Abstract: The present invention relates to a system for rehabilitating an ankle in which a mobile platform receives a patient's foot. The mobile platform can be moved in six degrees of freedom. The position and orientation of the mobile platform is measured in relation to the fixed platform in six degrees of freedom. The force exerted by the foot against the mobile platform is measured in six degrees of freedom. The measured position and measured force are forwarded to an electronic interface and fed to a programmable computer. The programmable computer determines desired force feedback to be applied by the controller interface to the mobile platform. The desired feedback signal moves the mobile platform to a desired position or applies a desired force or torque to the mobile platform. The rehabilitation system can include simulation of virtual objects which can be moved by the user to simulate an exercise. For example, the virtual reality simulation can include exercises for balance, flexibility and strength.