Fig. 4.

We compared induced motion measures to perturbations of subject-specific gait simulations. To do this, we first computed nominal muscle excitation patterns that drove a forward dynamic musculoskeletal model to emulate measured gait kinematics. We then introduced small (0.01 to 0.1 units for 100 ms) increases in the rectus femoris’ nominal excitation at either 50% or 60% of the gait cycle, and re-simulated the gait cycle. The simulated changes in hip and knee flexion were compared to the same measures determined experimentally. Notation: GM-gluteus maximus, VL-Vastus Lateralis, RF-Rectus Femoris, SOL-Soleus.