The Pilates trainer-to-the-stars, Mari Winsor owns and operates two Pilates studios in the Los Angeles area. She has been featured in Allure, Redbook, Elle, LA Magazine, Health & Fitness, USA Today, Fitness, Shape, In Style, Vogue, and Time and has appeared on MTV, Access Hollywood, and Entertainment Tonight. She is the author of The Pilates Workout Journal and The Pilates Powerhouse, for which she appeared on the Oprah Winfrey show. Mark Laska is a professional writer and publicist and co-author of The Pilates Powerhouse and Body-Fat Breakthru! He lives in Los Angeles.