$ 97 ( 7- POUND BALL), THEGRAVITYBALL.COM
The 7- pound Gravity Ball ( also comes in 5 and 9 pounds) has become a trusty training companion. The ball attaches to one hand or foot ( or both), either with adjustable Velcro straps, fixed- length loop straps, or four anchor points. This allows smooth, grip- free calisthenics, with exercises ranging from leg lifts, to shoulder openers and strengtheners, to wrist rotations. As a rehab tool, rest-day cross- trainer, and ab strengthener— try it with crunches, leg lifts, and Russian twists— this unique device has endless potential.