An EMG-assisted kinetics model for human knee system

The knee system is very important and probably the most studied joint system in the human body. This study was designated to study the myoelectrical and biomechanical properties of the knee muscles, to develop kinetic models for the related muscles, and then to incorporate the skeletal structure, muscle models, and system engineering theories to build a kinetic model for the isometric contraction of the knee system. Surface EMG was used as an indicator of the muscle activity. The mechanical properties of the muscle at different joint angle were measured to provide data for both modeling and model evaluation. A Hill-type muscle-skeletal model was developed based on the activation dynamics and the torque-angle properties of the muscle to simulate the mechanical properties of human knee system. This model was also used to study the movement changes of the knee system in the patellofemoral joint (PFJ) malalignment patients from the pattern changes of surface EMG. The changes in the EMG patterns of the PFJ patients' quadriceps muscle resulted in changes in model output torque. The results showed that, by analyzing the changes in the model parameters, this model has the potential to be clinically used in the assessment of human knee illnesses.