The influence of slow recovery insole on plantar pressure and contact area during walking

Plantar pressure assessment is commonly used as a tool to assess the efficacy of insoles in reducing the risk of mechanical trauma to the plantar soft tissue during walking gait. The slow rebound (SR) Poron insole is intended to provide a custom fit to the foot and is believed to be superior in increasing the contact area and consequently reducing the contact pressure compared to a normal Poron (NP) insole. The aim of this study was to compare the effectiveness of SR or NP versus an ethylene vinyl acetate (EV) insole in increasing the contact area (CA), and in reducing the contact pressure (CP) at different regions of the foot during walking. Plantar pressure data was collected from nine healthy individuals during walking using commercially available in-shoe plantar pressure sensors. Although, the NP insole significantly increased the CA and decreased the CP on the entire foot compared to the EV, there was no significant change in CP or CA at any region of the foot in any of the tested insoles. CP showed a positive significant correlation with CA at heel, hallux and heel center in all three insoles. The expected significant negative correlation between regional CA and CP was not observed.