Dr. Crespo's previous work experience includes working for the State University of New York at Buffalo as an associate professor and as a researcher at Roswell Park Cancer Institute as well as the Centers for Disease Control and Prevention in the National Center for Health Statistics. His responsibilities included survey planning and development of the National Health and Nutrition Examination Survey. He also worked as a public health analyst for the Office of Prevention, Education and Control of the National Heart, Lung, and Blood Institute at the National Institutes of Health. He was an assistant professor at American University in Washington D.C.
His main area of research involves the epidemiology of physical activity in the prevention of chronic diseases and research on minority health issues. He has over 60 publications in the areas of exercise, minority health, obesity and nutrition, and is co-author of five textbooks on minority health and sports medicine. He is also a contributing author to more than ten government publications, including the "Surgeon General's Report on Physical Activity and Health," and the "Sixth Report on Detection, Evaluation and Treatment of Hypertension." He received the 1997 Secretary of Health Award for Distinguished Service as part of the Salud para su Corazon campaign, and in 2003 became a Minority Health Scholar at the National Institutes of Health. He is an emeritus board member of the American Council for Exercise, former member of the board of directors of CASA de Maryland, and past president of the mid-Atlantic regional chapter of the American College of Sports Medicine. Currently he serves as a senior technical adviser for the Montgomery County Latino Health Initiative, CDC external advisory committee for the First International Physical Activity and Public Health Conference, and is a WHO/PAHO consultant for the Latin American Obesity Prevention Initiative.