1) Late 19th century influential figures like Theodore Roosevelt, John L. Sullivan, and Walter Camp used sport to project their views and identities, influenced by Social Darwinism.
2) Roosevelt boxed in college and befriended champions to portray himself as physically fit and capable of survival. Sullivan revolutionized boxing by allowing public fights, self-promoting extensively.
3) Camp helped develop American football from rugby at Yale, introducing rules that made the sport more strategic and dangerous, fueling growth of intercollegiate competition influenced by ideas of survival of the fittest.