Inverse dynamics unexpected results (gait)

[Agathe Pesin]

Hi,

I used the inverse dynamics tool to get the joint moments for a gait trial but I have an issue issue with the results, they are very weird. You can see the attached plot of the knee moments. The moment profile is quite different than theoretical moments we can find in the litterature. Knee moments are never close to 0 while the plot represents the whole gait cycle and I expected them to be close to zero during the swing phase.

We collected data with a Codamotion system and Kistler forceplates, then we filtered forces and marker positions datas (15 Hz and 6 Hz respectivily). GRF files were generated with Matlab (MOtoNMS).
The inverse kinematics seem fine. You can see the attached plot of the knee angle (the line represent the right Toe-off). I also attached the GRF file.

Thanks for anyone who can help me,

Best regards,

Agathe