THE SELECTION OF A STANDARD CONVENTION FOR ANALYZING GAIT DATA-BASED ON THE ANALYSIS OF RELEVANT BIOMECHANICAL FACTORS

The gait cycle is usually analyzed using one of two conventions: heel contact initiates the cycle and stance is followed by swing phases or toe-off initiates the cycle and swing then stance phases are analyzed. The purpose of the study is to demonstrate that based on a considerat ion of relevant biomechanical measures, a convention identifying toe-o ff as the beginning of the gait cycle and presenting swing followed by stance phases is the superior convention. Net joint torques and elect romyographic(EMG) data from selected muscles in the lower extremity we re obtained from four subjects while walking and running. Data were co llected for consecutive swing, stance and swing phases to compare the variables at the swing-to-stance and stance-to-swing transitions. Larg er joint torques were observed at the swing-to-stance transition at th e hip and knee for both gaits compared to the other transition. EMG re sults showed greater activation levels for five of the six muscles at the swing-to-stance transition. Results indicated that the subjects ne eded to prepare for the initiation of stance and the application of re latively large external forces and moments. Further, the transition fr om stance to swing did not seem to be as critical a point in the gait cycle since the moments and EMG were relatively low. This being the ca se, the stance-to-swing transition should be used as the beginning and ending of the gait cycle (toe-off initiating the cycle) and the more meaningful transition of swing-to-stance phases should occur in the mi ddle of the analysis.