Estimation of lower limb muscle forces during human sit-to-stand process with a rehabilitation training system

As it is inconvenient to directly measure tension forces of muscles attaching on limbs, a new quantitative method for estimating muscle forces of lower limb was presented based on a developed rehabilitation training system and AnyBody Modeling System. In the AnyBody Modeling System, which professionally concerns on musculoskeletal kinematic modeling and analysis, quantitative results of muscle forces can be calculated through an inverse dynamics method. In this study, a musculoskeletal model composed of thigh, shank and foot was established in the AnyBody Modeling System, and an experiment was performed to acquire dynamics parameters of body segments with the rehabilitation training system during the sit-to-stand process. Then tension forces of muscles of lower limb were calculated through the inverse dynamics analysis, and the calculated results matched the muscle activation level tendency of electromyography (EMG) method, which was also adopted in the experiment for validation. The method for estimating muscle forces appears to be a practical means to determine muscle forces in musculoskeletal analysis of human limb.