Originally Posted by Hoofbite
There is genetic variance for just about every conceivable human trait. For NFL athletes, that means pain tolerance, rate at which injuries scar, ligamentous laxity/tautness, bone density, natural muscle tone, on and on.
I've got a buddy who works with high performance athletes including some NFL players, doing rehab and repair work. He makes the point that many of them just don't have a pain threshold that is anything like the rest of us. It's not that they're tougher than the rest of us, their system just doesn't register things as painful the way us mortals do. They have to have that to be able to withstand the abuse they take.