Rod K. Dishman, PhD, is a professor of exercise science, adjunct professor of psychology, and the director of the Exercise Psychology Laboratory at the University of Georgia at Athens. He is also adjunct professor in the Arnold School of Public Health at the University of South Carolina at Columbia. Dr. Dishman is a reviewer for more than 50 journals, including Journal of the American Medical Association (JAMA) and American Journal of Public Health. He has served on editorial boards of numerous journals in preventive medicine and public health, such as Exercise and Sport Science Reviews, Medicine & Science in Sports & Exercise, and Health Psychology and as an exercise consultant to public health agencies in the United States, Canada, and Europe. He has published approximately 150 peer-reviewed articles and written or edited several books related to physical activity and health. Dr. Dishman is an American College of Sports Medicine fellow, where he has served as a member of the Research Advisory Committee and the Board of Trustees. He was a member of the jury for selection of the Olympic Prize in Sport Sciences awarded by the International Olympic Committee's Medical Commission and served on the scientific advisory committee for the 2008 Physical Activity Guidelines for Americans. He resides in Athens, Georgia. Gregory Heath, DHSc, MPH, has been contributing to the field of exercise science and health promotion for over 25 years. Dr. Heath is Guerry professor and head of the department of health and human performance at the University of Tennessee at Chattanooga. Previously, he worked at the Centers for Disease Control and Prevention as lead health scientist in the Physical Activity and Health Branch. He has extensive experience in conducting studies and data analyses in the areas of physical activity epidemiology and public health practice. Dr. Heath is a fellow in the Council on Epidemiology and Prevention, the American Heart Association, and the American College of Sports Medicine. He earned his doctor of health science degree in applied physiology and nutrition and his master's of public health in epidemiology from Loma Linda University. I-Min Lee, MBBS, MPH, ScD, is an associate professor of medicine at Harvard Medical School, an associate professor of epidemiology at Harvard School of Public Health, and associate epidemiologist at Brigham and Women's Hospital in Boston. Her main research interest is in the role of physical activity in promoting health and preventing chronic disease. This extends to characteristics associated with a physically active way of life, such as maintenance of ideal body weight. She also is concerned with issues relating to women's health. Lee has published more than 190 peer-reviewed articles and is a frequent invited presenter, teacher, and speaker at local, national, and international levels. A reviewer for 30 journals, including Lancet and New England Journal of Medicine, Lee also serves on the editorial board for Harvard Women's Health Watch, Medicine & Science in Sports & Exercise, and the Brazilian Journal of Physical Activity and Health. Lee is an elected member of the American Epidemiological Society and a member of the Society for Epidemiologic Research, the American Heart Association, and the International Society for Physical Activity and Health. She is a member and fellow of the American College of Sports Medicine (ACSM) and has served on the ACSM's Research Advisory Committee and Board of Trustees. Dr. Lee also served on the scientific advisory committee for the 2008 Physical Activity Guidelines for Americans. Lee is the recipient of numerous awards and recognitions, in particular the Young Epidemiologist Award from the Royal Society of Medicine in the United Kingdom (1999); the William G. Anderson Award from the American Alliance for Health, Physical Education, Recreation and Dance (2007); the Charles C. Shepard Award from the Centers for Disease Control and Prevention (2009); and the ACSM's Citation Award (2011). Lee resides in Brookline, Massachusetts.