The 4 Best Exercises for Your Core That Aren't Crunches

Why do it: Michele Olson, PhD, a professor of exercise science at Auburn University, has found that dozens of moves (some familiar, some new) are better than crunches at working your core—without putting stress on your spine. How did she do it? She lab-tested ab exercises using an EMG machine to measure the strength of contractions. One of her favorites is the no-frills Pilates Hundred. This isometric exercise was 31 percent more effective than traditional crunches at targeting the external obliques (the V-shaped muscles running diagonally down your sides). The Hundreds are also uniquely effective at working the deeper ab muscles, Olson says, which support the spine.

Starting position: Lie on your back with your knees bent at 90 degrees, shins parallel to the floor (arms at your sides).

How to do it: Lift your head and shoulders. Inhale and pump your arms, palms facing down, 3 to 4 inches off the floor, 5 times. Exhale and pump your arms 5 more times. This is 1 breath cycle, or 1 rep. Repeat until you have completed 10 breath cycles.

Why do it: This advanced version of the classic "bird dog" is another terrific move for those deep abdominal muscles, which, Olson says, are practically neglected by crunches. And because this move strengthens the support muscles for your back, it can help improve your posture.

Starting position: On all fours, align your knees under your hips and your wrists under your shoulders.

How to do it: Raise your left arm in front of you to shoulder height and, at the same time, extend your right leg out behind you. Hold for 2 counts, then lower your left arm and right leg to the ground. Alternating sides, complete 15 to 20 reps total.

Why do it: Sure, this standing move works both your abs and your lats (the muscles that pull in your waist). But its real advantage over crunches is that it works the front and back muscles in harmony—a feat that, Olson says, helps you build overall core strength and makes you less likely to get injured when picking up heavy objects.

Starting position: Stand tall with feet hip-width apart and hands behind your head, elbows out.

How to do it: Tighten your abs and lean slightly forward as you bring your right knee up toward your belly button. Lower the right leg and return to start; repeat on opposite side for 1 rep. Alternate legs; do 12 reps total.

Why do it: This yoga-inspired move is a variation on the side plank, which Olson found is 47 percent better at working the external obliques on the sides of your body and slightly better at toning the rectus abdominus (those muscles that make the 6-pack).

Starting position: Sideways: Lie on your right side with your right forearm on the floor, your hips and legs stacked.

How to do it: Press into floor, straightening left arm upward and lifting hips toward ceiling. For stability and balance, bend your right knee so that your shin makes contact with the ground. Hold for a count of "one Mississippi," then lower. Lift again and repeat. Complete 15 reps on each side.