How to do crunches

2. Place your hands behind your head so your thumbs are behind your ears.

    Don’t lace your fingers together.

3. Hold your elbows out to the sides but rounded slightly in.

Tilt your chin slightly, leaving a few inches of space between your chin and your chest.

4. Tilt your chin slightly, leaving a few inches of space between your chin and your chest.

5. Gently pull your abdominals inward.

6. Curl up and forward so that your head, neck, and shoulder blades lift off the floor.

7. Hold for a moment at the top of the movement and then lower slowly back down.

* Keep your abdominals pulled in so you feel more tension in your abs and so you don’t overarch your lower back.

* Don’t pull on your neck with your hands or draw your elbows in.

* Do curl as well as lift. In other words, don’t yank your head, neck, and shoulder blades off the floor; you also need to curl forward, as if you’re doubling over. Think of bringing your ribs to your pelvis and exhale as you crunch up; inhale as you lower back down, keeping your belly button drawn in.

* Perform crunches very slowly and with control, doing 12 reps.

Gym alternative: Ball crunch

You can use a large plastic exercise ball (sometimes called a physioball) as an alternative to the basic crunch described above. Follow these steps:

1. Sit on a physioball and roll your torso down so that your back — from your shoulder blades down to your tailbone — is resting on the curve of the ball and your head, neck, and shoulders are above the ball.

Your knees are bent, and your feet are planted on the floor, hip-width apart.

2. Perform the same abdominal curling movement as you do for the basic crunch.

You have to move slowly and keep your abdominal muscles fully engaged to keep yourself from wiggling around on the ball or rolling off of it.