What’s in a running game? How do you fix one that’s broken? What is the autopsy like, figuring out what all the component parts look like, and how to make them better? The most obvious piece of the puzzle is the running back, the guy doing the running, but it is argued as to how relatively important he is to the total success of running the ball.
There is also the offensive line to consider, and their blocking. And their coaching. There is the play-calling. There is the perimeter and in-line blocking from the wide receivers and tight ends.