DETERMINATION OF HEEL STRIKE AND TOE-OFF IN THE RUNNING STRIDE USING AN ACCELEROMETER: APPLICATION TO FIELD-BASED GAIT STUDIES

Abstract

This study examined the validity of using an accelerometer to determine heel strike and toe-off during the running stride for use in field-based gait studies. Synchronised ground reaction force and accelerometer (±1.25Gz and ±12Gz) data were collected from six males running at constant speed across a force plate. Two attachments sites for the accelerometer were examined, the hip and the ankle. Attachment of the accelerometer to the ankle provided a highly distinguishable and repeatable pattem. The identification of heel strike and toe-off via the accelerometer signal was determined by calculation of the lag time from the acceleration peak after ground impact. The lag times were calculated to be 65±5msec for heel strike and 15±2msec for toe-off. The results of this stUdy provide evidence that heel strike and toe off can be accurately determined using an accelerometer.