The Igon Value of Football

24 November 2009 at 3:34 pm Dick Langlois Leave a comment

| Dick Langlois |

My last post implicitly lauds the science reporting of the New York Times. And I think they generally do a good job. But, still basking in the glow of UConn’s remarkable football win over Notre Dame on Saturday, I am reminded of a — presumably unintentionally — funny bit of science reporting recently in the Times. Reporter Alan Schwartz has been waging a (perhaps justified) campaign about the problem of head-injury risk in football. In one article last month, he quotes a neurosurgeon on the physics of football collisions.

“I go back to Einstein and E = mc²,” said Julian Bailes, a former Pittsburgh Steelers neurosurgeon and one of the leading researchers in the neurological effects of football concussions. “The players are definitely much more massive and that’s one factor. But you have 300-pound linemen running 4.3s — and that factor is squared. The impacts that players face today, not just the big ones that everyone sees but the routine ones in the trenches, is what really worries me.”

Converting the mass of a 100Kg football player (light by NFL standards) into energy according to the Einstein formula would yield about 2,000 megatons of energy, probably enough to cause head trauma even in an NFL lineman. (It is the quoted source who makes the mistake, but the reporter and his editors didn’t catch it or at least didn’t remark on it or change it.)

When I was in high school, the assistant football coach was also the physics teacher. He tried to psych us up for one game against (as always) a bigger and more talented opponent by quoting the correct version of the mechanics of collision — energy goes up as the square of your velocity, not the square of the speed of light. How fast you get going, he was telling us, is much more important than the weight of the opponent. I found this a refreshing change from the usual cliché about the manner in which the opposing players were likely to don their athletic supporters. But under the circumstances, and especially as I was one of the few who had any idea what he was talking about, I declined to point out that smacking into another football player is an inelastic collision, so energy isn’t conserved. Momentum is always conserved, but that’s linear in both mass and velocity. I didn’t play football very seriously or for very long, but I am happy to blame the experience for my increasing mental lapses as I grow older.

Extra point. By the way, the inelastic collision pictured above is between Notre Dame running back Armando Allen and UConn middle linebacker Greg Lloyd (son of the former Pittsburgh Steeler of the same name) at the goal line on Saturday. UConn won the game in the second overtime. In college football, each overtime session allows both teams a single possession from the 25-yard line. In the first overtime, both teams scored a touchdown and an extra point. In the second overtime, UConn held ND to a field goal and then scored a touchdown on their turn, thus winning the game. This differs from the professional rule: sudden death. On Sunday, the Patriots beat the Jets in overtime because they won the coin toss and then quickly got close enough to score a field goal. Thus, in the pro game, the coin flip determines the outcome with high probability, a circumstances that rightly causes consternation among fans. Economists have suggested auctioning off possession in overtime, with the currency being the field position from which you are willing to start. At the very least, they ought to use something like the college system.