If you aretrying to build ab muscle (you can't zap fat from one area)you do sit ups BUT when you put your hands behind your ears you dont't clasp them together, just use them for support, and when you go up take 10 seconds and when you do down take 5 seconds. You will feel the burn after 1-3 situps the first time but you can get better. I love these becasue you can actually feel your muscles working because too many people go so fast doing muscle workouts they are actually just using momentum and not working their abs