I know that I can access the computed muscle activations after running inverse dynamics from the HDF5 file under the Path /Output/BodyModel/Left/Leg/Mus/{Muscle}. But what is the unit of those trajectories?
Are they dimensionless normalized muscle forces?
What must be done in order to obtain the forces in Newton?
It sounds like you are going the hard way.
Muscle activation is a current muscle force divided by the muscle strength (max force). Please revisit the tutorials: “Inverse Dynamics of Muscle Systems”