OpenSim and Simbody provide a generalized method for calculating biologically meaningful muscle moment arms in complex multibody biomechanical models.
Describes how OpenSim and Simbody resolve biomechanical modeling challenges to calculate biologically meaningful muscle moment arms.
Biomechanics researchers often use multibody models to represent biological systems. However, the mapping from biology to mechanics and back can be problematic. OpenSim is a popular open source tool used for this purpose, mapping between biological specifications and an underlying generalized coordinate multibody system called Simbody. One quantity of interest to biomechanical researchers and clinicians is "muscle moment arm," a measure of the effectiveness of a muscle at contributing to a particular motion over a range of configurations. OpenSim can automatically calculate these quantities for any muscle once a model has been built. For simple cases, this calculation is the same as the conventional moment arm calculation in mechanical engineering. But a muscle may span several joints (e.g., wrist, neck, back) and may follow a convoluted path over various curved surfaces. A biological joint may require several bodies or even a mechanism to accurately represent in the multibody model (e.g., knee, shoulder). In these situations we need a careful definition of muscle moment arm that is analogous to the mechanical engineering concept, yet generalized to be of use to biomedical researchers. Here we present some biomechanical modeling challenges and how they are resolved in OpenSim and Simbody to yield biologically meaningful muscle moment arms.
Sherman et al. (Sun,) conducted a other in Biomechanical modeling. OpenSim and Simbody was evaluated. OpenSim and Simbody provide a generalized method for calculating biologically meaningful muscle moment arms in complex multibody biomechanical models.