Reference books are a great place to start for background information. Here are some recommendations, divided into the following subject areas:
Scribner Encyclopedia of American Lives: sports figures by 
Who's Who of Sports Champions: their stories and records by 
African American Icons of Sport: triumph, courage, and excellence by 
African-American Sports Greats: a biographical dictionary by 
Outstanding Women Athletes: who they are and how they influenced sports in America by 
Women in Sports: the complete book on the world's greatest female athletes by 
Encyclopedia of Recreation and Leisure in America by 
Encyclopedia of World Sport: from ancient times to the present by 
Sport in American Culture: from Ali to X-games by 
Enhancing recovery: preventing underperformance in athletes by 
Historical Dictionary of the Modern Olympic Movement by Try these databases to find background information (important facts, dates, names, people, concepts, etc.) on your topic.
