Abstract: A crank including a mechanism capable of connecting the crank arm to a shaft to drive the shaft in rotation in either a unidirectional drive mode or a bidirectionally driving mode, the mechanism being quickly adjustable between modes. A coupler in the mechanism may be slidable between a first position engaging the crank arm with a hub portion fixedly mounted on the shaft and a second position in which a unidirectional clutch can operate to allow rotation of the crank arm freely about the shaft in one direction but cause rotation of the shaft in the opposition direction. The coupler may be arranged to be coupled only when the shaft is in a selected angular position.

Abstract: An exercise machine and a method for its use in training selected muscle groups by controlled use of brakes to resist crank movement adjustably at specific and adjustable controlled positions in the rotation of a crank. A control system may be incorporated to cause brake mechanisms to apply varying amounts of resistance to a pair of pedal-driven cranks to simulate the efforts required to ride an actual bicycle over a course including various upslopes and down-slopes.

Abstract: The system includes a flexible button top which has a sleeve appurtenance which is force-fitted over an externally helically grooved stud assembly having an integral self-adhesive back mounting plate. The button top is flexible enough so that it can be applied to, and removed from the stud assembly without the use of a tool, yet it is hard enough so that the stud will not perforate the flexible button top when impacted. The adhesive-backed stud assembly includes a helically threaded metallic screw perpendicularly attached to a metallic circular disc with a plastic foam backing impregnated with adhesive. The adhesive backing is covered by a release film prior to use. The adhesive-backed stud assembly can be applied without the use of a tool.