Article

We investigated the individual muscle contribution to arm motion to better
understand the complex muscular coordination underlying three-dimensional (3D)
reaching tasks of the upper limb (UL). The individual contributions of biceps,
triceps, deltoid anterior, medius, posterior and pectoralis major to the control
of specific degrees of freedom (DOFs) were examined:
using a scaled
musculoskeletal model, the muscle excitations that reproduce the kinematics were
calculated using computed muscle control and a forward simulation was generated.
During consequent perturbation analyses, the muscle excitation of selected
muscles was instantaneously increased and the resulting effect on the specific
DOF was studied to quantify the muscle contribution. The calculated muscle
contributions were compared to the responses elicited during electrical
stimulation experiments. Innovative in our findings is that muscle action during
reaching clearly depended on the reaching trajectory in 3D space. For the
majority of the muscles, the magnitude of muscle action changed and even reversed
when reaching to different heights and widths. Furthermore, muscle effects on non
spanned joints were reported. Using a musculoskeletal model and forward
simulation techniques, we demonstrate individual position-dependent muscle
contributions to 3D joint kinematics of the UL.
CI - Copyright (c) 2012 Elsevier B.V. All rights reserved.

Langue : ANGLAIS