in people with an ankle sprain. Ten healthy men and 10 soccer player with ankle sprain participated in this study. Using a force plate with a sampling frequency of 1000 Hz, the components of the ground reaction force during running in two conditions with and without insoles were measured. Then, the variables of the peak of the ground reaction forces, the time of reaching the peak of the ground reaction forces, the impulse, and the loading rate were extracted. Repeated measurement analysis of variance was used for intragroup comparison and a Multivariate ANOVA test was used for intergroup comparison with a significance level of 0.05 for statistical analysis. The experimental group had a greater vertical ground reaction force than that control group (P = 0.01). Using the insole had no effect on the value of the ground reaction forces (P> 0.05). Using insole increases the time to reach the peak of the vertical ground reaction force at the moment of heel contact with the ground (P = 0.01). The insole decreased the loading rate of the experimental group (P = 0.023). It seems that the insole used in the present study can possibly reduce the risk of lower limb injury due to the reduction of the values of the vertical loading rate and the vertical impulse.
