Defending a championship is hard in any pro sport. In a world full of alpha athletes, you become the hunted, the one that other great teams and players — all of whom are, by nature, far more competitive than you or I could even dream of — measure themselves against.
Nowhere, however, is this more evident than the National Football League, by far the most physical team sport in America. And 16 games of being the hunted, of getting the other guys’ best shot, is … well, draining. Especially in the modern era, where players have never been bigger, stronger and faster.