The crunch is the most basic exercise you can do when training your abs. Lie on your back with your feet flat on the floor (put your toes under a bench or weight plate for stability). Place your arms either behind your head (not with your fingers interlaced, as that makes it easier for addition strain to be placed on the neck), or across your chest. Slowly contract the abdominal muscles, concentrating intently on the muscles being worked. Pretend you’re holding a tennis ball under your chin in order to avoid tilting the head forward and injuring your neck. Stop when your body is approximately 30 to 40 degrees off the floor, going any farther than this works your hip flexors more than your abs. At the top of the movement, crunch as tightly as you can for one count, then slowly lower yourself back down – try to take no less than two seconds to return to the starting position. That’s one repetition.
For a more complete crunch, try to exhale on the way up and inhale on the way down. This empties the lungs of air and allows the abdominals to perform a more complete contraction.
The Swiss Ball Crunch
This is a more advanced form of the basic crunch. A Swiss ball is a large, air-filled ball that helps to stimulate your abs by increasing the range of motion used in exercises.
To do a Swiss ball crunch, sit down on the ball with both feet on the ground in front of you. Now walk your feet forward until you’re balancing on your back, with your legs bent 90 degrees at the knees. From here, simply perform the crunch as normal. For more resistance, move so that the balance is resting slightly lower in your back – this will facilitate a steeper angle in the crunches.
You can add more resistance to either of the above crunches by holding a weight plate (or medicine ball) on your chest while performing the exercise.