Here is another tool that lets you use resistance to get fit. The Body Sculpture Aerobic Suspension Trainer is a full body trainer with variable resistance levels and an adaptable design to allow you to try a variety of exercises. It supports rotational moves to target core muscles.
The Aerobic Suspension Trainer can be hooked up to any overhead structure. You can use it to build a stronger core and more flexible body. The nylon straps for legs and arms let you try a wide variety of exercises.