About Hill-type muscle model

[Bo Ding]

Hi all,

I have read that the muscle contraction force calculated by the Hill-type muscle model was comprised of two parts,
the active force and the passive force. But i feel confused that when the passive force will happen? Does it happen when i actively contract my muscles? If it does not happen, it must be true that the mucle fiber length will never reach the optimal value when doing active contraction, since if it reached the optimal muscle fiber length, the passive muscle force will happen according to the Hill-type muscle equations.

Thanks
Bo Ding

[Dimitar Stanev]

Hi Bo,

The passive force actually has an effect when the muscle length exceeds a certain level to prevent tearing of the muscle. The activation part scales the the active force.

Jim
BR