Characterization of human gait by means of body center of mass oscillations derived from ground reaction forces

Ground reaction forces from two force plates are used to determine the cyclic oscillations of the body center of mass while walking at preferred speed. Good approximations to the oscillations may be obtained from formulae containing just the first-and second-order Fourier coefficients of the combined left-right ground reaction forces taken over a complete walking cycle. The symmetric components of the oscillations have consistent mutual phase relations for normal subjects, so that the amplitudes alone can be used as sufficient parameters to characterize the body center of mass oscillations. The analytical technique enables detection of small but consistent gait asymmetries.