American footballers are very big and i should imagine stronger than the average rugby player. You get absolute monsters in rugby aswell!! Just have to look at a french player called Sebastian Chabal!... But it just seems to me that rugby players are so much fitter than the footballers! An hour long American football game is churned out and lasts for 3hours. And you have two sets of teams (offence and defense i believe). Rugby players are hammer & tong at each other for 80minutes flat out! And as I'm writing this I also have 2 cracked ribs from a tackle from a player the size of my local supermarket!
And the money involved in American football is ridiculous. No sportsperson is worth that amount of money IMO!