Analysis of muscle forces in lower limbs based on wearable sensors

Human foot is a complex musculoskeletal system. As it is impossible to directly measure the force of muscle attaching with limbs, a new quantitative method for dynamics analysis of human ankle muscle forces is presented by using the AnyBody Modeling System and a developed wearable motion and ground reaction force (GRF) sensor system. The sensor system can be used to continuously measure human motion and GRF in various environments, not limited to measurement of level walking in a laboratory environment. 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 the shank, anterior and posterior parts of the foot was established in the AnyBody Modeling System, and then the motion and GRF were measured using the sensor system on 8 volunteers (age: 29±4 years) during normal speed gait. Muscle tension force estimation based on the inverse dynamics analysis was implemented and the results matched the variation tendency of electromyography (EMG) results reported by a literature. This method for dynamics analysis of human foot appears to be a practical means to determine muscle forces in musculoskeletal analysis of human limb.