Simultaneous estimation of ground reaction force and knee contact force during walking and squatting

Abstract

Chronic occupational lower limb injuries such as osteoarthritis require an understanding of mechanical loading conditions in joints during occupational activities. We aimed to develop a human musculoskeletal model and to estimate knee contact force and ground reaction force (GRF) simultaneously during walking and squatting. GRF and joint kinematics were obtained from a subject with electronic total knee replacement during walking and squatting. Force reaction elements were embedded in the knee and foot of a full-body musculoskeletal model. The joint kinematics and ground vertical force were applied to the musculoskeletal model to estimate ground shear force and knee contact force using an inverse dynamics-based optimization. Ground shear force and knee contact force could be estimated simultaneously with root mean square (RMS) error less than 1.6% body weight (BW) and 35% BW, respectively. Simultaneous estimations could be accurately conducted but the RMS error for the knee contact force increased by approximately 10% BW.