It is just pure physics. The energy created from bigger guys (mass) moving faster (exceleration) equals energy, which is what is causing these concussions. You now have 325lb offense tackles down blocking on 260lb middle lbs, and all of these guys are moving... There was some research posted stating that once the average weight of NFL players crossed 220lbs (not counting specialists) there was a significant increase in head/brain injuries. (during the mid 70s if I recall correctly) 'Cause the truth is no helmet in the world can stabilize your brain, which is floating around in your skull. So at some point I think on both the college and pro level they will have to establish weight limits. The Service Academies have weight class football and have been doing so for years. As someone mentioned on here, you might even seen the return of the two-way player. Might do the sport some good. Never know.