The acute effects of the application of arch support insole on ground reaction forces during walking

Evaluation of ground reaction forces (GRF) and other kinetic factors have clinical importance. There is interaction between shoe type and insole with these factors. The objectives of this study were to assess the acuteeffects of arch support insole on GRF and their time-to peak of each reaction force, impulse, loading rate, and free moment during stance phase of gait in normal individuals.
Sixteen healthy male subjects with mean age, mass and height of 29.4±4.8 years, 77.9±12.6 kg, and 176.5±5.8 cm, respectively, participated on this study. Using two adjacent Kistler force plates (1000Hz) GRF during stance phase of walking with and without shoe insole were measured. Then, maximum GRF and their related time-to-peak, impulse, loading rate, and free moment were obtained. Repeated measure ANOVA was used to analyze the data (α=0.05).
Wearing insole caused reduction of the peak vertical GRF on heel contact by 6.9% of body weight (BW) (p=0.001) and the loading rate (8.4%, p=0.02), while it increased the propulsive force (7% N/BW, p=0.001), anterior-posterior impulse by 1.2% BW.s (p=0.003) and normal impulse by 2% of BW.s (p=0.032).
Reduction of the vertical GRF and loading rate by means of insole may reduce the risk of lower extremity injuries due to impulse during walking. Arch supportinsole application can prevent sport injuries by reducing the reaction forces.