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Helmet technology making an impact

Several major football programs use the Head Impact Telemetry System to measure the force of every hit on the field.


By Brian Burnsed

In practice, lost amid a storm of bodies, a player is caught by a vicious blindside block.

It’s a clean hit, but far from the ball, and the coaches’ and athletic trainers’ eyes are affixed elsewhere. They don’t see the player’s head whip back violently as his feet are taken from under him. They don’t see is helmet slam into the turf. But there was no sound of shoulder pads clicking together, no distinct pop of helmets colliding to draw their attention.  
It’s a silent concussion.  

The player is dazed, but is able to get to his feet without staggering. He stays in to play another snap, to endure more drills and more hits with his head lost in the fog. It’s an unfortunate scene that, despite the vigilance of trainers and coaches, is bound to happen on football fields nationwide every fall. But at a few schools, those subtle hits, the ones away from the play that evade even the most careful eye, are always noticed.  

How? Several football programs have fitted players’ helmets with accelerometers that measure and instantaneously relay head impact data. They can discern the force of the hit, the linear acceleration, the rotational acceleration and can pinpoint exactly where the impact occurred on the helmet. Athletic trainers and team doctors are alerted by their computer screens or pagers and can immediately pull a player from practice or a game. Or they can simply monitor him closely through the next few plays to detect if he’s behaving abnormally and talk to him or perform a concussion test when he returns to the sideline.  

The technology, developed by athletic-tech company Simbex and used in Riddell helmets is dubbed the Head Impact Telemetry System (better known as the HIT System). Schools such as Virginia Tech, North Carolina, Oklahoma and Dartmouth are using the system to monitor head impacts in real time and to help players change on-field behavior and technique in order to prevent future concussions.

“The HIT System is giving us the data that we might not always see,” Virginia Tech associate director of athletics for sports medicine Mike Goforth said. “The concussion that occurs, or the big blow that occurs – and we don’t see it with our own two eyes – we at least have the device to notify us that there has been a blow.”

Virginia Tech, the first school to put the accelerometers in players’ helmets, started using the system in 2001. Stefan Duma, head of the Virginia Tech-Wake Forest School of Biomedical Engineering and Sciences, learned of the technology and approached the football team training staff, touting its potential practical and research benefits. Goforth was intrigued and pitched the idea to head coach Frank Beamer, who was happy to oblige the researcher. Quickly, more than 60 players, all who played regularly and were in positions with the highest concussion risk, agreed to take part and began wearing helmets fitted with the unobtrusive accelerometers that tuck into crevices between a helmet’s padding.

Now, Virginia Tech assistant athletic trainer Brett Griesemer carries a pager during practices and games. When the HIT system measures a collision that exceeds 98 Gs (or 98 times the force of gravity) his pager immediately alerts him which player has suffered the blow. Griesemer will then notify Goforth and team doctors, who will either pull the player off the field and commence concussion testing or watch him closely, looking for signs of a concussion.

A 98 G hit doesn’t mean that a player has suffered a concussion – in fact, researchers can’t definitively say if concussions can be triggered by one or two severe hits or a gradual buildup of many smaller ones – but research suggests that a hit of that magnitude could put someone at a higher risk. Trainers at most schools with the technology do not use the system to diagnose a concussion on the spot. Rather, it can trigger them to implement their concussion protocols, including basic observation, question-and-answer testing or ImPACT computerized cognitive testing.

“It’s just another piece of the puzzle for us,” Goforth said. “You can’t put all your eggs in the ImPACT basket. You can’t put all of your eggs in the sideline assessment basket. You’ve got to look at the whole clinical picture, and [the HIT System] is just one little part of it.”

In 1999, Kevin Guskiewicz, now chair of North Carolina’s department of exercise and sport science, secured an NCAA grant that allowed he and other researchers to perform a concussion study on student-athletes at 29 Division I, II and III schools. Their efforts led to the NCAA Concussion Study, which, when published, was the most comprehensive study of the injury in athletics every done. The Centers for Disease Control took note of Guskiewicz’s work and provided UNC with another grant. The school used the funds to procure the HIT System in 2004, which costs about $1,000 per helmet. Since then, Guskiewicz and his colleagues have published a pair of papers on their findings and have another in the works. Over seven seasons, more than 350,000 head impacts have been recorded in practices and games. Among myriad other discoveries, they’ve found that after one concussion, a person has a two-to-three times greater chance of suffering another and that if a player suffered at least three in a five year window, his chances of suffering another quadruple.
“The NCAA [grant and] study from just four or five years earlier really sort of set the stage for this groundbreaking work that has really allowed us to better understand the biomechanics of concussion,” Guskiewicz said.

Beyond the forward-looking research, the HIT System has already demonstrated tangible benefits for today’s players. Both UNC and Virginia Tech use the HIT data, which can be broken down player-by-player and practice-by-practice, to implement behavior changes. If a player suffers repeated head or neck injuries or researchers notice a preponderance of high-magnitude hits at the crown of the head, they will sit down with that player and review the data and practice and game film in concert to demonstrate where poor technique led to dangerous, high-impact collisions. Those typically occur when a player lowers his head while tackling, making a block or bracing for an impact.

“It’s numbers that we can give to the athlete to say, “You see when you hit this way, you had a really bad hit. When you hit more properly or with a better technique, the impact on your head wasn’t as large,’” said Jason Mihalik, assistant professor in the department of exercise and sport science at North Carolina. “We’re using that to change the way that athletes tackle, the way they play, not to make them any less effective a player, but to make it a safer game for them.”

And it’s working. When UNC began their studies, Mihalik said that as many as 20 percent of impacts were occurring at the top of the head, which implies poor form and puts the player at a greater risk of sustaining a concussion. Though, in recent years, that number has fallen to about 13 percent, suggesting that players are learning from the HIT system data and coaches are using it to improve their instruction of proper technique. North Carolina coaches even use the system as a recurring tool, touting that the technology and the data will ensure that student-athletes play safer.

But the HIT System is far from the be-all and end-all for concussion research and prevention – Guskiewicz feels it’s merely the tip of the iceberg. He notes that the technology and our understanding of concussions aren’t advanced enough to simply rely on impact force, acceleration and location to diagnose a head injury. The HIT System could serve as a useful bridge for football programs until researchers get a better handle on an injury with seemingly amorphous causes, symptoms and consequences. Now, many researchers and scientists are pinning their hopes on finding biomarkers that could be detected in blood or urine samples, which would indicate that a concussion has been sustained.    

“We can’t see a concussion,” Guskiewicz said. “It’s been described as a functional injury, not a structural injury that can be easily seen on imaging. We’re beginning to work with some companies that are going to hopefully helps us better understand how to identify a biomarker that will allow us to take the guesswork out of this.”

In the meantime, researchers and trainers who have used the HIT System are adamant that other schools adopt it. Goforth, at Virginia Tech, said that it’s helped him identify at least two players who were concussed that he would’ve otherwise missed. Though that’s a low number, he said the fact that the system enabled him to get those two players out of harm’s way immediately justifies paying for the pricy technology. Plus, there’s no way of knowing how many concussions have been prevented thanks to those many behavior modification sessions.  

“There’s no doubt everyone should have this,” Goforth said. “I don’t think we can ever, with our naked eyes, detect every concussion.”