You've probably heard it before, but you really don't have to do another crunch. (No, really -- don't. They're bad for your posture, among a host of other ills.) Instead, use these exercises to firm, flatten, and contour your waistline by training your abs, obliques, and back muscles to resist bending motions and stabilize your core, which is what they're designed to do.
Perform 12 reps of each move, moving from one to the next with as little rest as you can handle (hey, I said they weren't crunches -- not that they were easy). Take a minute break between circuits, and do three sets total.
Come down on your right knee (like you're going to propose), holding a 5- to 10-pound dumbbell with both hands to the outside of your right hip (A). In one fluid motion, raise the dumbbell across your body and up to the ceiling, just past the outside of your bent-up knee (B). (Turn your head to "watch" the weight as it goes up.) Resist gravity as you lower the weight in the same trajectory back to the start position. Do 6 reps on one side, and then switch to do 6 reps on the other side.
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It wouldn't be a core workout without at least one plank. This variation brings you to your forearms (A), but adds the stabilization challenge of keeping your hips level and low while you take turns tapping one foot out to the side then back to center (B). A tap to each side and back to center represents one rep.
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Lie on your back with your knees bent, holding that 5- to 10-pound dumbbell in both hands, straight up above your chest (A). Keeping your arms as straight as possible, lower them out to one side, going only as low as you can control without your torso contorting (B). Keep your back flat as you bring the weight back to center, and then over to the opposite side (C). That's one rep.
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Begin standing with feet in a slight staggered stance, shifting your weight into the foot that's in front. Raise the opposite arm into the air and place the other hand on your hip (A). Slowly hinge forward, raising the back leg and lowering the torso, keeping the straight arm and leg in the same plane (B). (Use your hip-resting hand to remind you to keep your pelvis parallel to the ground.) With control, tilt your body back to the start position, tapping the back toes down only if you must. Do 6 reps on once side, then switch sides for the other 6.
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And ... plank No. 2! Align yourself into that forearm position as before, feet close together (A). Using your upper body and your toes, glide yourself forward several inches (B), then back the same amount (C). Keep those hips perfectly level the whole time. One to-and-fro is a rep.
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Lie on your back with your knees bent, with your heels close to your glutes (A). Press your hips high and hold 'em there (B), then raise a leg straight out so your knees are aligned (C). Lower the first leg (keep those hips up!), then raise the other. Repeat each pair 12 times.
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