Effect of long term use of arch support foot orthoses on walking ground reaction force asymmetry index in children with flexible flat feet: A cohort study

Background: Foot orthoses are often used to correct altered gait patterns. However, effect of long term use of arch support foot orthoses on walking mechanics is not well understood. The aim of this study was to evaluate the effects of long term use of arch support foot orthoses on the asymmetry indices of ground reaction forces during stance phase of walking in male children with flexible flat feet.

Methods: Fifteen male volunteered children (with their parents’ permission) with flexible flat feet were evaluated. Walking ground reaction forces and kinematic data before and after four months use of foot orthoses were recorded by force plate and Vicon motion system, respectively. Then, the asymmetry indices of ground reaction force components were calculated.

Results: The results show that asymmetry index of the medio-lateral component of ground reaction force in loading response and push off phases during pre-test were higher than 4% (normal value). Also asymmetry index of its time to peak during the mid-stance phase in the pre-test were higher than normal value. Moreover, findings did not show any significant differences in asymmetry indices of other ground reaction force components and their time to peak, impulses and vertical loading rate between pre-test and post-test conditions.

Conclusion: Despite the high asymmetry values of the peak medio-lateral component and it’s time to peak in children with flexible flat feet during pre-test; long-term use of the foot orthoses did not show any significant effect on the improvement of the asymmetry index of these components. However, long-term wearing of the foot orthoses reduced asymmetry index of the peak positive free moment amplitude.