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 helmets 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 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 and 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 2013. The sensors measure head hits and relay the information to sideline personnel equipped with smart devices. Those devices report a metric measuring the velocity of the hit that could be used to determine if a player, for health and safety reasons, should come off the field.
Just last year, a committee member, Kevin Guskiewicz, a professor at the University of North Carolina, where the football team uses the sensors, said he expected the entire league to use them for the 2015 season.
Richard Ellenbogen, chairman of the committee, said the NFL is not turning its back on sensors and hopes a newer, more reliable system is soon ready.
The NFL has used a group of scientific advisers since 1994, when the mild traumatic brain injury committee was formed. It was renamed with its current moniker in 2010. 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.
John Ralston, CEO of X2, said the findings proved helmet sensors do little more than measure hits to a piece of equipment — not to the head. The helmet, for example, 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 spokeswoman 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.”
Stefan Duma, department head, biomedical engineering and mechanics at Virginia Tech, works with Riddell’s sensors, which are used by teams at the university. He disagreed with the NFL’s new position, citing dozens of studies that back the sensors and noting that Pop Warner used the data in 2012 in deciding to cut back on practice times.
“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.”
