THEY claim to tone muscles while you sit or stand, but are electronic muscle stimulation (EMS) devices like Slendertone really an adequate replacement for time at the gym? In a study at the University of Wisconsin that was conducted on behalf of the American Council on exercise, the physiologist Dr John Pocari found that, in terms of buttock strength and gluteal endurance, regular use of Slendertone was as effective as performing the quadruped hip extension exercise. However, Pocari points out that the EMS devices only target one area, so you’d still be better off exercising.