Above and beyond the action on the field there are a lot of other aspects of a football game at every level that most fans never see or know about.  When the head coach meets with the officials before the game one of the things he's asked about is the identity of his "get back coach". 

If you'd ask the average fan they'd have no idea what you're talking about if you mention a "get back coach", but simply he's someone on the staff who's responsible for making sure that players, coaches and others associated with the team stay within the boundaries of the team box.  It ensures that the game officials have a clear path along the sidelines as they focus their attention on the action on the field.

If the path of a game official is impeded by someone along the sidelines it's an automatic foul, so that's why the job of the "get back coach" is so important.  The coach of the Los Angeles Rams has his own personal "get back coach" and you might catch a glimpse of him from time to time during Sunday's Super Bowl.  Check out this hilarious Youtube video of what a typical game for him is like.