A system to measure the forces and moments at the knee and hip during level walking

The forces and moments in the sagittal plane at the knee and hip were calculated using gait data collected during level walking. Accelerations were measured by accelerometers attached to the legs, and the force reactions at the foot were measured by a force plate. The recorded accelerations and the foot forces were used to determine the joint reactions through a Newtonian formulation modeling the leg as articulated, rigid links. Twelve normal subjects were included in this study along with nine lower limb amputees. Obvious differences were observed when comparing amputee data to normal data both at the knee and hip. Gait data obtained by this system can be readily used to form criteria for objective gait analysis and improved prosthesis design.