The Ab Coaster is a revolutionary abdominal training device that provides a bottom-up workout for your abs.The revolutionary Ab Coaster puts you on the fast track to great abs. . Rather than working your ab muscles from the top down, the Ab Coaster works from the bottom up, helping you target those hard-to-reach lower abs. Just kneel on the comfortable carriage and pull your knees up. As you lift, the knee carriage glides along the biometrically designed curved track, engaging your lower abs first then the middle & upper region, giving a complete abdominal workout.