Attorneys suing the NCAA over its handling of head injuries asked a federal judge Friday to let them expand the lawsuit nationwide to include thousands of plaintiffs in a case they contend could change college sports forever.

The motion seeking class-action status was filed in U.S. District Court in Chicago, where the original lawsuit was filed two years ago on behalf of several former athletes, including former Eastern Illinois football player Adrian Arrington. His attorney, Joseph Siprut, said he doesn't want to see the demise of college contact sports, including football, but safety is paramount.

"If changes aren't made, the sport is going to slowly die," he said. If they can't be reassured football is safe, parents will stop their kids from playing "and when the talent well dries up, that's how the sport dies."

The NCAA late Friday did immediately respond to an email seeking comment.

Concussions have become a major issue in sports in recent years. The NFL, NHL and college football, among others, have implemented stricter rules on hits to the head and player safety. But the NFL is mired in a lawsuit involving more than 4,000 former players seeking millions of dollars for problems they blame on head injuries during their careers.

The NCAA could wind up in a similar situation.

Attached to the class-action request is a report for the plaintiffs by a leading authority on concussions, Robert Cantu, who cites an internal NCAA survey from 2010. He said the NCAA found that nearly half of the college trainers who responded indicated they put athletes showing signs of a concussion back in the same game.

"It is well settled in the scientific community that an athlete must never be returned to play on the same day after a concussion diagnosis," said Cantu, who is medical director of the National Center for Catastrophic Sports Injury Research in Chapel Hill, N.C.

The plaintiffs say the NCAA was lax in establishing a clear policy about dealing with concussions, leaving key decisions to individual schools or leagues.

"That is tantamount to doing nothing or even worse," said Siprut. "It creates the misperception that they have taken adequate measures when they haven't."

Arrington contends he suffered "numerous and repeated concussions" at Eastern Illinois, which is perhaps best known as the alma mater of Dallas Cowboys quarterback Tony Romo and Saints coach Sean Payton. Arrington is seeking unspecified monetary damages and changes in policy including the establishment of a long-term medical monitoring program for injured athletes and new concussion guidelines for schools and coaches.

The lawsuit accuses the NCAA of failing student-athletes and "choosing instead to sacrifice them on an altar of money and profits" by neglecting to adopt stricter standards. Responding to Arrington's lawsuit in 2011, the NCAA said it found "gross misstatements" and said the governing body has been "concerned about the safety of all of its student-athletes, including those playing football, throughout its history."

The NCAA has taken recent steps to beef up awareness of how to treat possible head injuries, from legislation and outreach efforts to new rules on the playing field. Earlier Friday, the NCAA said it was awarding a $399,999 grant to fund a study into the long-term effects of head injuries in college sports.

Last fall, the NCAA said the rate of football-related concussions has remained steady over an eight-year period _ with 2.5 concussions reported for every 1,000 game-related exposures in 2011. The NCAA says there are estimates that between 1.6 million and 3.8 million concussions occur in sports and recreation-related activities every year.

The concussions lawsuit is just one of several legal headaches for the NCAA. On Thursday, six current college football players were added as plaintiffs to a high-profile antitrust lawsuit that claims the NCAA owes billions of dollars to former players for allowing their likenesses to be used without compensation. The federal judge in that case is still mulling whether to turn the lawsuit into a class action.

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