Lower extremity kinematics during forward heel-slip

BACKGROUND: Most fall intervention studies attempted to improve the mobility, range of motion of upper and lower extremities, or all major muscle strengths. Yet, there has been little effort to identify movements or actions that may be mainly responsible for recovering from a slipping. It was imperative to link lower extremity kinematics in conjunction with the functional anatomy of lower extremity muscles during forward heel-slipping to identify what muscles should have been activated substantially if a person would have recovered from forward heel-slipping. OBJECTIVE: The present study investigated lower extremity movements, such as the ankle, knee, and hip rotations, which could contribute to falls from forward heel-slipping. Determining changes in positions of foot, shank, and thigh during slipping would provide information to develop the optimal training regimen or interventions that may be effective for improving a chance to recover from the postural disturbance. METHODS: Twenty healthy adults (24–68 years old) participated in this experiment. Among twenty participants, only eight participants’ data were analyzed in this study. The 3D position data were used to compute the sagittal foot, shank, and thigh angles and frontal thigh angle. RESULTS: The study results indicated that, during the period of slipping, the angles of the segments of the slipping leg were different from that of the foot, shank, and thigh when walking ordinarily over the dry surface in the present study. CONCLUSIONS: The characteristics or differences in the angular kinematics of lower extremity during unexpected slips in the present study demonstrate possible causes for slip-induced falls.