Immediate effect of insoles on the components of reaction forces during gait in people with ankle instability

The amount and distribution of ground reaction forces(GRF) and loading rates during gait are related to the injuries of the lower limb joints. One of the methods to change GRF and loading rates is using insoles. The aim of this study was to analyze the effect of insoles on GRF and loading rates during gait in individuals with ankle instability. Eleven healthy male soccer players and eleven patients with functional ankle instability participated in this study. Using force plates, the components of GRF were measured during gait under the two conditions of with and without insoles. Maximum GRF and their related peak time, loading rate were recorded.. ANOVA and MANOVA was used to analyze the data (α = 0.05). Compared to the group without insoles, in the other group, wearing an insole caused an increase in the initial peak of the vertical reaction force (p = 0.01) at the moment of the heel’s contact with the ground (p <0.05). There was no significant difference in the loading rates of the two groups. In the mid stance phase, the maximum vertical GRF of the group wearing insole was significantly lower than that of the control group. The results showed that the insole did not modify the GRF it did not reduce loading rates. Therefore, therapists should pay particular attention to reducing these forces by modifying motor strategies and designing appropriate shoes and exercise programs for strengthening muscles. Keywords: ground reaction forces, loading rates, ankle instability, insoles, gait