Abstract: A passive programmable resistance device uses a closed loop feedback for controlling resistance to rotational or translational motion of an object. One or more actual parameters, such as force or position, are measured and compared with desired parameters. The differences are used to provide a control signal which controls the resistance to the movement of the object.

Abstract: An exerciser bar is supported for rotation and acts against an hydraulic cylinder with the angle of the bar and the pressure in the cylinder measured and fed to a micro computer which, using this input data, controls the cylinder pressure in accordance with a selected exercise program, the micro computer also providing outputs to displays so that the person exercising can monitor his progress.

Abstract: An improved exercising device for exercising the legs of a user includes a frame member with a lever arm having one end pivotably attached thereto. The lever arm extends downwardly from the portion of the frame member to which it is pivotably connected, and a pair of foot-engaging force transfering members are mounted on the lower end of the lever arm. A cable has one end pivotably connected near the lower end of the lever arm, passes around an eccentrically mounted pulley and has its other end connected to weights. As the user lifts the lower portions of his legs, the lever arm is pivoted to pull the cable and the weights attached thereto, thereby strengthening the knee muscles of the user. The eccentrically mounted pulley varies the resistance to movement of the user's lower legs initially increasing the resistance and then decreasing the resistance in a sinusoidal manner as the lower legs are lifted to pivot the lever arm and lift the weights.