2011 Volume 6 Issue 4 Pages 299-310
Human foot is a complex musculoskeletal system. As it is inconvenient to directly measure tension forces of muscles attaching on limbs, a new quantitative method for dynamics analysis of muscle forces of ankle joint was presented based on a developed wearable motion, ground reaction force (GRF) sensor 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 the shank and multiple-units foot was established in the AnyBody Modeling System, and an experiment was implemented with the wearable sensor system on eight volunteers during their normal gait. Tension forces of muscles of ankle joint were calculated through the inverse dynamics analysis, and the results matched the muscle activation level tendency of electromyography (EMG) method, which was implemented in the experiment as a contradistinction. The method for estimating muscle forces of ankle joint in the study appears to be a practical means to determine muscle forces in musculoskeletal analysis of human limb, and the system may be used as a convenient instrument for on-the-spot medical applications.