degree of freedom at knee joint

[Rohan Kothurkar]

I aimed to enhance the degree of freedom in the knee joint of Rajagopal Model, which currently has only one degree of freedom.
If I were to modify your model to increase the degree of freedom, would that be acceptable, or would it be considered inappropriate without ligaments?

[Mohammadreza Rezaie]

Hi, it depends on your research question. You can find a model with knee ligaments and more knee DoF here: https://simtk.org/projects/opensim-jam

But generally, it might not be a good idea. Because the other knee DoFs cannot be measured accurately using skin mounted markers [1] and it leads to inaccurate and unreliable muscles kinematics, abnormal muscles activity/force, and hence, knee joint contact force. Please see this:
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viewtopicPhpbb.php?f=91&t=12919&p=0&sta ... eec78cd468

[1] Benoit et al. (2006). Effect of skin movement artifact on knee kinematics during gait and cutting motions measured in vivo. https://doi.org/10.1016/j.gaitpost.2005.04.012

[Rohan Kothurkar]

Dear Mohammadreza Rezaie,
Thanks
Prof. Bogert's response was convincing. What if I include knee ligaments in the Rajagopal model?
Example : https://simtk.org/projects/kneemodel/

Kind Regards,
Rohan