A simple rule change in Ivy League football games has led to a significant drop in concussions, a study released this week found.
After the Ivy League changed its kickoff rules in 2016, adjusting the kickoff and touchback lines by just five yards, the rate of concussions per 1,000 kickoff plays fell to two from 11, according to the study, which was published Monday in the Journal of the American Medical Association.
Kickoffs, during which players sprint down the field and can knock into each other at full speed, had previously represented an outsize number of concussions.
The study comes amid a broader push to adjust kickoff rules at all levels of football and offers a strong indication that touchbacks can help reduce the risk of head injury in a sport grappling with the competing priorities of entertaining its audience and keeping its players safe.
“We see really compelling evidence that, indeed, introducing the experimental kickoff rule seems to be associated with a large reduction in concussions,” said Douglas Wiebe, the lead author of the study and the director of the Penn Injury Science Center at the University of Pennsylvania.
In 2015, kickoffs during Ivy League games accounted for 6 percent of all plays, but 21 percent of concussions, the study said. So Ivy League football coaches decided to change the rules to encourage kicks into the end zone.
Under the new system, teams kicked off from the 40-yard line, instead of the 35, and touchbacks started from the 20-yard line, rather than the 25.
The result? A spike in the number of touchbacks — and “a dramatic reduction in the rate of concussions,” Dr. Wiebe said.
The study looked at the rate of concussions over three seasons before the rule change (2013 to 2015) and two seasons after it (2016 to 2017). Researchers saw a larger reduction in concussions during kickoffs after the rule change than they did with other types of plays, like scrimmages and punts, which saw only a slight decline.
The Ivy League — an N.C.A.A. conference that includes Brown, Columbia, Cornell, Dartmouth, Harvard, Pennsylvania, Princeton and Yale — has been among the most aggressive college conferences in addressing the risks associated with the collisions that are endemic to the game. In 2016, Ivy League football coaches took the extraordinary step of eliminating all full-contact hits from practices during the regular season.
But the N.C.A.A. as a whole has also taken action to target kickoffs. For example, a new rule this season allows receiving teams to wave for a fair catch anywhere inside the 25-yard line and have it result in a touchback.
In a statement on Monday, the N.C.A.A. said that it had an early look at Ivy League concussion data before approving its new rule.
“Ivy League concussion data were initially presented to the N.C.A.A. and numerous other relevant stakeholders in early 2018,” the statement said. That data was among the information, it said, that “contributed significantly to the discussions and analysis that resulted in new football kickoff rules for the 2018 season.”
The N.F.L. has also made changes to kickoff rules and saw a reduction in concussions after it moved its kickoff line from the 30-yard line to the 35 before the 2011 season, according to the league’s own figures.
It also implemented a new rule this year that requires players to line up near the kickoff line, rather than allow them to make a running start.
Dr. Wiebe, the lead author on the Ivy League study, said, “It’s great to see a success story here.” But he noted that plays other than kickoffs also result in concussions.
“We do need to step back and think about the rest of the game,” he said.
