Although many people don't enjoy it, no one would ever tell you that abdominal work is not important. If you want a strong body, you need a strong center. 
Chances are high you want to make every bit of your abdominal workout count so to make your crunches most effective you need to move them onto a ball. A recent study ranked traditional crunches as the 11th most effective abdominal exercise, but ranked crunches on an exercise ball the most effective. Crunching on the ball made the abs work 24 to 38 percent more. And in this case more is good! To balance on the unstable surface of the ball, your core is stimulated to recruit more muscle fibers.
If you are new to using an exercise ball for ab work, to get some important details read more.
Ab Crunch on a Ball:
- Sit on a well-inflated and anti-burst exercise ball. Size wise, you should be able to sit on an exercise ball with your hips and knees both bent to 90 degree angles (here is more on ball size).
- Place your hands behind your head, and walk your feet away from the ball so you start to roll your torso onto the ball. The ball should support your hips and the curve of your lower back. Your legs should form a bridge with your knees bent at right angles.
- Exhale and lift your upper body by about 45 degrees, pulling the deep abs in toward the spine and return to starting position.
So get on the ball already!
I miss my exercise ball.