look, this game has changed. you were referring to past history, but they say, players have become bigger, they've become faster, stronger, and is it possible to make football a safe game? >> well, that's a fabulous and difficult question, as you know. the problem is, it's the size and speed and power of the professional athletes at this time, which is enormous. it's also a fizz lonphysiologic problem. we've got great armor and these helmets are great, but when the helmets collide at great rates of speed and stop, the skull stops almost immediately, but unfortunately the brain doesn't. and that moving back and forth, that reverberation is the villain here. >> you mentioned all these various, you know, propositions, including, you know, the sideline exam. as advisers to the nfl, how do you enforce that? because there is this culture of