We use the HUMAC dynamometer to measure ankle passive resistance torques during continuous passive motion as well. You can see our plots below.

Without knowing your dynamometer setup (prone vs. supine), it would appear that the direction of the resistance torque changes directions as 11 degrees. Note that when running the dynamometer for the supine position on the right limb, DF is negative rather than positive. We correct for this in MATLAB. If you are in either position, consider if the 11 degree ankle position is actually associated with the point at which the foot is vertically oriented. If this were the case, it could cause your resistance torque to change directions based on gravity.

In our study we plot ankle position-time, torque-time and torque-angle for our analyses. If we can be of greater support, please feel free to email me at

Powell_ankle rigidity.jpg