1. A method for animating a character with muscle deformation responsive to kinematic motion and a physical model, the method comprising the steps of: estimating a first set of estimated joint torques from the kinematic motion and the physical model, said first set of estimated joint torques comprising an artificial load; determining, responsive to the artificial load, an external load; applying the external load to the physical model to produce a loaded physical model; estimating a second set of estimated joint torques from the kinematic motion and the loaded physical model; determining muscle activations from the second set of estimated joint torques; and animating the character with muscle deformation responsive to the muscle activations.