The control code in the device behaves by creating an internal estimate of the subject's current position and then coordinating the motion of the four actuated degrees of freedom to take the desired motion. The desired motion is specified through an attached user interface that can be used by the patient or a therapist. The device can currently stand from a seated position, walk, and turn and sit down. In actual operation the device is triggered by one of two modes. The first mode is used early in training where the therapist manually triggers the steps of the user using the graphical interface; for advanced users, the machine interprets their motions to determine when steps are desired and the therapist is only responsible for starting and stopping the motion.