A home gym system (100) is provided for performing weight lifting exercises with a load resistance (160, 164) coupled to a cable (132). The home gym system (100) includes a main frame (110) to which is pivotedly coupled at least one extension frame (120). A guide arm assembly (130) is slidingly coupled to frame extension (120) and vertically displaceable thereon. Vertical displacement of guide arm assembly (130) is made substantially effortless by a counter weight system (140) coupled to guide arm assembly (130) by a flexible member (141). Counter weight system (140) includes a floating pulley system (145) to compensate for changes in cable path length which result from the vertical displacement of guide arm assembly (130). Additionally, guide arm assembly (130) includes a system for increasing the load resistance by varying the mechanical advantage of the cable system. The change in mechanical advantage is accomplished by coupling the releasable coupling (192) at the exit end of cable (132) to the pivotable arm member (172) allowing the cable to be withdrawn from guide arm assembly (130) by displacement of both the exit end of cable (132) and a portion of cable (132) from a position intermediate a first pulley assembly (134) by a second pulley assembly (136), when pivotal arm member (172) is displaced.