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 consideration of relevant biomechanical measures, a convention identifying toe-off as the beginning of the gait cycle and presenting swing followed by stance phases is the superior convention. Net joint torques and electromyographic(EMG) data from selected muscles in the lower extremity were obtained from four subjects while walking and running. Data were collected for consecutive swing, stance and swing phases to compare the variables at the swing-to-stance and stance-to-swing transitions. Larger joint torques were observed at the swing-to-stance transition at the hip and knee for both gaits compared to the other transition. EMG results showed greater activation levels for five of the six muscles at the swing-to-stance transition. Results indicated that the subjects needed to prepare for the initiation of stance and the application of relatively large external forces and moments. Further, the transition from 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 case, 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 middle of the analysis.