Boot Camp

Trainer David Kirsch works with stars like Heidi Klum, Liv Tyler, Jimmy Fallon and Kerry Washington and his sessions are incredibly brutal. (Trust us, we've tried one.) But they also come with great payoff. He tells us you should definitely think about the shape of your dress when planning your workouts and focus on either the upper or lower body accordingly. "For an upper body focus, I suggest moves like shadow-boxing and push-ups," advises David. "For lower body, I suggest doing sumo lnges and plie toe squats." You can find even more tips in his Abs & Arms and Butt books.