Hi Pavel,
I have changed both the cervical and lumbar disc stiffness from linear to non-linear before you ran it and I also found the joint reaction force values has improved.
I supposed as you say, the (assumed) disc stiffness will play a major role in the accuracy.
As for orientation of the frame, I have changed the orientation of the gravity as per suggestion in the forum and here. It still however remain unchanged. Is there any other way for me to change this (as I have tried looking around the forum for GRF Prediction re-orientation but to no avail)?
Let me know.
Thank you.
F
