112 of Jones' 185 carries last season came in the final eight games.
"I don't think he had the confidence to run the ball as a coordinator (early in the season) because he didn't feel they had earned the ability to do it during the course of the week," Johnston said. "They weren't physical enough. They didn't have their pad level down. It was too big of a change on a Sunday."
His promotion placing him in charge of the team's practice routine, Garrett's changes yielded better results and developed a more physical presence in the running game.
"Now I can come back to that," Johnston said, "because I have the confidence that I can do this effectively. Nobody wants to be second-and-10 or second-and-12.
"That came from Jimmy's environment, Nick Saban's environment (in Miami, before Garrett joined the Cowboys' staff)."
As head coach, Garrett has since stressed the importance of a physical training camp (if there's one) -- not daily pads practices, but certainly more often. He thinks it lays the foundation for a taxing season, as well as a productive running game.
And no matter who's in the backfield this season -- Felix Jones, DeMarco Murray, Tashard Choice, Marion Barber -- they'll have to build on those final eight games.
They've already shown they can run. They just have to run all season.