An exercise device for use in weight training, body building, and the like, in which exertion against resistance is utilized to promote bodily development. The device has a training load with a plurality of individual weights, and the number of weights are selected by mechanical actuators controlled...http://www.google.es/patents/US5037089?utm_source=gb-gplus-sharePatente US5037089 - Exercise device having variable resistance capability
Exercise device having variable resistance capability
