A system for positioning a user support of an exercise device, including a user support having a user support surface; a pair of positioning members connected to the user support, each positioning member extending outwardly from opposite sides of the user support and being substantially aligned along a common axis; a frame configured for supporting exercise weights and including a pair of spaced apart portions, the spacing between the spaced apart portions of the frame defining a space configured for receiving the user support; and a guide located on each of the spaced apart portions of the frame, each guide defining a plurality of receivers each of which is configured for receiving a portion of one of the positioning members, with the guides each located such that the receivers of each guide are in substantial registry with one another, wherein the user support is adjustably and incrementally positionable relative to the frame by selectively positioning the positioning members so that they are received by the receivers to effect selective positioning of the user support relative to the frame.