Abstract: An exercise machine includes a frame designed to rest upon a floor surface; a back rest mounted on the frame; and a foot platform mounted on the frame. At least one of the foot platform and the back rest is movably mounted on the frame in such a manner that a person may rest his back against the back rest and exercise his quadriceps muscles in isolated, closed chain fashion. A resistance device is preferably provided to resist an increase in distance between the user's hips and the user's feet due to straightening of the user's legs at the knees.

Abstract: A multipurpose exercising apparatus. The apparatus includes a mattress unit formed of a back mattress and a seat mattress, a rack, and a damping unit, wherein the relative angle between the back mattress and the seat mattress being adjustable. The position of the mattress unit is adjustable relative to the rack. The damping unit includes at least one actuating bar, one linking mechanism and one damping force source. By changing the position and/or direction of the mattress, the angle between the back mattress and the seat mattress, and/or the position of the actuating bar, the user can operate the exercising apparatus to exercise different parts of the body in different exercising positions.