1. A method for animating a character with muscle deformation responsive to kinematic motion and a physical model, the method comprising one or more processors performing the steps of: obtaining the kinematic motion and the physical model; estimating a first set of estimated joint torques from the obtained kinematic motion and the physical model, said first set of estimated joint torques comprising an artificial load; determining an external load corresponding to the artificial load; apply the external load to the obtained physical model to produce a loaded physical model; estimate a second set of estimated joint torques from the obtained kinematic motion and the loaded physical model without modifying the obtained kinematic motion; determining muscle activations from the second set of estimated joint torques; and animating the character with muscle deformation responsive to the muscle activations.