After giving birth to twins Max and Emme (who turn 2 on Feb. 22), Jennifer Lopez got back in shape by preparing for the Nautica Malibu Triathlon in Sept. 2008. Setting a goal was the key for the actress and singer, who began an intense six-day-a-week regimen of running, swimming and biking for a total for two hours. Recently, the singer has been working out with trainer Gunnar Peterson up to three times a week and when she's traveling, the celeb fitness guru sends her workouts via email for her to maintain. But the mom of two told the January issue of Allure that she's dialed down the uber-intense workouts she once did. "I'm not the monster I used to be in the exercise department," she said. Want to follow J.Lo's lead? Signing up for a half-marathon or race is a great way to challenge yourself to get in shape. When you cross that finish line, you'll feel like a winner, too!