If a player can find a way to get to average 100 yards per game over the course of an entire season it’s very likely they will lead the league in rushing. In most seasons no more than two players (often one) will top 100 yards per game. Even averaging 70 yards per game will likely land a player in the top ten. Consistently hitting 100 yards per game on the ground is challenging for any running back, even the elite backs. It requires some luck and playing for a team that either wins most of its games (thus being able to rely on the run more often) or having an average or subpar quarterback who is unlikely to consistently move the offense by throwing the ball.