Lie supine (on your back) with your legs bent and your feet flat on the ground.
Place your hands lightly either behind or by the sides of your head, keeping your elbows out.
Execution
Keeping your lower back flat on the floor, raise your head and shoulders a few inches off the ground by flexing your abdomen. Exhale as you do so.
Hold the contracted position for a count of two.
Inhale as you lower your head and shoulders to the starting position.
Repeat.
Comments and tips
Keep the movement slow and controlled. Don’t use momentum.
Keep your neck straight.
To make the crunch more difficult, stretch your arms out overhead and cross your palms. You can also hold a plate behind your head, or perform the exercise on a decline bench.
To make the exercise easier, cross your arms over your chest.
The crunch is not an effective ab exercise. In a classic study by the American Council on Exercise (ACE), many other exercises were found to be much more effective at working the abs and obliques than the crunch. The most effective exercises for the abs and obliques were found to be the captain’s chair (which is essentially the same as the hanging leg and hip raise) and the bicycle crunch. That’s why these exercises can be found in the training programs on this website.