Problems with muscle activation in CMC

[Nelson Xiang]

I'm working on my project of obtaining the muscle activation of a walking person using CMC in Opensim 4.1. I mainly foucs on four muscles: gaslat, gasmed, soleus, tibant.

The muscleskeletal model I used is a fullbody model developed by Rajagopal's team. In this project, I first conducted a motion capture experiment. A person walks on the treadmill. The positions of markers attached to his body are recorded by th motion capture system. And the grounded reaction force is recorded. Then I conducted inverse kinematics (IK) in Opensim 4.1 to obtain a motion simulation of the person's wakling. Finally I conducted CMC using the motion obtained in IK and GRF obtained in experiment to get the muscle activation. I plotted the four muscle's activation:
https://ibb.co/w09fYHm
The plot shows that the activation of gas_lat_r reaches 1 in part of a gait period. However, the proper activation should be no more than 0.6 during the whole gait period.

From the following 3 pictures, we can see that the ground reaction force is in the normal range.
https://ibb.co/LNmqkBP
https://ibb.co/K5PT2Rk
https://ibb.co/Dg9DHQg
Could you please help me with this problem? Is there any possible reason or solution, or any possible ways to debug this?

Thanks very much!