Effects of Optimization Technique on Simulated Muscle Activations and Forces.

Effects of Optimization Technique on Simulated Muscle Activations and Forces.
J Appl Biomech. 2020 Jul 14;:1-20
Authors: Roelker SA, Caruthers EJ, Hall RK, Pelz NC, Chaudhari AMW, Siston RA
Abstract
Two optimization techniques, static optimization (SO) and computed muscle control (CMC), are often used in OpenSim to estimate the muscle activations and forces responsible for movement. Although differences between SO and CMC muscle function have been reported, the accuracy of each technique and the combined effect of optimization and model choice on simulated muscle function is unclear. The purpose of this study was to quantitatively compare the SO and CMC estimates of muscle activations and forces during gait with the experimental data in the Gait2392 and Full Body Running models. In OpenSim (version 3.1), muscle function during gait was estimated using SO and CMC in 6 subjects in each model and validated against experimental muscle activations and joint torques. Experimental and simulated activation agreement was sensitive to optimization technique for the soleus and tibialis anterior. Knee extension torque error was greater with CMC than SO. Muscle forces, activations, and co-contraction indices tended to be higher with CMC and more sensitive to model choice. CMC's inclusion of passive muscle forces, muscle activation-contraction dynamics, and a proportional-derivative controller to track kinematics contributes to these differences. ...

Source: Journal of Applied Biomechanics - July 15, 2020 Category: Sports Medicine Tags: J Appl Biomech Source Type: research