Impules and frequency responses of the antero-posterior and lateral sways in human standing posture were obtained by applying two dimensional autoregressive processes to the both sways.
The impulse response of antero-posterior direction due to an impulse-like lateral sway and that of lateral direction due to an impulse-like antero-posterior sway depicted an oscillatory time-pattern with a decay in its amplitude. The former, however, was far more prominent than the latter in its amplitude and duration. A dominant peak around 7-10Hz was observed in the frequency response (frequency pattern of the impulse response) of the former, whereas the peak was very minute in the latter.
