I’m using a modified GaitFullBody mo-cap driven model. I have run some simulations and exported CorrectedActivity for several muscles on the upper body. I’m exploring with the different muscle recruitment strategies and have noticed that some CorrectedActivity values are negative. I’m not sure if this is an error in the model, or what negative muscle activity values are supposed to represent. Any guidance, please?
Muscle activation would be “Activity” in the muscle model outputs and not the “CorrectedActivity”.
The 3-element muscle model in AnyBody is linearized for the activation at each time step of the simulation, which might create some errors due to that. These errors are reflected in the CorrectedActivity. However, this error is normally negligible, unless the nonlinear dynamics are not captured well in the assigned time steps as the linearized model. Therefore, please inform what the movement and its approximate speed are. If the movement is fast, you can try to increase the number of simulation steps and monitor the changes.
Also, does this negative CorrectedActivity happen for all muscle recruitment cases?
Mohammad S. Shourijeh, PhD
AnyBody Team