... Fitness Dominal Massage Machine Model: LJJ-509C (HOT SELLING)Product size:748*602*704mmMaterial:steel,foam,PU wheel,plastic parts G. ... , digital sit-up counter, Balance Ball, AbPal Exercise Machine With CE The traditional crunch starts with a jerking motion, which causes ... , which works your lower back muscles and the "back" of the core. 2012 Newest AB series--Back extension machine as seen on TV