Page 1 of 1
Muscle Stiffness
Posted: Tue Jul 23, 2013 9:32 am
by mraabe12
I am interested in increasing/decreasing muscle stiffness of certain muscles in a model. What property of the muscle would I change to do this? The FmaxMuscleStrain property is the passive muscle stiffness, but is there a way to change the active muscle stiffness? Thanks!
Margaret
Re: Muscle Stiffness
Posted: Sat Jul 27, 2013 10:28 pm
by tkuchida
Hi, Margaret.
The force-length relationship for the active element is described by the active-force-length curve.
If you are using the Thelen2003 muscle model, adjusting the KshapeActive parameter will change the shape of the Gaussian used to model this relationship (see the attached image). KshapeActive is equivalent to gamma in equation (4) of Thelen's paper (
http://homepages.cae.wisc.edu/~thelen/pubs/jbme03.pdf).
If you are using the Millard2012Equilibrium muscle model, several parameters can be used to adjust the shape of the active-force-length curve. Please see the Confluence page (
http://simtk-confluence.stanford.edu:80 ... cle+Models) or ASME paper (
http://dx.doi.org/10.1115/1.4023390) for details.
Hope that helps.
Tom