The emergence of leisure as a middle-class passion in the 19th century gave rise to organized sports at the same time evangelical Protestantism was enjoying its heyday. The two came together in the Muscular Christianity movement in England and America that gave birth to the YMCA network and other efforts to join sport and faith.

The alliance only grew closer in the 20th century. The famous evangelist Billy Sunday was a former baseball player who used sports as a tool for conversion, and other evangelists have followed the same tack. The Promise Keepers men's movement was founded in 1990 by a football coach in a football stadium and is in keeping with the American evangelical tradition of combining sports and faith to attract men to church.

Catholic colleges also rode sports success to acceptance in the American mainstream.

The comfort level among Christians with sports is such that few think twice about watching—or playing—sports on Sunday or other holy days—activities that would have once been considered taboo. Contrast that with the continuing debates about whether Jewish players (such as the Dodgers' Shawn Green in 2004) should play on holy days such as Yom Kippur or the struggles Muslim athletes have in fasting during Ramadan while continuing to compete.

While Christianity remains the principal arena for the mixing of sports and faith, American athletes are increasingly reflecting the introduction of other religious traditions. The ancient Hindu discipline of yoga has become a fitness craze for mind and body, while Eastern martial arts practices such as karate, kung fu and tai chi (which were started to get sedentary Buddhist monks into better shape) have become enormously popular as means to fitness and to athletic success.

Among the many evangelical groups focusing on God and sports is The Fellowship of Christian Athletes, which is based in Kansas City, Mo., and is the leading Christian organization for professional and student athletes. The ministry aims to evangelize through sports and has members sign a Competitor's Creed to be on Team Jesus Christ. The FCA was founded in 1954, and its huddles meet regularly on nearly 8,000 junior high, high school and college campuses for prayer, Bible study and other activities. Les Steckel, a former National Football League coach, is president and CEO. Steckel was head coach of the Minnesota Vikings and was the offensive coordinator for two teams that reached the Super Bowl: the New England Patriots in 1986 and the Tennessee Titans in 2000.