The Effect of Sport Shoes Outsole Containing Nano Silica on Vertical Loading Rate and the Magnitude of Vertical and Anterior-posterior Ground Reaction Forces During Stance Phase of Running

Using new materials of nanotechnology in sport shoe outsoles that can affect the ground reaction force components during stance phase of running have not been investigated in the literature.  The aim of this study was to investigate the effect of shoe outsole made by composite of thermo plastics elastomer and Silica nanoparticles on mean of active force, passive force, propulsive force and braking force and vertical loading rate compared to polyvinyl chloride shoe outsole during stance phase of running. 15 male ran on a force plate at 3.5m.s-1 under barefoot and shod conditions. The mean of vertical and anterior-posterior ground reaction forces and vertical loading rate were statistically analyzed using paired t-tests (α£0.05). Results showed that mean of active force, passive force; propulsive force and vertical loading rate were significantly increased by the in Nano composite shoe compared to polyvinyl chloride shoe (α£0.05). Also, Nano composite shoe caused to increasing in mean of active force, passive force, propulsive force and loading rate 7%, 3.74%, 2.09% and 6.06%, respectively. Nano composite shoe with hardness of 70 shores A was caused to increasing in mean vertical ground reaction force and mean propulsive force compared to polyvinyl chloride shoe with hardness of 65 shores A. This increase probably is because of the Tensile strength that caused by Nanosilica and could improve sport performance. However, increased vertical loading rate as result of using Nano composite shoe may predispose runners to running related injuries.