A simple method for determination of gait events

Simple and effective methods for determining the timing of gait events are necessary for the proper normalization and statistical analysis of gait data when a variety of gait measurements are available. The approach presented was developed for cases in which overall center of pressure under the body and marker trajectories are being measured over multiple steps. The new method presented uses the relative positioning of the overall center of pressure and an ankle marker in the direction of forward progression for the determination of "heel-contact" and "toe-off" events. The difference between the locations of the overall center of pressure and the ankle in the direction of progression readily delineates the timing of these events. The new method was tested against force records from individual force platforms and was found to detect "heel-contact" events an average of I sample (at a sampling frequency of 120 Hz. 0.00833 s) before the event found using the individual force platforms. "Toe-off" events were found an average of 2 samples (0.0167 s) prior to the events found using individual force plates. The method appears new and is attractive because of its simplicity in determining gait events when the appropriate gait measurements are available. (C) 2002 Elsevier Science Ltd. All rights reserved.