ARX is safe for all forms of rehabilitation, offering the full spectrum of resistance ranging from passive resistance (stretching) all the way to eccentric loading (negatives). There are no weights to drop, the speed is pre-set and controllable, and the machine can never act upon the user without the user first acting on the machine. This means that a user can never encounter any level of force that they themselves did not first produce, and this never-excessive scenario dramatically lowers the risk of injury.