"Oprah used to be not so crazy about weight training, but now she really enjoys it," he says. "I think she finds it a kind of meditation." Typically, this move would come toward the end of her workout. "The general rule is that you work the bigger muscle groups first—the legs and back—to warm them up," Greene explains, "then finish with the arms. That's especially important for beginners; there's more chance for injury if you start with the small muscles."