Would be similar to the typical simulations of humanoids. If you need to model the deformations of the human body, or get a proper model of tendons that make up humans, it'll be more difficult, but possible.

Proper simulators for those exist, you essentially need an engine with a compliant contact model. MuJoCo is the goto here, see:

https://mujoco.readthedocs.io/en/stable/modeling.html#muscle... https://mujoco.readthedocs.io/en/stable/computation/fluid.ht...

These explicitly model biological muscles. IIRC it was originally created to model human hands (I could be misremembering though).

Really depends on the fidelity you want.

Edit: I also work in rigid body simulation for robotics.