The lobby of the Intercontinental Hotel in the Buckhead section of Atlanta teems with conventioneers on the first weekend in June. Participants greet one another enthusiastically, hug necks and perform elaborate, nerdy handshakes. Some of the men are dressed like they just left a boardroom. Some are dressed like they came off a golf course. And some, such as the fire hydrant with arms wearing a sleeveless T-shirt, shorts and flip-flops, are dressed like they fell out of a frat house. They all carry freebies — in this case, two duffel bags, one blue, one white.

These are not ordinary men. Many are huge. A lot of them walk funny, almost shuffling, as if they couldn't stretch their legs all the way out even if they wanted to. Once they sit down, they stay down, unless they absolutely have to stand up — an arduous task from which the snaps, crackles and pops are audible. This is not an ordinary convention. It is a gathering of the NFL Players Association Retired Players, roughly 220 strong, and concussions are a hot topic.

Ken Burrow, a wide receiver for the Falcons from 1971-75 who is active in retired players circles, says he suffered one concussion in his football career. He says the concussion issue first came under discussion about 15 years ago. "In the last five years, it's been absolutely nonstop, with guys dying and getting disabled," he says. "Because of the sport, our life span is going to be less. I think about that. Of course I do. When you're younger, you think you're invincible. I did."

So do many current players. Football's rise to the top of the American sports world is built on the toughness of the players and the violence of the hits. Sitting out is for wimps who don't want their jobs badly enough. Walk it off, tape it up and get your butt back in there, Sally!

There's an old saying in the NFL, and it still applies today: You can play hurt, but you can't play injured. For years, a concussion either wasn't considered an injury or was misdiagnosed.

Many retired players suffering today were ignorant about concussions while they played. "We didn't know ..." is a common refrain in the Intercontinental. Today's players are better educated, yet many still willfully ignore the risks. In pursuit of glory, fame and fortune, they err on the side of danger.

Ricardo McDonald knows that attitude. He lived it in the NFL for eight years as a linebacker for the Bengals and Bears, and he sees it in players today. Standing in the lobby of the Intercontinental, McDonald still looks like he could play, though he hasn't since 1999. Intelligent, well-spoken and wise, he has enjoyed a successful postfootball career in business. Yet as a player, he succumbed to the pressures of the game by coming back too quickly from concussions — decisions that put him at risk.

He estimates he suffered "in the neighborhood of 20-plus" concussions in his career — at least seven times Bailes' threshold number. He says he once played in a game the same week doctors said his brain was 60 percent swollen — and then suffered a concussion on top of that.

He had an MRI recently, and the doctor told him he had the brain of an 80-year-old. He has headaches and memory loss. McDonald is 37.

Now McDonald, like many experts, says one key to avoiding long-term problems with concussions is not returning to action too quickly. Some say a player should never return to a game in which he suffers a concussion. But a six-year NFL study found 52 percent of players who suffer concussions return to play that day — including almost 25 percent who are knocked unconscious. According to the NFL's study: "Return to play does not involve a significant risk of a second injury either in the same game or during the season."

That conclusion counts only players who were cleared by a medical professional. But it still draws criticism from other experts, who say returning to action too soon has frightening consequences. There is evidence that returning too quickly from one concussion makes a player up to six times more vulnerable to suffer another. There also is evidence that a second concussion on top of a first that hasn't healed equals far more than just two concussions. Second Impact Syndrome can be fatal. "From 1980 to 1993, the National Center for Catastrophic Sports Injury Research linked 17 deaths in football to (Second Impact Syndrome), and many more deaths have occurred since then," writes Chris Nowinski in Head Games: Football's Concussion Crisis.

Kevin Guskiewicz, CSRA research director and a co-author with Bailes of the CSRA studies, told the Boston Globe: "It's a problem with the axons (of the brain) breaking down. If they don't get sufficient time to heal properly, they deteriorate to the point where they can't send the proper message from one axon to the next axon. It's like a series of extension cords. You're plugging them all together and one of them has a fray. There's electricity escaping from it, so the brain loses regulation of its blood supply, and there can be catastrophic injury from a second blow to the head."

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