The exercise ball is an excellent tool to have in any home gym. Their popularity is a indicator of their effectiveness. Any number of exercises can be done of the ball, but most of them focus around core strength and abdominal muscles. If you don't have one already, consider making the purchase - they typically run from $10 to $20 a piece. The exercise ball crunch is one of the top 10 ways to flatten your abs, and really works your rectus abdominis.

Follow these steps to perform the exercise ball crunch correctly. It is important that you have good form and make sure that you follow these steps. Not doing so has two side effects - first, your workout wont be as effective, so you won't see as good results as you could be having. Second, and more importantly, you risk the chance of injuring yourself if you do exercises incorrectly. These 5 steps will detail how to properly perform the exercise ball crunch.

Step 1: Lie face-up on the ball, which should be resting under your mid to lower back.

Step 2: Either place your arms behind your head or cross them over your chest. If you place them behind your head, make sure not to use them to help pull your upper body into the crunch.

Step 3: Lift your torso off of the ball while contracting your abs. Pull the bottom of your ribcage toward your hips. This is kind of like a crunch.

Step 4: Don't let the ball roll, you need to keep yourself stable (this is part of the exercise - builds oblique muscles).

Step 5: Lower yourself slowly back down. Remember, the slower you go, the more benefit you get from the exercise. As you lower yourself, stretch out your abs. Repeat 12 - 16 times, for 2 - 3 sets.

The hardest part about the exercise ball crunch will probably be keeping the ball stable as you curl. However, this is not just busy work - it actually helps strengthen and tone your oblique abdominals (on the sides) and build your core strength. The first couple of times you use the ball you will probably feel awkward and like you are not getting much effect out of it, but just keeping sticking to it and it will soon become second nature.