Algorithms for Calculating Moment Arm

[Shuo Chen]

Hi,
I am a new user of Opensim 4.3 and have limited knowledge of codding. I know we can easily plot the moment arm of the muscles over the joint angle, but I don't know the algorithms after that. Is there any reference/paper indicating related information?
Specifically, I want to know if there is any differences between the calculation of monoarticular and biarticular muscle moment arm. Beside that, I also want to know if there is any differences between Raj. model and general model to calculate muscle moment arm?

Thanks advance,

[Thomas Uchida]

There are some publications listed under "Theory and Publications" on the OpenSim Documentation site: https://simtk-confluence.stanford.edu:8 ... blications. See, in particular, "What is a moment arm? Calculating muscle effectiveness in Biomechanical models using generalized coordinates" under "Dynamics Theory": https://simtk-confluence.stanford.edu:8 ... ics+Theory. Moment arm calculations do not differ between models, but a particular muscle's moment arm curve may be different depending on how the muscle's path has been defined in that model, the range of motion over which the model has been validated, whether the model has been scaled, etc.

[Shuo Chen]

Thank you for your kind and quickly reply.