A prosthesis (1) or an orthosis and method of operating the same. The prosthesis or orthosis comprising a moveable component (2), a motor (7) operable to move the component, wherein the motor has at least one operating parameter, the application of which to the motor results in the component having at least one operating condition; and an electronic device (28) operable to: determine at least one operating parameter of the motor and determine at least one instantaneous operating condition of the component from a predetermined operating profile of the motor and component and the determined at least one operating parameter of the motor, the predetermined operating profile of the motor and component being based on one or more operating parameter inputs to the motor and one or more resulting operating condition outputs of the component.