Effect of locking joint on Muscle Force

[Priyanshu Agarwal]

Hi,

While performing static optimization to calculate individual muscle forces the lock/unlock state of unactuated joints makes considerable changes in the muscle forces. When the analysis is carried out the joint coordinates are already set (no change in value for unactuated joints) in the .mot file, then why the lock/unlock state of the unactuated joint make a difference. Also, is the locked joint makes the two bodies a single rigid body in which case the joint can sustain some moment. However, actually a joint can never apply moment on its own (without muscles). What is the cause of appreciable changes in muscle forces?