Umm. By far the biggest reason for the shift is the specialization factor, mainly spurred by NOT playing both sides of the ball (offense and defense). Which to be fair, the video did point out.

The video didn't come right out and directly say that was a bad thing, but heavily implied it. I disagree, and think that it is one of the coolest things about American Football. Different positions require (or at least reward) different skillsets and physical attributes. So at the highest level of play, yes, O linemen are going to be huge and stable on their feet. D linemen are going to be slightly less huge, but faster and more aggressive. D backs and receivers are going to be tall and fast. Running backs can excel by being smallish, elusive, and quick, OR large and resilient. And so on.

That specialization makes the game fascinating -- seeing how teams with different balances of specialists can compete with each other and be more or less effective in different situations or against different teams.

Are NFL linemen going to be more at-risk for conditions like heart disease? Of course -- any sample group made up of people that weigh as much as NFL linemen is going to have greater occurrence of heart disease. But that isn't something unique to football players / the NFL. In fact, if you compared rates of heart disease in current / former NFL linemen to a sample group with the same average weight who were NOT football players, they'd probably have a lower rate, because like the video said, those linemen generally still had to be in very good physical shape -- just heavy.

I guess what I'm saying is that it seems weird to insinuate that it is a bad thing for the NFL / football in general to "encourage" health issues directly or indirectly because they select for large / huge players. If you want to point out unique risks of playing in the NFL, there are way more pressing and direct issues -- like RBs having LOTS of mobility problems after they retire due to all the bone / joint damage from getting tackled all the time, or increased risk of chemical dependency in football players in general due to all of the pain and other meds that teams pump into players to keep them going.

Moving this video to ant's personal queue. It failed to receive enough votes to get sifted up to the front page within 2 days.