Everybody wants a slender and toned middle, not only because it makes you feel good in a bathing suit, but also because it prevents back pain. Plain crunches are not the most effective exercise on their own, and to increase the level of intensity, you can add some weight to your ab work. That's where the Gaiam Abs Ball ($40) comes in.
It's similar to using a medicine ball, but the handy handles make it much easier to hold, so you can concentrate more on the exercise, rather than it slipping out of your palms. The ball weighs six pounds and it comes with a 35-minute instructional DVD to show you how to use it. Triathlete Jonathan Roche demonstrates how to define your obliques and abs with both beginner and advanced workouts. Adding a little weight to your upper body really helps to target and strengthen your core. If the 6-lb ball is too easy, you can buy the 8-lb Abs Ball instead.