Foot Model Problems-

Hello everyone,
I am having trouble getting the corrct muscle activation pattern on my 3-segment Foot model. I have attached the model here. I am driving the model with marker data for walking.

My main concerns is-
Tibialis Anterior(TibAnt) and Extensor Digotorum Longus (EDL) muscles show very high activity during stance phase of walking. They both should only be active during swing phase.

I suspect that these two muscles are trying to move the shank forward during stance, which should actually be controlled by knee joint motion. Model only has muscles below knee and Knee joint is not driven by muscles.

Is there something wrong with the model mechanics. Do I need to add any reaction at Hip or Knee joint?

Thanks for the help.