Updated

By Scott Malone

BOSTON (Reuters) - As Americans grow more aware of the risk of brain injury tied to football - the country's most popular sport - players and coaches are experimenting with the latest technology in a bid to make the game safer.

Advances in training have led to bigger, faster players who have made the high-impact sport more dangerous, particularly at the college and professional level.

Football fans have witnessed devastating instances of concussion-related brain damage and even death in players as young as high-school age. They include 16-year-old Ridge Barden, 16, who collapsed after a hit in a game in Phoenix, New York last October and later died at a hospital.

Gordon Powers, the coach of the Model High School football team in Rome, Georgia, saw how important it was to do more to protect players two seasons ago. He was sending more team members to the bench who were showing signs of concussion.

"We were losing a lot of players that couldn't play in the game on Friday night," Powers recalled. "We would do a drill and if a kid got up real slow, was a little groggy, here comes the trainer (who would say) ‘OK, that kid's going to be gone for a week.' We wanted to do something about it so the kids could continue to compete."

Model High last year became one of the first high schools to experiment with a helmet cover developed by The Hanson Group of Alpharetta, Georgia and Protective Sports Equipment of Edinboro, Pennsylvania. The cover, dubbed the Guardian, has 37 gel-filled pouches that fit over a helmet and cushion against helmet-to-helmet blows that are so dangerous that the NFL aggressively penalizes them.

Powers' team wore the helmet covers only in practice because they weren't sure local league rules would allow them to be worn in games. Hanson Group owner Lee Hanson said even that helps.

Hanson sent out 600 samples for teams and players to test during the 2011 season and this year aims to sell about 200,000 of them, for about $60 a piece. None of the players that tested the Guardian last season reported a concussion, Hanson said, and testing by Wayne State University in Detroit found the product reduced the amount of shock felt through a helmet.

REASON FOR CONCERN

Research has shown that more than 4 million youth players are at risk. A 2011 study by Nationwide Children's Hospital found football players aged 6 to 17 are treated in hospital emergency rooms for about 8,631 concussions each year. Many more concussions may go unreported.

A separate study by the hospital found that football was responsible for almost half of reported concussions among high school athletes, above ice hockey, soccer and other sports.

One in five parents say they worry a great deal about their child suffering a concussion from playing football or another sport, according to a 2011 survey by Safe Kids USA, a non-profit group that aims to prevent childhood injuries.

Parents are also faced with the reality that even the best helmets available do not eliminate the risk. Laura Mason learned that lesson when her son, Zack, was diagnosed with a concussion in 2010 from a game in his sophomore year at Westborough High School in Westborough, Massachusetts. He was wearing a new helmet that she bought for him.

Her son missed much of the next three weeks of school, and didn't return to his full academic schedule for about four months. He skipped football season in his junior year, but intends to return to the game in the fall for senior year.

"I'll let him do it," Mason said. "I know my son. He's not a real rough player, he tends to step back a little bit more, so I'm OK with it."

MULTI-SECTIONAL HELMET, BUILT-IN ICE PACK

At the pro level, the NFL allows players to choose any helmet they want that meets the standard set by the National Operating Committee on Standards for Athletic Equipment, a voluntary industry group.

"We want our players to wear the best available equipment using the latest technology," NFL spokesman Brian McCarthy said in an e-mail. "We are encouraging all helmet manufacturers to continue to improve helmets."

The NFL's helmet sponsor Riddell regularly tweaks the padding and design of its equipment, while Xenith LLC's line of helmets use air-filled pads rather than foam. Other companies are testing more dramatic changes.

A New York-based startup company called Thermopraxis and Schutt Sports - the largest producer of football helmets - are working on a product called the Thermocrown.

The effect would be similar to applying an ice pack.

"A coach can initiate this in seconds," Rozental said. "The concept can buy time, up to four to five hours, to allow the patient to be transported from the field" to a hospital.

Independent industrial design engineer Michael Princip is working on the Bulwark, which features multiple plates on the helmet's exterior, instead of the single-piece design common today. It is intended to dissipate the impact of big hits and more frequent, smaller ones that are a part of the game.

Any of these designs would represent the biggest change in football helmet technology in decades. Helmets started as soft, leather caps in the early the 20th century, then gave way to plastic shells with foam padding and facemasks in the 1950s.

CLEAR RISK, MULTIPLE SOLUTIONS

Research by Boston University's Center for the Study of Traumatic Encephalopathy, found evidence of the disorder in the brains of more than 50 deceased athletes. One of them, former NFL player Dave Duerson, shot himself in the chest in February 2011, leaving behind the request that his brain be studied.

While manufacturers and other inventors look for ways to make helmets safer, most admit equipment is not the only answer to prevent a worsening phenomenon.

The NFL has tweaked the rules intended to limit concussions. They range from changes in game play, including moving the kick-off line forward by five yards, to telling teams to keep players off the field if they show memory problems.

But U.S. football helmet testing standards have not significantly changed since 1980, when tougher rules on impact resistance intended to limit skull fractures took effect.

Hundreds of former players have sued the NFL and Riddell, alleging the league knew or should have known about the long-term dangers of concussion but allowed them to play anyway.

Fit is a challenge since most players wear helmets owned by their schools or teams that have been handed down for as many as 10 years. Helmets can cost from $100 for youth-sized models to as much as $375 for high-end ones worn by college players. School programs can usually afford to replace helmets only every few years.

"We're a big believer that every kid should have his own helmet," said Vincent Ferrara, a former Harvard University quarterback who founded Lowell, Massachusetts-based Xenith in 2004. The company charges $329 for its top-of-the-line X-1 helmets.

"We've been accused sometimes of being self-serving," he said. "But we look at all the other things that parents buy for their kids, including their sporting equipment, and we think football helmets should be right up there."

As a player, Ferrara suffered a concussion in the seventh grade that led his mother to pull him from the sport for a full season. After that, he was reluctant to admit when he was hurt.

(Reporting By Scott Malone; Editing by Michele Gershberg and Paul Simao)