TIME AND FREQUENCY-DOMAIN ANALYSIS OF GROUND REACTION FORCES DURING WALKING - AN INVESTIGATION OF VARIABILITY AND SYMMETRY

The purpose of this study was to investigate the variability and symme try of ground reaction force (GRF) measurements during walking, using time and frequency domain analysis. Means and standard deviations of s elected GRF time and frequency domain parameters for the left and righ t sides were calculated from 10 trials of each side. The results showe d that a 10-trial mean GRF frequency content meets acceptable variabil ity limits (<10%), and confirms the hypothesis of gait symmetry. The t ime domain variable results in the vertical and anterior-posterior dir ections agree with previous findings. In contrast, time domain paramet ers in the medial-lateral component are characterised by substantial a symmetries, probably due to the high variability found in this axis. R esults indicated that overall pattern examination of the GRF curves us ing frequency analysis instead of isolated time domain parameters, is a more appropriate procedure for GRF comparisons.