I'm always looking for new ways to make the strength training moves I do at home more challenging, and it looks like Jennifer Lopez found the perfect piece of equipment. With her trainer, Gunnar Peterson, she uses a TRZ Suspension Trainer ($170), which weighs less than two pounds. All you do is attach it to a door, tree branch, swing set, or any other sturdy point such as a pull-up bar. Jennifer uses it to target her upper body, lower body, back, and abs.

Suspension training allows you to use your own body weight to create resistance, and many of the moves involve your torso, so it allows you to build amazing core strength. I've tried a TRX class before, and it was definitely a tough and sweaty workout, so if you have the dough, you can spring for a TRX Kit. It includes a DVD so you can learn all the moves and do a routine at home.