The purpose of this study is to implement current physiological findings about mechanical properties of whole muscles into the OpenSim platform, and to validate the performance of existing and enhanced muscle models. Recent testing and validation of the muscle models with experimental work has shown that muscle models with independent fast- and slow-contracting elements can predict muscle force better and more accurately than previous Hill-type models with only a single contractile element. We have developed a plug-in muscle model to achieve this property in OpenSim, supported by an OpenSim pilot project grant. Recent testing shows that the new plug-in module generates the expected changes in contractile performance when the proportion of fast- to slow- activation is changed. We are currently collecting experimental data to test the validity of the constant-thickness assumption of the existing muscle model, and propose to incorporate more structurally relevant properties if they improve the accuracy of the muscle model.


Publication overview
Wakeling, J.M., Lee S.S.M., Arnold A.S., de Boef Miara, M., & Biewener, A.A.. A muscle's force depends on the recruitment patterns of its fibres. Ann. Biomed. Eng. 40, 1708-1720, (2012).
Wakeling, J.M. & Randhawa, A. 1D, 2D and 3D structural models for Hill-type muscle models. Computer Methods in Biomechanics and Biomedical Engineering (11th Int. Symposium). Salt Lake City, UT, (2013).
Lee, S.S.M., deBoef Miara, M, Arnold, A.S., Biewener, A.A., Wakeling, J.M. “Hill-type muscle model with slow and fast fiber contractile elements”. Annual Meeting of the American Society of Biomechanics, Omaha, NB, (2013).
Lee, S.S.M., deBoef Miara, M, Arnold, A.S., Biewener, A.A., Wakeling, J.M. “A two-element Hill-type model to predict muscle forces”. Society of Comparative and Integrative Biology Annual Meeting, San Francisco, CA, (2013).
Lee, S.S.M., de Boef Miara, M., Arnold, A.S., Biewener, A.A., Wakeling, J.M. Accuracy of gastrocenmius forces in walking and running goats predicted by one element and two-element Hill-type models. J. Biomech. In press.