How to Do Crunches Properly

This popular variation works your rectus abdominis and external obliques, predominantly in the lower abdominal region.

1. Lie down on the floor with your knees bent and your feet planted hip-width apart.
2. Place your hands on the floor by your side.
3. Inhale, contract your abs towards your spine.
4. Exhale and lift your feet off the floor and raise your knees upwards and inwards towards your chest, keeping your knees at a 90 degree angle. Your hips should tilt inwards to crunch your abs.
5. Slowly lower your feet to the floor.

A bicycle crunch fires up your transversus abdominis, the deepest of the abdominal muscles. This is considered one of the key muscles to prevent back pain.

1. Lie down on the floor with your knees bent and your feet planted hip-width apart.
2. Place your hands gently on your head with your elbows out wide, with your fingers grazing your ears.
3. Lift one leg off the ground and straighten it outwards, raising the opposite knee upwards towards your chest.
4. Lift your chest upwards and turn your torso—opposite elbow to opposite knee.
5. Lower back to a neutral position with your knees raised.
6. Switch to the other side—opposite elbow and opposite knee.

A medicine ball variation can increase the intensity of a traditional crunch and fire up your obliques.

1. Sit on the floor and raise your feet off the floor. Straighten your legs with a slight bend in the knee.
2. Hold your medicine ball in front of your hips and lean back to a 45-degree angle.
3. Move the ball from the left-right, twisting your torso and contracting your obliques.

The slower and more controlled your crunches are, the better ab activation you'll get. That's because you're increasing the time under tension. A single crunch should last a few seconds, performed in a controlled manner. Aim for around two seconds in the concentric phase (when you lift shoulders up) and two seconds in the eccentric phase (when you lower).

A common complaint from crunches is neck pain. This is a sign you're not practising proper form. Avoid neck pain by keeping your gaze ahead and neutral and tucking your chin towards your chest. This position reduces the activation of the hyoid muscles, which are the stabilising muscles that run from your chin to your collarbone. You want to be putting the responsibility of stabilisation back into the abdominals.

Remember, crunches are not sit-ups! You don't want to lift your entire upper body when coming up. This is a small movement. In fact, the smaller the movement, the more difficult it becomes as you don't build up momentum. Aim to raise your shoulder blades just a few inches from the ground.

The concentric phase of a crunch has two parts: you want to curl and lift your shoulders from the ground to come up. If you just curl your shoulders, you're not getting the elevation and you won't target your abdomen fully. If you struggle to feel the burn when you crunch, this might be your issue. Visualise bringing your ribs to your pelvis on the exhale as you curl and lift upwards.

Here's the truth: Your arms have nothing to do with crunches. Crunches are an abdominal isolation exercise. Your arms can be in any position you choose—whether that's across your body, out to the side or tilting inwards. Choose a position that is comfortable for you and that allows you to focus on the mind-muscle connection with your abs, not your arms.