Purdue coach Joe Tiller is leary about moving kickoffs back five yards, and he's bringing the science:
"It's probably going to add a few more injuries that we didn't have in the past. And maybe a few more kicks will be returned."
I'm eagerly awaiting the preprint from Tiller et al. on kickoff yardage and the curvature of spacetime to hit the arXiv server. It should revolutionize science as we know it.
But putting aside the misuse of science terms, I don't think Joe has much to worry about. Assume kickoffs do result in more injuries, because of the increased momentum - that's mass times velocity for those of you that spent your college years in underwater basketweaving - the players are colliding at. What will moving the kickoff back five yards accomplish?
Well, the kicking team will have to run farther. But they're already running 45-50 yards as is. I somehow doubt they're being prevented from hitting top speed by a lack of five more yards to accelerate. Most of these guys collide with blockers, who aren't worried about building up speed, they're trying to stop the very large man barrelling at them. I doubt thse collosions will have any more momentum than they did last year.
Which leaves the guy with the football, who will take advantage of that extra space and hopefuly will be running faster than he does now. Of course, he also won't be trying to collide with members of the kicking team. So I don't really think his downfield momentum component is going to be increased by very much.
I'd be really surprised if there's an increase in special tams injuries above that resulting from more kicks being returned out of the endzone. And since increasing returns ws the reasoning behind the rule change in the first place, I think the chance of injury is low enough to not worry about. Rest easy, Boilermaker physicist-football coaches, your charges are safe from the NCAA.