An exercise device includes a belt unit that has an element that encircles a swimmer's hips near the pelvis. The belt unit includes restraining straps that are attached to the element encircling the swimmer's hips by means of hook-and-loop material so the straps can be located in the most effective position on the swimmer. The device further includes an anchor that can be attached to a stationary device associated with the swimming pool and has rotatable rings that are attached to the restraining straps.