Torque Sharing of the Quadriceps Muscles Estimated by Emg-driven Model and Surface Electromyographic of Vastus Intermedius

EMG-Driven models predict individual muscle forces, but it is necessary to obtain muscle electromyography (EMG), which is difficult for deep muscle, as vastus intermedius (VI). The purpose of this study is to determine the relative contribution of each quadriceps (QF) components to the knee extension torque by EMG-Driven model, with a protocol of surface VI EMG acquisition, at submaximal isometric contractions around 20% and 60% of maximum voluntary contraction (MVC). Surface EMGs were acquired from VI, vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM) muscles. The EMGs were filtered, rectified and normalized to enter the EMG-Driven model as excitation signals. The QF components contributions were for 20%MVC: 28% for VI, 31% for VL, 17 for RF and 24% for VM; for 60%MVC: 27% for VI, 32% for VL, 15% for RF and 26% for VM. Only RF contribution was significantly smaller than the other muscles, for both 20% and 60% MVC.