Experimental analysis of force moment about body center of mass during level walking using force plates

In this paper we report the characteristics of force moment about the center of mass (COM) of a human body during level walking at a steady pace, using two large force plates by which the three-dimensional floor reaction force components can be measured. The displacements of the COM in the three directions are obtained from the Fourier series of the reaction force components by double integration. The following results are obtained: although the three-dimensional reaction force components are large, the moment of force about the COM becomes very small, which suggests that a human walks producing as small a moment as possible about the COM of his/her body. In other words, only a negligible rotation about the COM occurs; the magnitude of the external moment applied at the sole is remarked in the moment of force about the vertical axis.