Muscle Release/Hill Model - Only active force remaining?

Hi,

I’d like to simulate a muscle release for the subscapularis, where I release the superior tubular tendon. This would be the two superior insertion for the muscle (subscapularis node 1&2). I assume that cutting the tendon would only leave the active and passive muscle force and the passive force (seriell spring element in hill model) would be cut off. So my approach is setting Ftbar eq. 0.0001 as a released tendon cannot exert any force.

Assumption sounds reasonable? :rolleyes:

Thanks
Hauke

Hi Hauke,

In the 3E muscle model, the force in the tendon is equal with the sum of the force in the active part and the passive part. So if you want the passive force to be zero, then the force in the active part is equal with the force in the tendon, which is in series with the muscle fibers.
So if you want the contribution of the parallel elastic component (the passive force) to be very small, I would recommend to change the parameter PEFactor to a high number.

Greetings, Mark

I meant the force of the tendon. This force should be zero, as you release the tendon.

If you want to have the tendon force to be zero that you have to make sure that both the force in the contractile element and the force in the parallel elastic component are zero.
That can be done by changing the muscle parameter F0 to zero and to change the parameter PEFactor to a high number for that particular muscle.
Does that answer your question?