Too high ankle joint moment during running

[Bas Van Hooren]

Hi,

I want to use OpenSim to determine joint moments (and later on also muscle forces) during running using the Catelli model. The calculated joint moments for the knee and ankle do however not completely match the literature (see attached file). I have tried a lot of things to figure out what is going wrong but cannot find the issue. Some tips/help would be greatly appreciated.

Briefly, the ankle joint moments seem to be overestimated by 1-1.5 Nm/kg, while the knee joint moments seem to be underestimated by 1-1.5 Nm/kg when compared to the literature, and also when compared to the HBM2 model (see van den Bogert (2013)), which uses exactly the same marker and GRF data as input. Therefore, I do think the issue might be related to scaling of the model. Yet, visually the scaled model looks correct. Indeed, the kinematics and GRF seem to match the literature well and also match well between the models.

Joint moments comparison.gif (545.41 KiB) Viewed 119 times

Below I have added an image of the scale tool set-up I use. I have compared it to the set-up other people use and it does seem correct to me. The toe markers are attached to the toe segment in the model, but I have also tried connecting them to the calcaneus. Yet the ID results were exactly similar. Therefore I don't know what other aspects could be causing this issue and any suggestions are greatly appreciated.

scale tool.gif (679.03 KiB) Viewed 119 times