Abs of Steel Amp up your abs routine by adding a little extra weight! You'll force your muscles to work even harder to help stabilize your trunk while performing moves that closely mimic everyday activities (climbing a ladder, holding onto objects while sitting up in bed, or reaching for the top shelf in your closet). Plus, the extra effort required to move that additional weight means you'll burn more calories and flatten your stomach faster. So grab a set of dumbbells and give this workout a go! How it works: Do 1 set of the prescribed number of reps for each exercise, moving from one to the next with little to no rest in between. Do the full circuit 1 to 3 times, depending on how much time you have. It's great after a cardio session, during a strength workout, or on its own for a killer core workout. You'll need: A set of dumbbells heavy enough to challenge you by the final rep of each set (5 to 10 pounds, depending on level); you may want a mat or towel for the floor work. Windmill Stand with feet slightly wider than hip width, knees bent, holding one dumbbell in front of chest with both hands, elbows bent. Lower into a squat as you rotate your torso to the left and straighten both arms, reaching right hand to the floor and left hand (holding the dumbbell) to the ceiling. Llook up at top hand. Maintaining upper-body position, raise halfway up out of squat (think of pressing up with the left side of torso), and then lower back to touch the floor with right hand. Return to start. That's one rep. Do 15 reps, and then repeat on opposite side. Single-Side Vertical Climb Grab a pair of dumbbells and stand on right leg with left toe pointed out to the side, lightly touching the floor. Bend right arm, bringing dumbbell to just outside of shoulder, and extend left arm up, palm facing forward. Press right arm overhead and bend left elbow as left knee lifts up toward chest. You should feel your left obliques working to lift knee as high as possible. Return to start. Do 15 reps, and then repeat on opposite side. Bow-and-Arrow Squat Pull Grab a pair of dumbbells and get into squat position, hinging forward at hips, lowering chest, and reaching arms to the floor. Bend knees a little deeper and open arms into a "bow and arrow" by reaching right arm to the ground and bending left elbow back behind body, twisting torso slightly to the left during the pulling action. Immediately switch sides, rising slightly up out of squat as arms change position, lowering back into squat as right elbow bends back and left arm extends. Do 20 reps, alternating sides each time. Plank Pull Through Begin in a full plank position with a dumbbell on the floor a few inches away from the outside of right hand. Engage abs to keep torso steady and reach left arm under right to grab dumbbell. Pull the dumbbell across the floor to the left side of body, releasing it just outside of left arm, and then return to plank. That's one rep. Do 20 reps, alternating sides each time. Straight-Arm Climb Grab a pair of dumbbells and lie faceup on the floor, arms extended straight out above chest, palms facing away from head. Lift head and neck off the floor, looking up to ceiling, and press right arm up, lifting head and right shoulder blade off the floor. Immediately lower right shoulder and repeat the lift on left side. Avoid letting elbows bend as you lift and lower. Do 20 reps, alternating sides each time. Single-Arm Sit-Up Grab a dumbbell in left hand and lie faceup on the floor, left arm extended straight out from shoulder, right arm by side on the floor. Extend right leg out straight and bend left knee, placing left foot flat on the floor. Brace abs in tight and roll up through spine (keep left arm reaching straight up to ceiling the entire time). Reach right arm forward in front of shoulder. Round back and brace abs in tight to slowly roll through back and return to start. Do 15 reps, and then repeat on opposite side. Too tough? Keep right arm on the ground for more support as you do the sit-up and lower down. Source