An adjustable exercise machine for performing resistance exercises comprises a base and an upper frame including front and back end stationary exercise platforms, and a movable exercise platform that reciprocates between the stationary platforms. A plurality of biasing members is selectable by an exerciser via selector knobs to generate a bias force against the movable platform. A plurality of pivotable lift supports are connected between the base and the upper frame. Front and back actuators are connected between the base and the lift supports by lifting yokes to selectively raise and lower the front and back ends of the machine. The movable platform may be connected to move along the exercise machine by trolley wheel assemblies. A plurality of travel limit decelerators mounted on the rails engage and rapidly decelerates the movable platform as it reaches its limits of travel on the rails.