Muscle-tendon model with length-history dependent activation-velocity coupling

We developed and evaluated muscle-tendon models incorporating Hill-type structure and length dependent coupling between activation and velocity. Model parameters were estimated from experimental data collected during simultaneous modulation of length and stimulation inputs, and the isometric length-tension curve. A model with length-history dependent activation-velocity coupling predicted the behaviour of the muscle during random perturbations and during iso-velocity movements, including short range stiffness, post yield force drop, and steady force change following the force drop