American Football is like just about every other sport, in that it has a history of coaches with a little understanding of the sport's demands on its players. Football is a constant stop-start style to play, with the average play lasting no longer than ten seconds, followed by a much longer rest period. It's demands are closer to traditional sprinting and weight training methods. Compared to sports like Rugby or Boxing, where there is a far greater endurance element required. With that said, the sport has a big element of lateral mobility and technical considerations as well.