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."