How best to reduce concussions and other brain injuries that occur in American football continues to perplex scientists, coaches, and fans at all levels of the sport, but a new study published in JAMA points to one way to make the sport safer: move the kickoff line.

A 2016 and 2017 Ivy League experimental rule that moved the kickoff line from the 35- to the 40-yard line and the touchback line from the 25- to the 20-yard line reduced the average annual concussion rate by more than 68%, according to the research conducted by a team from The Ivy League and Perelman School of Medicine at the University of Pennsylvania.

Kickoffs occur multiple times throughout the course of a football game, including at the start of each half and after a scoring play. During a kickoff return, a player from the receiving team who catches the ball has the option to return the ball while the opposing team attempts to tackle them, or to take a knee.

This specific play has a much higher rate of concussion than other plays in the sport, most likely due to the high speed at which collisions can occur. In 2015, kickoffs in Ivy League football, a NCAA Division I conference of eight private universities, accounted for 6% of all plays but 21% of concussions.

Changing the kickoff line

Seeing the risk of injury in these plays, in 2016 Ivy League football coaches recommended changing the kickoff line in hopes of causing more kickoffs to land in the end zone, thereby causing touchbacks—where the receiving player chooses to not advance the ball.

"The national conversation on concussions that occur in football can be informed by scientific research aimed at making sports safer," said senior author Douglas J. Wiebe. "We've found that this simple yet strategic policy change helps sustain the quality of the game, while also making it safer for student athletes."

Using the data from this concussion surveillance system database, the researchers identified the concussions that occurred in regular season in-conference games before the rule (2013-2015) and after the 2016 rule (2016-2017) by the type of play: kickoff, play from scrimmage, punt, and field-goal or point-after-touchdown attempts.

In 68,479 plays during 2013-2017, 159 concussions occurred, an overall rate of 2.3 for every 1,000 plays. Kickoffs resulting in touchbacks more than doubled from an average of 17.9% per year before the rule change to 48% after.

Concussion rates 

The rule caused average annual concussion rates (per 1,000 kickoffs) to go from 10.93 before the rule change to 2.04—a decrease of 68.8 percent. Concussions in non-kickoff plays also went down after the rule change, from 2.56 (per 1,000 plays) to 1.18 (per 1,000 plays).

"This swift action by Ivy League leadership, supported by rigorous injury epidemiology, is a compelling example of how collaboration and targeted policy change can be effective in reducing sport-related concussion in football and in other sports," said Bernadette A. D'Alonzo. 

"The Ivy League Presidents identified concussion injuries as a significant student-athlete welfare issue and charged the Ivy League sports medicine staff with taking a leadership role in identifying interventions that would make all sports safer," said Robin Harris. "We are proud to make this contribution to improving the game of football for our student-athletes."