From Marker Trajectories to Muscular Activations: A Musculoskeletal Multibody Model Considering Compliant Tendon Behaviour

In this paper a recent development about the multibody modelling of musculoskeletal system is presented. The authors implemented two new routines in the already developed algorithm simulating the inverse dynamics of musculoskeletal systems able to elaborate the driving actions that lead the system to move with a known kinematics. The routines added to the algorithm were the inverse kinematics tool and the consideration of the tendon compliant behaviour: the first made the code able to elaborate the evolution of the system degrees of freedom starting from a set of marker trajectories, while the second allowed to consider the deformability of the tendons included in the muscle actuators. The upgraded model was tested on an upper limb musculoskeletal system available on the OpenSim® software and the results were shown and discussed, focusing on the comparison between the configurations of rigid/compliant tendon possibility. The positive outcomes and the adaptability of the developed code allowed the authors to consider the utilization of the algorithm in the framework of the biotribological assessment of artificial joint, like the total hip replacement implanted in the lower limb system.