Walter H. Ettinger, MD, is a physician and university professor with a specialty in gerontology. He is also president of the University of Massachusetts Memorial Medical Center. A board-certified specialist in aging and the muscle and bone systems, Ettinger is a nationally recognized researcher, teacher, and clinician in these areas. He also published the seminal article demonstrating the importance and safety of exercise in people with arthritis.

Brenda S. Wright, PhD, is the vice president for program development for INTERVENT USA and a health promotion consultant. For 12 years she served as director of behavioral science and health promotion at The Cooper Institute in Dallas. There, she developed comprehensive lifestyle management programs for delivery at worksites, health and fitness centers, clinics and hospitals, and government agencies. She has also developed patient education materials for the Baylor Senior Health Centers in Dallas as well as health promotion programs for assisted living centers in Washington, Florida, and Texas. In 2002, Wright received the Distinguished Alumni Award in human ecology from the University of Texas at Austin.

Steven N. Blair, PED, Steven N. Blair was the senior scientific editor of the Surgeon General's Report on Physical Activity and Health in 1996 and received the Surgeon General's Medallion for his work. Blair is a Professor of Exercise, Epidemiology, and Biostatistics in the Arnold School of Public Health, University of South Carolina; and Executive Lecturer in the Department of Kinesiology, Health Promotion, and Recreation at the University of North Texas. He has served as the president of the American College of Sports Medicine (ACSM) and the National Coalition for Promoting Physical Activity. Blair has three honorary doctorates, a 1994 doctor honoris causa from the Free University of Brussels; a 1996 doctor of health science, from Lander University; and a 2002 doctor of science honoris causa, from the University of Bristol, UK. He also is a Benjamin Meaker Fellow at the University of Bristol.

All three authors are over 50 years of age.