Abstract: A stair exerciser apparatus for simulating stair climbing includes a frame, a lower shaft and an upper shaft mounted rotatably on the frame, a conveyor operatively engaged with the upper shaft and the lower shaft, a plurality of steps, a flywheel and a one-way clutch mechanism. The plurality of steps are joined to the conveyor for movement with the conveyor. The flywheel is operatively engaged with the conveyor. The one-way clutch mechanism is operatively engaged with the conveyor and the flywheel. The one-way clutch mechanism is configured to selectively couple the conveyor with the flywheel such that motion of the plurality of steps in a first step direction drives rotation of the flywheel when the one-way clutch mechanism is engaged, and the one-way clutch mechanism decouples the conveyor from the flywheel when the one-way clutch mechanism is disengaged.