About the Author Thomas W. Rowland, MD, is a pediatric cardiologist at Baystate Medical Center in Springfield, Massachusetts, and a professor of pediatrics at Tufts University School of Medicine. A graduate of the University of Michigan Medical School, Rowland is board certified in pediatrics and pediatric cardiology by the American Board of Pediatrics. Rowland, who has had more than 150 journal articles published, is the author of four books: Biologic Regulation of Physical Activity; Children’s Exercise Physiology, Second Edition; Tennisology: Inside the Science of Serves, Nerves, and On-Court Dominance; and The Athlete’s Clock. He has served as editor of the journal Pediatric Exercise Science and as president of the North American Society for Pediatric Exercise Medicine (NASPEM) and was on the board of trustees of the American College of Sports Medicine (ACSM). He is past president of the New England chapter of the ACSM and received the Honor Award from that organization in 1993. Rowland is a competitive tennis player and distance runner. He and his wife, Margot, reside in Longmeadow, Massachusetts. The American College of Sports Medicine (ACSM), founded in 1954, is the largest sports medicine and exercise science organization in the world. With more than 50,000 members and certified professionals worldwide, ACSM is dedicated to improving health through science, education, and medicine. ACSM members work in a wide range of medical specialties, allied health professions, and scientific disciplines. Members are committed to the diagnosis, treatment, and prevention of sport-related injuries and the advancement of the science of exercise. The ACSM promotes and integrates scientific research, education, and practical applications of sports medicine and exercise science to maintain and enhance physical performance, fitness, health, and quality of life. The North American Society for Pediatric Exercise Medicine (NASPEM), founded in 1985, is a professional organization whose membership is composed of medical doctors, researchers, educators, and students interested in pediatric exercise. NASPEM is dedicated to the mission of promoting exercise science, physical activity, and fitness in the health and medical care of children and adolescents. That mission is accomplished in part through scientific meetings, a scholarly journal (Pediatric Exercise Science), collaborative research, student aid in the form of grants and awards, and a training program database.