Least-action principle in gait

Abstract

We apply the laws of human gait vertical ground reaction force and discover the existence of the phenomenon of least-action principle in gait. Using a capacitive mat transducer system, we obtain the variations of human gait vertical ground reaction force and establish a structure equation for the resultant of such a force. Defining the deviation of vertical force as an action function, we observe from our gait optimization analysis the least-action principle at half of the stride time. We develop an evaluation index of mechanical-energy consumption based upon the least-action principle in gait. We conclude that these observations can be employed to enhance the accountability of gait evaluation. © 2009 Europhysics Letters Association.