The World’s Greatest Abs Exercise

Walk into any gym in any city, and you’ll see the same thing: Lots of men and women doing lots of reps of exactly one abs exercise: the crunch. This classic move is excellent for increasing the size of your midsection muscles, but it comes with an inherent drawback: To do it, you must round your lower back. Repeatedly. And that repetition increases the strain on your intervertebral discs and the wear and tear on your spine, setting the stage for back pain down the road (or exacerbating any damage that already exists).

That’s why, at Men’s Health and Women’s Health, we advise our readers to sculpt their stomachs with a different move: The McGill Curlup (named after Stuart McGill, Ph.D., who popularized the exercise and is widely regarded as the world’s top spinal researcher). While this exercise looks like a crunch, it doesn’t act like one. That’s because it forces you to work your entire core while keeping your spine in a natural “S-curve” alignment. As a result, it minimizes the stress on your spine while strengthening its supporting musculature, allowing you to build a rock-solid 6-pack without breaking your back.

See below for detailed instructions. Perform four to five repetitions, rest for 30 to 60 seconds, and repeat one or two more times. To make it even harder, raise your elbows off the floor as you curl up.

• Lie on your back with your left leg straight and flat on the floor. Your right knee should be bent, and your right foot flat.

• Place your hands palms down on the floor underneath the natural arch in your lower back, and maintain that arch for the duration of the move.

• Slowly raise your head and shoulders off of the floor without bending your lower back or spine, and hold this position for seven to eight seconds, breathing deeply the entire time. That's one repetition.

• Once you’ve completed all of your repetitions, rest for 30 to 60 seconds, and then switch legs (so that your right leg is straight and your left leg is bent) and repeat the exercise.

Like this exercise? For full-color photos and explanations of 600 more, along with tons of workouts and expert fitness advice, check out this comprehensive collection.

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