Jimmy PenaJimmy PeNa, MS, received his master's degree in clinical exercise physiology from the University of Texas at Tyler in 1998. He then published his thesis summary on the effects of endurance training on muscle size and strength in competitive atletes in the renowned journal Medicine & Science in Sports & Exercise. PeNa served as the fitness director for Muscle & Fitness and Muscle & Fitness Hers magazines, and for more than a decade wrote and edited thousands of articles on training and fitness, making him one of the nation's most published fitness experts. In 2006, PeNa designed the women's training programs for LL Cool J's New York Times bestseller Platinum Workout, and later that year served as creator and host of the Muscle & Fitness DVD series, The Rock-Hard Challenge. In early 2007, PeNa began working with Mario Lopez, contributing to his book Knockout Fitness, while also helping prepare his physique for appearances in People, TV Guide, and on FX's acclaimed primetime show Nip/Tuck. PeNa is an ongoing resource for NBC's Extra and in 2010 was the coauthor of the New York Times bestseller, Extra Lean. Read More Read Less