How sensitive are the results to the number of muscles included in the model?
This is not easy to answer accurately. Of course, all major muscles are important, their strength properties as well as their moment arms. In order to model moment arms reasonably, it is necessary to divide larger muscle into branches, so that the combined effort of the branches match the one of a complicated muscle complex. We believe that the model we have presented cannot be much simpler and still be a meaningful 3D model. On the other hand it is very difficult to find proper data for a more accurate model. There is certainly room for adjustments and improvements, which is also one of the ideas of the public repository, namely that all users can help each other improve the models.
