Flat Belly Fast—No Crunches! Four moves that guarantee you'll get abs in six weeks Hold a dumbbell in your right hand, bend your knees, and lean forward from your hips (a). Brace your abs and pull the weight up to chest height without rotating your torso (b). Return to start. That's one rep. Do two sets of each move (eight to 10 reps per side) three days a week to streamline your silhouette fast.