Use the ab wheel to sculpt a strong core.
The ab wheel is a simple, but effective piece of gym equipment. It consists of a wheel with a long handle running through the center. This allows you to hold the handles on either side while the wheel rotates. Two types of ab wheel are available. Single ab wheels have just one wheel, while dual ab wheels have two wheels placed side by side.
Getting the Form Right
Technique doesn't change whether you're using the single or dual ab wheel. The basic variation of the exercise is the kneeling rollout. Kneel on a mat, grasp the handle with one hand one each side of the wheel and then roll forward by pivoting on your knees. Keep your arms straight and your back flat and use your core muscles to control the movement.
A Matter of Stability
The only real difference you'll find between a dual and single ab wheel is how stable it feels. The two wheels on the dual version make the roller run slightly more smoothly, while the single wheel version is more likely to veer off course. For beginners, this may mean that the dual wheel is a better option as you get to grips with the technique, allowing you to focus on building up the initial strength you'll need to progress. The instability of the single wheel makes this version a little more difficult, thus making the move more taxing on your core and shoulder stabilizing muscles. It may be too much for beginners, and you might be unable to use the correct form.
The Cost Factor
Price varies depending on where you purchase your ab wheel, but dual wheels are generally a little more expensive. While ab wheels are a relatively inexpensive addition to your array of gym equipment, if price is a consideration, opt for a single wheel. In "Never Gymless," strength coach Ross Enamait advises that a cheap, basic ab roller will do a perfectly adequate job when kitting out a home gym.
Try easier rollout variations first -- such as Swiss-ball rollouts -- before attempting ab-wheel rollouts, advises Jay DeMayo, strength and conditioning coach at the University of Richmond. After you've mastered Swiss-ball rollouts, try rollouts on a suspension system, then on a barbell and finally the wheel. When picking your wheel, remember that very little difference exists between dual and single ab wheels, so try before you buy and get the one that you find most comfortable.