Hi all, I have read that the muscle contraction force calculated by the Hill-type muscle model was comprised of two parts, the active force and the passive force. But i feel confused that when the passive force will happen? Does it happen when i actively contract my muscles? If it does not happen, i...

Hi, Sherm. You are right. I assume that the joint torque produced by muscles would equal to the torque obtained form inverse dynamics. For example, if the knee angle is a constant, f_unknown will equal to the amount of torque generated by gravity.


Bo Ding

Hello Sherm, Thanks for your reply. But I still feel confused. What does the f_unknown mean? Do you mean that the joint moment generated by muscles is comprised by the f_unknow and the ma ? If this is true, the observed human motion was resulted from only a small part of muscle forces. Regards, Bo D...

Hi all, I use the musculoskeletal model to calculate knee joint moment and use inverse dynamics to examine it. However, the moment obtained from forward is about 100Nm, while the results obtained from inverse dynamics is only 6Nm. I only take knee joint into account and the equation of inverse dynam...

Hi Simpson ,

Thanks for your reply. It did help.

Hi,


If I have the insertion coordinates and origin coordinates of a muscle, then how to calculte the muscle moment arm to knee joint during gait?

thanks
by Bo Ding

Hello,
I want to know if there are some devices to directly mesasure joint torque instead of using inverse dynamics.

thanks
bo ding

Hi all, Recently, i am studying Thelen2003Muscle model. I have found that the force-velocity curve was determinded by three parameters:Af, Flen and fv_liner_extrap_threshold in Opensim models. However, in Thelen's paper titled 'Adjustment of Muscle Mechanics Model Parameters to Simulate Dynamic Cont...

Hi James,

Thanks for your reply. Actually I had read the pages that you advised. I just want to know can i find the related code in OpenSim Sorce Code(since i have downloaded from the web) about force-generating process.

Thanks very much.

Bo Ding

Hi all, I want to have a better understanding of how muscle force was generated in opensim program. I looked for the Doxyen to see the functions related to it, but I only found the parameters that a function included and i can not find the details about how to implement it. I wonder can i find the d...