Is there a EEF-Position to Muscle length Jacobian?

[Lukas Bildheim]

Hi,
I'm trying to build a controller for reaching movements, but my model requires a Jacobian that relates the change of the end effector speed (let's call it v) with the contraction speed of the muscles (call them s). So basically

J_ij = dv_i / ds_j

The closest I have gotten is using the Matter Subsystem to get the Frame Jacobian of the hand, but that relates the EEF speed to the joint angle velocities w. So my question is whether there is a function that does what I need and that I have overlooked or if there is something that relates muscle contraction speed with joint angle velocity so that I can do

J_ij = dv_i / dw_k * dw_k / ds_j

I suppose the first option is unlikely since as I understand it SimTK is unaware of the actuators, hence me asking here.

Thank you in advance.