The problem of MaxMuscleActivity>1 , C3D into MoCap-FullBody

[Snow (Snow Lee)]

I put C3D into MoCap-FullBody.main.any. The C3D shows lifting the barbell which Contains the three-dimensional force of the foot and the coordinates of the full-body’s marker points.And I made the body model work in MoCap-FullBody.main.any, inculding motion and parameter optimization sequence and inverse dynamics analysis sequence.But the result is bad. I get some problems,such as
1.MaxMuscleActivity>1,the max of MaxMuscleActivity I got is nearly 3.
2.Plantar pressure version is not in the correct position.
3.Whether I put force on model’s hands or not,lumbar force (L1-L5) is same.
Now,I really want professors help me to solve my questions.Thank you very much~

[melund (Morten Enemark Lund)]

Hi @Snow

Which version of the AnyBody Modeling System / Model Repository do you use?

High muscle activities usually indicate that the model is too weak and you may need to adjust the strength. However, that is not going to fundamentally change your results, only the absolute value of the muscle activities.

If you observe that the Center of Pressure (Plantar pressure), is in the wrong location that is a important place to look for errors. Maybe the ground reaction forces are not applied correctly to the model. Center of presure is given solely by the force plate data, so if that is incorrect maybe your C3D file has some issues. You can try to load the data in a program like Mokka and see if the forces look reasonable there.

Whether I put force on model’s hands or not,lumbar force (L1-L5) is same.

That sounds a bit weird. Maybe you forgot to include the forces class in the inverse dynamic study. See this topics: Using time in AnyFunInterpol for external forces in MoCap model

Best wishes,