The crunch exercise is the backbone of abdominal training. It develops the muscles of the abs to help you build that much-desired six-pack. But did you know that there is a way to do crunches that can actually decrease the size of your waist?

The key to this technique is the top position of the crunch where your abdominals are contracted as hard as they are able to.

When you're in this top position, I want you to breathe in and out slowly a few times. Try to relax every other muscle except the abs. This breathing in and out will intensify the contraction (as you will find out very rapidly).

Here's how it works:

The muscles of the abdomen are arranged in layers around your midsection, similar in concept to the rings in a tree. While you are contracting the rectus abdominus (the top-most front layer of your abs, also known as your six-pack) continuously, the deeper abdominal muscle fibers are relaxing and contracting each time you breathe.

Each time the deep fibers relax, your rectus abdominus (because it is contracting so hard) will squeeze them in a little more, making your waist-area a little smaller and tighter.

The reason this works to decrease the size of your waist is simple. Usually, most people's abdominal muscles just kind of sit there. They don't stay tight, therefore your midsection tends to slouch forward and outward.

This technique teaches your abdominals to maintain a degree of tightness and tone in them even when you are relaxed. This keeps your abs in, leading to a visually smaller waist.

For more information on how to properly execute the Abdominal Crunch, click here.