Gait2392 Issue with locking model in place

[Om Vishanagra]

Hello,

The current project my team is working on requires us to lock the Gait2392 Simbody in a seated position while applying a load to the right shank of the tibia. We are attempting to run the simulation (Static Optimization, RRA, and CMC) while applying an external load without moving the leg.

Currently, even with all other coordinates locked in position, when we run the simulations mentioned above, the leg rotates about the knee in a clockwise motion, followed by a counterclockwise motion about 50% through the simulation.

If anyone has attempted to run a similar simulation to our application and understands how to effectively obtain the data from these simulations while keeping the knee locked in a fixed position your help would be greatly appreciated.

Thank you, any information helps greatly!