It’s one of the most maddening plays in the NFL right now, the tush push. But you might not know the surprising backstory of the Philadelphia Eagles' signature move, and thanks to jason.kelce you don't have to wonder. The play was developed by Richie Gray, a former rugby coach from a small town in Scotland. This week on Sports in America, Richie tells us how he made his way to the NFL, what he thinks about all the tush push controversy, and why it's so unstoppable. #NFL #TushPush #Eagles