With the bowl season of college football upon us, ESPN.com has been doing these polls where they ask readers who would win a hypothetical game between various pairs of "all-time great" college teams. A couple days ago, they asked about a game between the 2005 USC Trojans and the legendary 1955 Oklahoma Sooners. I looked up the rosters. The average weight of an offensive lineman on the 1955 Sooners team was 201.6 pounds. For the 2005 Trojans, the average weight is 299.7 pounds. I tried to project from contemporaneous track-and-field times what the likely difference in the speed of skill position players, but instead all one can say that is that the Trojans players are "way faster." So, in this hypothetical game, the Sooners would be at a ridiculous disadvantage of size and speed. I am sure, however, they are more crafty or plucky or something.
Actually, I just looked up the roster for the 2005 Odessa Permian high school team (the school that was the subject of the book and movie Friday Night Lights). The average weight of an offensive lineman there is 229.3 pounds.