Lay on your back with the exercise ball between both feet. Squeeze the ball and lift it with your legs to roll back and touch it to the ground behind your head. "Fifteen times will kick your ass," says MacMillan. Alternatively you can roll the ball in a giant circle with your legs, passing it above your head, and then reversing the direction.
Powered By ZergNet
The Brutal Charm of an NFL Hit Man
Plus: Jesse Ventura vs. the Navy Seals
ON NEWSSTANDS NOW
When to Say No to Your Doctor
Sign up to receive the Men’s Journal newsletter and special offers from MJ and its marketing partners.