"You spread people out, try to get the defense out of position, look for a mismatch and then try to hit a crease," said St. Louis Rams coach Jeff Fisher, who coached Chris Johnson in Tennessee when Johnson ran for 2,006 yards in 2009.

"We don't line up and run out of I-formation that much anymore" Fisher said. "The days when you lined up with the running back deep in the backfield and let him watch the blocking develop, that's done. Maybe once in a while or after you've been lucky enough to build up a lead and you're grinding it out in the second half. But that's situational stuff, not your base offense."