More than a decade ago, the sports equipment manufacturer Riddell was developing a highly anticipated new football helmet designed to reduce players' risk of concussions. The helmet was ambitiously called the Revolution. It would become the most widely used helmet in the NFL and earn millions in sales to players in college, high school and youth leagues.

But back in 2000 the company received a warning: A biomechanics firm hired first by the NFL and later by Riddell to test helmets and study head injuries sent the company a report showing that no football helmet, no matter how revolutionary, could prevent concussions.

In fact, the report stated, even a helmet that passed the industry safety standard for protection against skull fractures and other severe head injuries could leave a player with a 95 percent likelihood of receiving a concussion from a strong enough blow.

Yet the report, made public during a recent Colorado lawsuit, did not deter Riddell from marketing the helmet as protection against concussions. Riddell promoted the Revolution by saying that players who wore it were 31 percent less likely to suffer a concussion -- a figure criticized as an exaggeration by leading experts on head injuries and some members of Congress.

Riddell is being sued by thousands of former NFL players as a co-defendant in the major lawsuit against the league. The plaintiffs charge, in part, that Riddell failed to warn them that its helmet would not protect against concussions. Last month, in the Colorado case, Riddell was found liable for $3.1 million out of a total of $11.5 million that was awarded to the family of a young man who was seriously injured after a concussion in a high school football practice.

The Colorado jury cleared Riddell of a charge that its helmet had a design flaw. But it found that the company had failed to adequately warn players of the risks of concussion. Riddell said it plans to appeal the verdict.

"While disappointed in the jury's decision not to fully exonerate Riddell, we are pleased the jury determined that Riddell's helmet was not defective in any way," the company said in a statement. "We intend to appeal this verdict, and we remain steadfast in our belief that Riddell designs and manufactures the most protective football headgear for the athlete."

Frank Azar, a lawyer for the plaintiffs in the Colorado case, said that the outcome could have implications for the larger suit by NFL players. "What it proves is that Riddell knew for sure in November of 2000 that they had a problem with their testing of these helmets and they didn't disclose it to anybody," he said.

Chris Withnall, who wrote the 2000 report to Riddell as the senior engineer at the Ottawa-based biomechanical firm Biokinetics, said recently, "No helmet can prevent a concussion. Full stop."

The push to create a better helmet

Concussions in sports, especially football, have become the focus of intense study and debate. But they are still not well-understood injuries. Two players with the same medical history can receive the same kind of blow and respond differently. Building equipment to minimize the dangers requires overcoming many obstacles.

Rep. Steve Cohen, D-Tenn., views an older NFL football helmet during a House Judiciary Committee hearing in 2010. The committee would later question NFL football commissioner Roger Goodell about the league's approach to concussions. AP Photo/Paul Sancya

Concussions are often caused by a combination of what are called "linear" and "rotational" accelerations. In linear acceleration, the head is moving in a straight line when it suddenly stops, as in many car accidents. During rotational acceleration, the head is twisting or struck from one side, which can cause a shearing effect on the brain. While it is known that rotational acceleration may be more correlated with concussions, it is not known just how much will cause a concussion. Without a threshold, it's impossible to create a test that will measure the risk of concussion.

"Nobody knows how to make a helmet that prevents a concussion," Withnall said. "We know [the research is] moving in the right direction but there are still these rotational motions that we can't control."

Riddell designed the Revolution helmet with the help of Biokinetics, which was also working with the NFL's Minor Traumatic Brain Injury (MTBI) Committee.

The NFL formed the MTBI Committee in 1994 in response to high-profile concussions. One of the committee's goals was to improve understanding of the biomechanics of concussions, and to use that information to engineer a concussion-resistant helmet. (The committee was disbanded in the wake of pressure generated by a 2009 Congressional hearing.)

The committee and Biokinetics studied concussions in the NFL over a five-year period, and by 2000 had focused on 12 on-field collisions, nine of which had resulted in concussions.

Riddell subsequently hired Biokinetics for $500,000. Riddell has been the NFL's official helmet maker since 1989. NFL players can choose other helmet brands or models of Riddell helmets, but teams are given incentives to get the majority of their players in Riddell helmets. When Biokinetics and Riddell teamed up, the idea was to apply the findings of the NFL's research to its new helmet.

In November 2000, as Riddell developed the Revolution helmet, Biokinetics sent the company the report concluding that existing helmets -- and the safety tests used to regulate them -- were designed to prevent catastrophic head injuries like skull fractures, but not concussions. Modern helmets easily pass the safety tests. But, the report showed, that did not mean they could protect against concussions.

How do you measure concussion protection?

Manufacturers rely on safety tests created by the National Operating Committee for Standards on Athletic Equipment (NOCSAE), an independent standard-setting body that does not conduct studies but provides grants to those who do. The group is funded with licensing fees collected from helmet companies and its board is drawn from both industry representatives and sports medicine experts and scientists.

NOCSAE rates helmets numerically on a "Severity Index." Severity Index scores reflect how well helmets absorb the energy from an impact by measuring the effects on the head and brain: the higher the score, the greater and potentially more damaging the effects. Helmets that score below 1200 pass the tests.

In the 2000 report to Riddell, Biokinetics wrote that scores well below 1200 still carried a high risk of concussion. "A concussion is almost certain to occur at [Severity Index] levels half that of the current NOCSAE standard," the report said.

The NFL formed a committee in 1994 in part to try to better understand the biomechanics of concussions, and to use that information to engineer a concussion-resistant helmet. AP Photo/Mark Duncan

Elsewhere in the report, Biokinetics reported that a player wearing a helmet that scored 291.2 during an impact -- well within the safety threshold -- would have a 50 percent probability of suffering a concussion. A helmet that scored 558.9 during the same impact would carry a 95 percent risk of concussion.

In early 2011, an independent lab called ICS Laboratories was hired by Schutt, Riddell's primary competitor, to compare the performance of different helmets. Taking an average of the results at different test points, the lab found that Riddell's Revolution scored a Severity Index level of 444.3 at 72 degrees of angle, 448.5 at 105 degrees and 512.3 at 120 degrees, according to a report obtained by FRONTLINE and ESPN.

Compared with results for other popular helmets available at the test time, the Revolution fell in the middle of the range. Riddell declined to confirm the scores.

Mike Oliver, the executive director of NOCSAE, said the group's standard does limit linear acceleration -- one of the forces behind concussions -- but is not designed to rate protection against concussions. "That was never the intent behind the standard," he said, because there is not adequate science to create a standard for concussions prevention.

In the Colorado trial, Riddell's senior vice president for research and development, Thad Ide, testified that the NOCSAE test was utilized to guide the development of the Revolution. Riddell also incorporated results from another test, created by Biokinetics, called the Pendulum Test. The test was designed around the same time as the Revolution and was an early attempt to measure rotational acceleration.

Asked in the trial about the design influences and criteria that went into creating the Revolution, Ide responded, "Yes, all of the usage requirements and -- and more specifically the NOCSAE test requirements."

Riddell declined to make Ide or another representative available to answer questions for this article. In an emailed statement, the company said it is "proud of the Riddell Revolution helmet." The statement also said that "unique innovations" that came out of the Biokinetics work are still found in Riddell helmets, and have been used by other helmet makers.

J.C. Wingo, who was president of Riddell from 1991 to 1993 and later worked for Schutt, said in an interview that he was surprised by the Biokinetics memo. Wingo has worked in the football equipment industry for more than 25 years, and said he had never seen a report before indicating that a helmet that received a passing grade on the NOCSAE test might still carry a high risk of concussion.

"It's kind of surprising that Riddell has known this since the year 2000 and that they didn't go to NOCSAE and say we need to really look at the severity index standards," said Wingo. "I was really taken aback by it."

Oliver, who has been with NOCSAE since 1995, said he had not seen the Biokinetics report or any specific figures that tied passing scores with probabilities of concussion. But he wasn't surprised by those findings, since the standard deals only with catastrophic injuries, not concussions.

In the past few years, NOCSAE has been criticized for its reliance on a test that did not do more to address concussions. "We would love to come up with a standard that would directly address concussion. That's what we're looking for," Oliver said in an interview. "But to do that there has to be significant science behind it to make the change." Oliver also pointed to the more than $7 million NOCSAE has given in grants in the past decade to study the issue.

Marketing the Revolution

After its release in 2002, the Revolution quickly became popular among NFL and youth players. The Indianapolis Star wrote: "The product of years of research, Riddell's 'Revolution' is being marketed as a first-of-its-kind helmet, one designed to reduce the risk of concussions. 'We know there are more than 100,000 concussions due to football in the United States every year,' said Thad Ide, vice president of research and development for Riddell, the official helmet supplier of the NFL. 'We hope we can reduce that number.'"

After the Revolution hit the market, Riddell hired some of the premier concussion researchers in the country at the University of Pittsburgh Medical Center (UPMC) to study the new helmet. Ide was also an author of the study.

The UPMC study looked at three high school football seasons at 17 schools in Western Pennsylvania, comparing the Revolution with standard helmets, which had previous use. They tracked the number of concussions based on which helmet the players were wearing, and tested recovery times from blows to the head using ImPACT -- a computerized neurocognitive test battery developed by the UPMC researchers, neuropsychologists Mark Lovell and Michael Collins and neurosurgeon Joseph Maroon.

The findings of the study, published in the February 2006 edition of Neurosurgery, became a point of controversy. According to Riddell, the study found that athletes wearing the Revolution had a 31 percent decreased risk of concussion. But the UPMC authors disputed that claim.

Research on football helmets has shown that no helmet can prevent all concussions. AP Photo/Mark Duncan

Maroon, who with Lovell also sat on the NFL's MTBI Committee, said his team at UPMC took issue with the way that Riddell characterized the findings. The article had actually stated that wearing the Revolution was associated with "approximately a 31 percent decreased relative risk and 2.3 percent decreased absolute risk for sustaining a concussion in this cohort study." Absolute risk is a more accurate reflection of risk levels.

In an interview with FRONTLINE and ESPN, Maroon said that by focusing solely on the larger number, which referred to a relative decrease in risk, Riddell exaggerated any benefits. "There was very significant concern," Maroon said. "And our community relations public relations department notified Riddell that this data should not be use as a marketing ploy or marketing tactic from a scientific paper that was done not for those purposes."

A draft press release from Riddell, provided to FRONTLINE and ESPN by UPMC, shows that UPMC's press office attempted to edit Riddell's claims in the release. But their recommendations were not followed.

The original headline of the release said: "Research Shows Riddell Revolution Football Helmet Provides Better Protection Against Concussions." UPMC deleted that and wrote, "can't say it provides better protection …" The original release asserted that, "the Revolution football helmet provides significantly better protection against concussions." UPMC deleted that, and wrote, "We can't say this."

And where Riddell had written that athletes wearing the Revolution were 31 percent less likely to suffer a concussion, UPMC inserted the words "in terms of relative risk."

Some changes that UPMC recommended were used in the final version of the press release. But the changes listed above were not incorporated.

There were also other concerns that rankled critics of the study.

Dr. Robert Cantu, a neurosurgeon and leader in the field of sports-related concussion research, wrote a comment published in Neurosurgery noting that the study contained a "serious, if not fatal, methodological flaw." Because the study did not include the age of the non-Riddell helmets, Cantu wrote, it was impossible to compare the two. No matter what model of helmet, he said, the older it is, the worse it performs.

Additionally, he wrote, the NFL's research that was used as the foundation for the Revolution focused on only a small percentage of the NFL's concussions, and only those of a certain type. "Although this new helmet design may be an improvement for those 3 percent of concussions," Cantu wrote, "I have no way of knowing whether it is an improvement for the other 97 percent of concussions that could not be studied."

Cantu has sat on the board of NOCSAE since 1994 and serves as its vice president. One of his final comments on the Revolution/UPMC paper echoed the points made in Biokinetics' 2000 memo to Riddell. "We currently know that no helmet tests to a severity index even double what would be needed to prevent concussion," Cantu wrote. "Therefore, I would not expect any of the current helmets to have a dramatic impact on concussion prevention."

Oliver, of NOCSAE, said he is not aware of any peer reviewed article that points to a specific Severity Index level that is more protective from concussions.

As Revolution sales climbed -- more than 2 million were sold between 2002 and 2008 -- the helmet company's claims caught the attention of Sen. Tom Udall (D-N.M.). In January 2011, Udall sent a letter to the Federal Trade Commission about what he called misleading safety claims and deceptive practices in the helmet industry. He singled out Riddell's 31 percent claim, and wrote that he was particularly concerned about the marketing of the youth Revolution helmet.

In a letter to the Consumer Product Safety Commission, Udall also pointed to NOCSAE and concerns that its standard does not directly address concussions.

"This voluntary industry standard does not specifically address preventing concussions caused by less severe blows or by rotational acceleration," Udall wrote. "The CPSC has a responsibility to ensure that football helmets meet safety standards that address concussion hazards and reflect the state of the art in helmet technology."

Currently, the Institute of Medicine of the National Academies of Science is investigating sports-related concussions in youth. Udall and Sen. Jay Rockefeller (D-W.V.) plan to introduce a bill that would endorse recommendations regarding helmet safety that result from the investigation.

Before this year's Super Bowl, the NFL announced its support of the bill. Oliver said he has seen a draft of the bill, and he expects that NOCSAE will endorse it as well, provided it does not change drastically.

Sabrina Shankman is a reporter for PBS Frontline.