Patent ID: 7641599

Claim:
An exercise therapy device comprising: a rotatable pedal shaft pulley; pedals connected to the pedal shaft pulley for rotating the pedal shaft pulley upon application of a force to the pedals by a user using the exercise therapy device; a load motor coupled to the pedal shaft pulley for supplying an assisting force assisting the user in rotating the pedal shaft pulley; a transmission, including a load side pulley and an endless belt, coupling the load motor to the pedal shaft pulley and transmitting a driving force applied to the pedals by the user in rotating the pedal shaft pulley to the load motor, and transmitting the assisting force from the load motor to the pedal shaft pulley; a sag detector detecting sag in the endless belt and outputting a sag detection signal in response to detection of sag in the endless belt; and a load control device determining, in response to the sag detection signal, whether rotation of the pedal shaft pulley is being effected by the force applied by the user to the pedals or by an assisting force supplied by the load motor, and controlling the load motor by activating the load motor to produce an assisting force when the force applied by the user, in beginning rotation of the pedal shaft pulley, is rotating the pedal shaft pulley, and by stopping the load motor when the assisting force is turning the pedal shaft pulley so that the pedal shaft pulley rotates faster than the rotating speed of the pedal shaft pulley produced by the force applied to the pedals by the user.