Gwen Stefani’s trainer, Gunnar Peterson, says that she gets her abs with the help of intense (but not lengthy) workouts. "Focus on cardio that uses your whole body to challenge more muscles and burn extra calories in less time," said Peterson, who is a fan of rowing. "It's easy on joints and works every muscle."
Rock-Star Abs Of Grammy Favorites
Find out how these performers train to flaunt belly-baring fashion.