GREEN BAY, Wis. -- Changes to the NFL's kickoff rules appear to account for a slight decline in the number of concussions reported across the league last season, according to a consulting firm's study of injury data provided by the NFL Players Association.
Jesse David, senior vice president at Edgeworth Economics, said the number of concussions reported on kickoffs decreased by about 43 percent from 2010 to 2011. That led to a slight drop in the overall number of reported concussions, reversing a multiyear trend toward more head injuries, he said.
"Most concussions are happening somewhere else, but kickoffs was one that they felt, I presume, that it was pretty easy to target," David said Tuesday, in an interview with The Associated Press. "And it looks like the rule did what it was supposed to do."
The NFL moved kickoffs up five yards to the 35-yard line last season, an attempt to increase the number of touchbacks and de-emphasize kick returns -- one of the most violent and chaotic plays in football.
The reduction in concussions on kickoffs was among the most significant findings in the study by Edgeworth, which has done consulting work for the NFLPA in recent years. Although the players' union no longer retains Edgeworth, it continues to provide data for the firm to study independently.
There were 266 overall concussions reported in 2011, a decrease from the 270 reported in 2010. The number of concussions that occurred on kickoffs dropped from 35 in 2010 to 20 last season.
"Obviously, touchbacks are very unlikely to have a concussion on the field," David said. "Not impossible, because there's blocking going on and that sort of thing, but the big hits are going to be reduced, obviously, by not having a return."
The number of reported concussions had been on the rise since 2006.
"As an economist and a statistician, I can't tell you whether that's due to increased recognition of concussions versus an increased incidence of them," David said. "It's probably both. But nonetheless, you see a pretty significant (trend) over the last five years, roughly. However, in 2011, we saw a decrease -- a slight decrease in the total number of concussions, the first time that's happened in several years. And that is entirely due to a reduced number of concussions during kickoffs."
David said the data used in their study comes from the NFL's internal injury surveillance system and classifies injuries as minor (a player missed eight days or fewer, including injuries that didn't knock a player out of a game), moderate (8-21 days missed) or major (more than 21 days missed).
The overall number of injuries increased significantly, from 3,191 in 2010 to 4,493 in 2011. But the biggest increase was seen in the number of minor injuries, and David believes the big jump could be attributed to more accurate reporting of injuries.
"To us, what that says is there's an increased in recorded injuries, but probably not an equivalent increase in actual injuries," David said. "Which means the ISS is simply getting better at tracking injuries, that reflects the increased focus that the league and the teams put on following what is actually happening on the field."
Still, David noted that the number of injuries classified as moderate or major is still on the rise.
David said there were 633 moderate injuries in 2010, and the number jumped to 739 in 2011.
"The game is still getting more dangerous," David said.
And David said there was a new aspect to the data available this year: the opponents when player injuries occurred.
The five teams that caused the fewest injuries were the Bills, Washington Redskins, Dallas Cowboys, New York Jets and New York Giants -- proof, perhaps, that a team doesn't have to inflict pain to win the Super Bowl.
"If you told me the Ravens and the Raiders caused the most injuries, I guess I wouldn't be surprised," David said. "But again, since we only have one year (of data), I don't know how much you want to take away from that."