US Patent 7793437 Shoe sole

Shoe sole that promotes a natural walking gait by promoting the natural step motion of a barefoot person walking in sand. The shoe sole has is a single-shot injection molded sole that has a continuously, irregularly curved lower surface and a multi-contoured upper surface. The lower surface has a radius of curvature in the heel area that is smaller than the radius of curvature in the toe area. The upper surface has an arch support, a depression for cradling the ball of the foot, and flex zones that promote flexing of the shoe sole in the longitudinal and transverse direction.