simtk.org

Hi

We have walking data with two force plates.
After running an RRA, I found that the model is sinking a little bit into the ground, and I would guess this is related to the external force missing.
While the right leg is stepping (heel-contact) onto the 1st force plate, the left leg is still on the ground. The left leg GRF is not available as there is no force plate. So there is a small body sinking only at this right leg heel-contact (and then no more body sinking after the heel-contact until toe-off).
Although we are only looking at the right stance phase, I concern that if this body sinking due to no GRF from the left leg affects our gait results. Do you think this sinking body affect the results? If so, could we fix this problem?

Thanks,

This will definitely affect your end results. In general, we suggest that you should run any tools/analyses that depend on ground contact force only for the time periods that you have all external forces available. In your case, this sounds like you should only start using RRA, CMC or static optimization only after you think the left leg has entered swing phase.