The NFL is suspending efforts to track potentially concussive hits using helmet and head sensors, ending for now a program the league expected might expand to all teams this coming season. The decision followed league-funded studies of Riddell helmet and X2 Biosystems mouth guard sensors. The NFL concluded that the compiled data was unreliable, underscoring the challenges the sport confronts trying to quantify when a hit should lead to a player being pulled from a game. The studies have not been published.
“The bottom line is the recordings of these sensors right now, the accuracy is suspect,” said Dr. Robert Cantu, an adviser to the NFL’s Head, Neck & Spine Committee, which managed the studies and the related sensor pilot program. “I think it is prudent to put it on the shelf.” The league began the pilot program with several teams in ‘13 and continued on a modest scale in ‘14. The sensors measure head hits and relay the information to sideline personnel equipped with smart devices. Those devices then report a metric measuring the velocity of the hit that is used to determine if a player, for health and safety reasons, should come off the field.
Just last year, a committee member, Univ. of North Carolina professor Kevin Guskiewicz, where the football team uses the sensors, said he expected the entire league to use them for the ‘15 season. Committee Chair Richard Ellenbogen said the NFL is not turning its back on sensors and hopes a newer, more reliable system is soon ready. “Is it going to give us accurate information, so we can modify play on the field or evaluate players,” Ellenbogen said. “The answer is, right now we are not at the stage with the data that it is reliable so we can do that.”
The NFL has used a group of scientific advisers since ‘94, when the Mild Traumatic Brain Injury Committee was formed. It was renamed with its current moniker in ‘10, after coming under sharp political and scientific attack for publishing research that downplayed the link between concussions and playing football. The committee advises the league on best practices for concussion prevention and management, studies injury data and equipment research and distributes up-to-date protocols to teams for handling head, neck and spine injuries. Under the mandate, the committee has been studying the field of sensors that measure the impact of hits to the head.
Three years ago, laboratories were producing solid results from the helmet sensors, known as accelerometers, Cantu said. The problem, he said, is that those results measured direct, center-of-gravity hits on the helmets, instead of tangential ones more common on a football field. The NFL, on the advice of the Head, Neck and Spine Committee, paid for studies at Biokinetics in Ottawa and the Southern Impact Research Center in Tennessee for testing of Riddell’s Sideline Response sensor system and X2’s mouthguard and head sensors, Cantu said. Each laboratory studied all of these sensors. “Those studies have shown the accuracy deteriorated” with hits that were not center of gravity, Cantu said.
X2 CEO John Ralston said the findings proved helmet sensors do little more than measure hits to a piece of equipment -- not to the head. “The NFL has almost certainly recognized and has very little interest going forward investing assets in player helmet sensors,” he said. “A helmet with a sensor is not that much help.” Ralston’s point is that the helmet might not detect whiplash or other sudden head movements that may not even be caused by a hit. As to the NFL’s finding of his mouth guard sensors, Ralston said, “Plenty of studies show how accurate our product is.”
Riddell through a spokesperson offered the following statement: “Riddell’s Sideline Response System (SRS) continues to be a valuable tool in understanding the exposure of athletes to head impacts during play. Its track record providing information has led to significant rules and equipment changes to better protect athletes. Beyond that, we cannot speak for the NFL or their many considerations.” Virginia Tech professor Stefan Duma also works with Riddell’s sensors, which are used by teams at the school. He vehemently disagreed with the NFL’s new position. “It comes down to what accuracy do you need to be useful,” he said. “In my opinion, 10 to 20 percent variation is acceptable.”
Duma cited dozens of studies that back the sensors and said Pop Warner used the data in ‘12 in deciding to cut back on practice times. He questioned why the NFL would reject sensors that aided youth leagues. “The concern I have is making a public statement like this has larger impact,” Duma said. “The notion that the technology is not advanced enough and doesn’t get good data is a difficult position to defend right now because a lot of the data did a lot of good.”
Duma has another theory why the NFL turned its back: the league and players union do not want the data collected. “I don’t think anyone wants a record of it,” he said. The NFLPA has expressed concerns in the past how the data could be used against players in contract negotiations, Cantu said. A team, for example, might look less favorably on a player if there were a metric showing he has taken more hits than another player who is competing for the same contract. That issue, Cantu said, held up the pilot program last year before the data issue ended it. The NFLPA did not respond for comment.
