Figure 1.

(A): Simple biomechanical (dynamic) model of the upper extremity in OpenSim software. (B): Schematic drawing of the musculoskeletal model of the arm and Hill-type muscle unit, where contractile element (CE) is a contractile element, parallel (PE) is a parallel elastic element, series (SE) is a series elastic element, $l_{CE}$ is CE length, $l_{SE}$ is SE length.