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A Helmet That Detects Hard Hits

Riddell is equipping football helmets with technology to identify when a blow could cause a serious injury.
September 10, 2007

There is a growing awareness that football players, from the high-school to the professional level, can suffer permanent brain damage from repeated concussions, even relatively minor ones. The impact of these blows often causes trauma to the brain that goes undetected by athletes, coaches, and medical personnel: athletes tend not to report potential injuries, while football staff often miss the signs of a concussion. Playing through such injuries puts an athlete in danger of sustaining further, more severe brain damage.

Crash helmet: Riddell’s new football helmet will be equipped with six accelerometers placed in its liner. The red circles in the top image show exactly where they will be placed. The sensors will measure the acceleration of the head and transmit the data to a computer to be analyzed. The results will let a player know the magnitude and duration of a hit, and its location on his head.

Now Riddell, a sporting-equipment manufacturer based in Rosemount, IL, is equipping its new line of helmets with sensors that measure the magnitude, location, and direction of a hit. The collected data can then be uploaded to a user’s computer and analyzed with a Web-based application. The helmet system will be sold to individual consumers for the first time this fall.

“The whole point of this technology is to measure the severity and location of head impacts, especially those that would otherwise go unnoticed, so that we can better understand when a concussion has occurred,” says Rick Greenwald, CEO of Simbex, a research and product-development company based in Lebanon, NH. The company specializes in biomechanical feedback systems and originally developed the technology, which was acquired by Riddell in 2004.

Riddell already sells similar sensor-equipped helmets to football teams like Virginia Tech, the University of Minnesota, the University of Oklahoma, and the University of North Carolina. The helmets sold to teams, like the helmets that will be sold to individuals, are equipped with sensors that receive impact data, but for teams, this data is continuously and wirelessly transmitted to a sideline laptop, where medical staff can monitor it. The team product includes a sideline response system so that if a player takes a hit above a certain predetermined threshold, an alert will be sent to a pager worn by a trainer.


  • See images of the hit system.

To shed light on the biomechanical causes of concussions, the National Institutes of Health (NIH) is currently funding a five-year study using data from the football teams at Virginia Tech, Brown University, and Dartmouth College. But the team system is “pretty expensive–$60,000 to $70,000. And with the individual helmet, you can receive the same type of data for about $1,000,” says Thad Ide, Riddell’s vice president of research and development.

The new helmet, called Revolution IQ Hits, will be arrayed with six accelerometers built into its liner that measure the acceleration of the player’s head, not the helmet. The accelerometers were made by Analog Devices and are the same type of sensors used in automotive airbags. The sensors measure both the linear and rotational acceleration of the head, and the resulting reaction force is expressed in g-force.

The data is wirelessly transmitted to a computer, which requires a plug-in antenna and the user to be within 20 yards of the helmet. The computer will be synchronized to a central server that interprets the data, calculating the magnitude of the hit and the location on the head using an algorithm developed by Simbex. The results are visually and numerically displayed to the user; data include the duration and time that the hit took place.

To determine whether or not the impact is likely to cause a concussion, Riddell is mining data it collected, along with research data from the NFL and NIH, to create probability curves. It has also set the threshold for a concussion at 98 g’s. In addition to telling a user the force of an impact, the Web application will provide information on the symptoms of a concussion, locate expert physicians and treatment options if a concussion has occurred, and suggest when it is safe for a player to return to play.

“Oftentimes an athlete will not show outward signs of concussions, so it is good to know if an athlete has received a severe enough blow to warrant one,” says Mike Goforth, the head athletic trainer at Virginia Tech. Goforth manages the system, which has been used by the football team for the past four years, and he says he is typically alerted two or three times a game that a player has sustained a hit over 90 g’s.

Brown University’s football team acquired the system last spring and is using it for the first time this season. Philip Estes, the team’s coach, says that the system is a valuable way to monitor athletes and find out who is taking dangerous hits so that he can adjust the tone and drills during practice. “It used to be if you didn’t feel good at night, it was called a lineman headache,” says Estes.

Simbex is also testing the technology in soccer headbands, ski helmets, and hockey headgear. Recently, the company received a $1 million grant from the United States Army to equip its combat helmets with the technology. “There has been tremendous interest in better understanding the biomechanics of brain injury following both blunt trauma and blast events in the military,” says Greenwald.

No helmet will completely prevent concussions, says Mark Lovell, director of the University of Pittsburgh Medical Center Sports Medicine Concussion Program. “But if we can create the technology to better monitor athletes and identify their risk levels, then we are at least doing some good.”

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