Caution Lights

THERE ARE plenty of big hits in an Arena Football League game, and this season it has been a little easier to tell who has been on the receiving end of one. Each week about 40 AFL players have been outfitted with something called the Shockometer, a sensor attached to the back of the helmet. If a player sustains a jarring hit (one registering at least 98 g's of force, or roughly what you'd feel jumping headfirst off a 13-foot ladder), then the light on the Shockometer turns from green to red, indicating that the player may have sustained a concussive blow and should be checked out.

Concussions are notoriously difficult to diagnose; players who get them either aren't aware they've been hit especially hard or don't want to show what might be perceived as weakness by coming off the field. "We wanted to develop a warning system that would be fast and able to measure the impact of these collisions," says Dave Rossi, chief marketing officer of Schutt Sports, which makes the Shockometer and hopes to market it from the pros down to youth leagues. "A red light doesn't mean the player automatically has a concussion, but it does alert the team that this guy needs to be checked out."

The Shockometer remains a work in progress and will be used in a few AFL games each week. (The league hasn't released any data on how many red-light hits have been delivered.) So far, the players who have worn the device have no complaints. "It's completely unobtrusive," says Georgia Force quarterback Chris Greisen. "Players take concussions seriously, and it's good to know that the league and Schutt are looking out for our safety. I'm glad it's being tested."