Review of Modelling Techniques for In Vivo Muscle Force Estimation in the Lower Extremities during Strength Training

Figure 2

The Hill-type muscle-tendon model, showing muscle and tendon forces (, ), as well as the series-elastic (SE), parallel-elastic (PE), and contractile (CE) elements of the muscle length () and stiffness () of the whole muscle-tendon actuator (, ). represents the activation of the CE (adapted from Pandy and coworkers [12]).