This generic rigid-body upper-limb musculoskeletal model may be employed to estimate the forces in the shoulder muscles given pre-defined upper limb motion and external forces.

The muscle-tendon paths have been optimised to data derived from one comprehensive set of muscle moment arm experiments performed in vitro. Musculotendon parameters have calculated using an optimization routine from sets of isometric and isokinetic tasks performed one generic healthy individual. A customised static optimization function was written in Matlab to add constraints on the glenohumeral joint force direction. This is required to ensure that the calculated muscle forces produce sufficient stabilising glenohumeral joint compression. The optimiser utilizes OpenSim and the C++ API.

The downloadable project is provided, including relevant files for performing muscle and joint force estimation, as well as setup instructions. An example shoulder motion from one healthy subject during coronal-plane abduction is also provided.

Please cite the following paper when using the model:
Wu, W., Lee, P. V. S., Bryant, A. L., Galea, M., & Ackland, D. C. (2016). Subject-specific musculoskeletal modeling in the evaluation of shoulder muscle and joint function. Journal of Biomechanics, 49(15), 3626–3634.