Watch the video below to see a demonstration of proper form and technique for the crunch exercise. You can also check out some more abs exercise videos or find exercises for other muscle groups.
To perform a set of crunch:
Lie supine on a mat with your knees bent, feet on the ground and hands beside your ears. The trunk should be in a neutral position.
Squeeze your abdominals to raise your chest and head straight off the ground until your shoulder blades lose contact with the mat. It is important to breathe normally and maintain a neutral lower back position throughout the entire movement.
Pause at the top position for a 1sec count while squeezing your abdominals.
Lower your chest and head back to the ground without losing the neutral postion of your lower back. Remember to breathe normally throughout the entire movement.
Repeat steps 1 through 4 until you have completed the desired number of crunch repetitions before resting.
This completes one set of crunch.