Radiolab has a recent episode about the early years of football, with particular reference to the Carlisle Indian School and Pop Warner. Pretty interesting--especially considering that the speed/spread vs power running dynamic they describe is still with us.
https://itunes.apple.com/us/podcast/radiolab-from-wnyc/id152249110?mt=2&i=334478260
https://itunes.apple.com/us/podcast/radiolab-from-wnyc/id152249110?mt=2&i=334478260