Subtalar joint in gait2354 model

[Park SangJun]

hi
I have motion capture data for walking and sit to stand movements.
However, when this data is entered into the gait2354 model, the subtalar joint does not move.
I would like to analyze the ROM, moment, and contact force of the subtalar joint. How can I do this?
I need help
thank you

[Mohammadreza Rezaie]

Hi, make sure that subtalar coordinate is not locked in the Coordinates window. Its motion can be controlled by the Weights Pane in the IK tool. You must re-run the IK tool to see its motion.

[Park SangJun]

Hi mohammadreza thanks for your reply.
I will proceed according to your answer. I have one question. Regarding the marker weight and coordinate weight in the picture below, the marker weight seems to be weighted to follow the trajectory of the marker more appropriately, but if you enter a large number for the coordinate weight, the coordinate does not seem to move. Am I right?
and are the opensim gait 2354 model's subtalar joint kinetics and kinematics validated?
Thanks again for your reply

[Mohammadreza Rezaie]

I cannot see any image attached. You need to uncheck/disable the subtalar coordinate's weight if you want to see its motion. The location and orientation of subtalar joint is based on an old anatomical study, Isman and Inman (1976) [Ref1]. However, this is a fact that a one-segment foot model fails to capture subtalar joint motion accurately [Ref2]. So, you may see high variability in subtalar joint moment, and that's why it is locked in most muscle-driven simulations.


[Ref]

1. Delp, Scott L., et al. An interactive graphics-based model of the lower extremity to study orthopaedic surgical procedures. IEEE Transactions on Biomedical engineering 37.8 (1990): 757-767.
2. Pothrat, Claude, et al. One-and multi-segment foot models lead to opposite results on ankle joint kinematics during gait: Implications for clinical assessment. Clinical Biomechanics 30.5 (2015): 493-499.