Joint reaction analysis in prosthetic gait model

[Sofie Ludvigsson]

Hi,
I'm trying to perform a joint reaction analysis on a gait model that I've adapted for transfemoral amputation from Gait 2392. I want to analyse the reaction forces in the different joints of the body. To do this I've performed Inverse Kinematics, Static Optimization and finally Joint Reaction. I've looked at the Youtube-tutorial for joint reaction analysis, but I can't seem to get any useful results. The forces in the left knee joint (the prosthetic one) look okay, but for the right joint (the regular knee), the results are very weird and don't look like they're expected to. I've attached an image of the results, showing both the left and the right knee and the forces in all three directions.

Does anyone have an idea of what could be wrong or what I could try changing to get the expected results? The knee angles look okay for both legs so the problem seems to appear after the Inverse kinematics analysis.

Best regards,
Sofie

[Colin Smith]

If you run inverse dynamics does the right knee joint torque look reasonable?

Just a guess, but may want to check the ground reaction forces on the right side.

[jimmy d]

I agree with Colin. I would check to make sure that i) your joint torques are as expected and ii) your muscles forces are correct. Have you performed RRA before running static optimization?