Soccer referees are certainly the fittest officials in all of sports. To be able to make calls, a referee has to remain close to the ball while it’s in play, which means 90 minutes of almost non-stop running. Soccer players run an average of seven miles per game, and the referee has to match that performance. According to Runner’s World, referees run anywhere from six to eight miles a game, which dwarfs that of NFL, NBA or MLB players.

MLS referee Mark Geiger, who will represent the United States at the World Cup, also noted that the most important decisions in a game come when the referee is tired, so building up stamina before a major game is priority number 1. To be eligible to work at the World Cup, Geiger had to pass a strenuous FIFA fitness test in which referees must do a number of sprints in succession, then complete a longer run with a at least a 5:20-mile pace.

Via Runner’s World: