This is a very well known phrase in England, but it refers to football (soccer) and rugby. I have never heard this in reference to American football and cannot even imagine how the meaning would translate.
The meaning of it comes from football being a supposedly gentle game of skill, but played and loved by the common people and with a long history of bad behaviour on and off the pitch, versus rugby being a rough, bruising, injury riddled sport that was played by aristocratic rich kids in private schools who are all excellent young men destined for greatness.
Of course this is mostly oversimplified bollocks, but with just enough truth behind it to make it funny.
My daughter is 10 now, but your comment triggered a memory I had buried so deep it was all but forgotten.
The rule was that we put the child on its back, undo her diaper and fold the front down, blow on her exposed nethers and then close the diaper again and wait. She immediately pees, every fucking time, I change her, she stays dry for longer, I get some fucking sleep.
I just reminded my wife of this ritual. We laughed. Take this forgotten knowledge from survivors of the bad times, whoever might read this.