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 symmetry of ground reaction force (GRF) measurements during walking, using time and frequency domain analysis. Means and standard deviations of selected GRF time and frequency domain parameters for the left and right sides were calculated from 10 trials of each side. The results showed that a 10-trial mean GRF frequency content meets acceptable variability limits (<10%), and confirms the hypothesis of gait symmetry. The time domain variable results in the vertical and anterior-posterior directions agree with previous findings. In contrast, time domain parameters in the medial-lateral component are characterised by substantial asymmetries, probably due to the high variability found in this axis. Results indicated that overall pattern examination of the GRF curves using frequency analysis instead of isolated time domain parameters, is a more appropriate procedure for GRF comparisons