In my opinion, take our NFL athletes, allow them to play Rugby for a year to learn the nuances of the game with a competent coaching staff guiding them and it would be game over for the rest of the world. Those guys are are on a level separate from any other athlete I have personally seen, regardless of the sport.
American Football is where our best athletes are at.
btw, take your all-star Rugby players, put them on an American Football team without gear and they'd be in the hospital in the 1st quarter..... problem is, it would never happen, simply because they wouldn't make the team anyway. :-D ..... if you have no talent, they send your ass home here.
Good thing they all had their helmets & padding on or they would have got hurt...oh thats rite they don't !!!