Kinematics, kinetics and muscle activities of the lower extremity during the first four steps from gait initiation to the steady-state walking

In this study, biomechanical characteristics during the whole process of gait initiation for twenty normal healthy volunteers were determined by the motion analysis with six near-infrared cameras, four forceplates, and an EMG system. Gait initiation, a transitional movement phenomenon from quiet stance to steady-state walking, involves a series of muscular activities, GRFs, movements of COP and COM, and joint motions. Results showed that the location of the net COP to be most lateral during double limb stance at the beginning of gait initiation. During gait initiation, changes in anteroposterior components of GRFs were first found and then changes in vertical components followed. Hip and knee motions were found before the ankle joint motion. Walking speed, step length, and stride length gradually increased until the second step. The interaction between the COM and COP is tightly regulated to control the trajectory of the COM and thereby control total body balance. This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo Sun-Woo Park received a B.S. degree in Biomedical Engineering from Yonsei University in 2006. He is currently a M.S. candidate in the Department of Biomedical Engineering, Yonsei University, Korea. His research interests in the area of Human Movement and detection of gait phase using motion sensors. Hue-Seok Choi received a B.S. degree in Computer Engineering from Daejeon University in 2004. He is currently a P.D. candidate at the Department of Biomedical Engineering at Yonsei University, Korea. His research interests are in the area of Human Movement and Rehabilitation Engineering. Ki-Hong Ryu received a B.S. and M.S. degrees in Biomedical Engineering from Yonsei University in 1998 and 2001, respectively. He is currently a P.D. candidate in the Department of Biomedical Engineering, Yonsei University, Korea. His research interests are in the area of Human Movement and Gait Training System using Functional Electrical Stimulation. Sa-Yup Kim received a B.S. degree in Electrical Engineering from Yeungnam University in 2002 and M.S. degrees in Biomedical Engineering from Yonsei University in 2006. He is currently working from Korea Institute of Industrial Technology in Cheonan, Korea. Young-Ho Kim received a B.S. degree in Mechanical Engineering from Hanyang University in 1982. He then went on to receive his M.S. and Ph.D. degrees from University of Iowa in 1989 and 1991, respectively. He is currently a Professor in the Department of Biomedical Engineering, Yonsei University, Korea. His research interests are in the area of Human Movement, Rehabilitation Engineering, and Biomechanics.