How a 12-Ounce Layer of Foam Changed the NFL

Late in his team's game against the Green Bay Packers on September 15, Indianapolis Colts tight end Kylen Granson caught a short pass over the middle of the field, charged forward, and lowered his body to brace for contact. The side of his helmet smacked the face mask of linebacker Quay Walker, and the back of it whacked the ground as Walker wrestled him down. Rising to his feet after the 9-yard gain, Granson tossed the football to an official and returned to the line of scrimmage for the next snap.

Aside from it being his first reception of the 2024 National Football League season, this otherwise ordinary play was only noteworthy because of what Granson was wearing at the time of the hit: a 12-ounce, foam-padded, protective helmet covering called a Guardian Cap.

Already mandatory for most positions at all NFL preseason practices, as well as regular-season and postseason practices with contact, these soft shells received another vote of confidence this year when the league greenlit them for optional game use, citing a roughly 50 percent drop in training camp concussions since their official 2022 debut. Through six weeks of action this fall, only 10 NFL players had actually taken the field with one on, according to a league spokesperson. But the decision was easy for Granson, who tried out his gameday Guardian Cap—itself covered by a 1-ounce pinnie with the Colts logo to simulate the design of the helmet underneath—in preseason games before committing to wear it for real.

"I was pleasantly surprised that it didn't affect anything for me," the 26-year-old told WIRED a few days before facing the Packers in week two. "I thought, even if it looks kind of silly, it's worth it."

There is no ignoring the goofy aesthetics of the puffy, blobby Guardian Caps. The product's parent company, Guardian Sports, even has staff T-shirts that declare, —with LOOK GOOD crossed out. "Condom caps, mushroom heads—we've heard them all," says Erin Hanson, cofounder of Guardian Sports alongside her husband, Lee Hanson. "We just laugh, because we agree."

It can be tough to square the reality that the apparent future of football headgear resembles something out of a '60s-era sci-fi movie. But the fact that Guardian Caps are now allowed at all in games in the NFL—a league known for policing every inch of player equipment to protect its image—doesn't just speak to their lab-tested utility (even if published, peer-reviewed on-field data remains lacking). It also reflects the urgency of the moment for football at large.

The dangers of strapping on a helmet have never been clearer, given the link between repeated blows to the head—whether concussion-causing or not—and chronic traumatic encephalopathy (otherwise known as CTE, a brain disorder associated with cognitive issues like depression and progressive dementia that can only be diagnosed posthumously). Not coincidentally, the race to find answers has become faster and more lucrative than ever, between the NFL's funding of private research efforts and a rapidly innovating football headgear industry.

And at the center of it all, on the sport's biggest stage, is a literal mom-and-pop shop that, less than a decade and a half ago, was struggling to find a foothold in football as anything but a joke.

The story of the Guardian Cap starts in 1996, some 15 years before its invention. Settled in the Atlanta area with their then-four children, Erin, a former middle-school math teacher, and Lee, a chemical engineer, teamed up to found The Hanson Group, a business-to-business provider of chemical materials. Specializing in polyurethanes and epoxies, the company has since built, among other things, transparent body shields for the US Army, coatings of fuel tank plates for Boeing airplanes, and the outer layers of multiple brands of golf balls.

Then, in 2010, the Hansons were contacted out of the blue by an industrial designer named Bert Straus, who decades earlier had created a padded helmet attachment, the ProCap, that was worn in games by a handful of NFL players. Explaining that he was working on a new type of headgear, a hard-shell helmet with interior padding as well as a ProCap-esque soft shell mounted on top, Straus enlisted The Hanson Group to make the integral skin foam for this cushioned outer layer.

That winter, the trio traveled to a hotel ballroom in Manhattan and presented their product to NFL officials as part of a special league committee meeting on helmet safety. Even with live testimony provided by former Buffalo Bills safety Mark Kelso, who wore a ProCap for four-plus seasons in the early '90s, the attempt to convince the NFL of the potential of soft-shell technology was not well-received, the Hansons recall. "That lit a fire under us," Erin says.

Convinced that the best market opportunity lay with a one-size-fits-all option that could retrofit existing helmets at every level of football, as opposed to the brand- and model-specific ProCap, Erin and Lee struck out on their own. But the biggest difference in their eventual prototype had to do with how it was attached to the helmet in the first place: Its straps looped around the facemask and fastened to themselves, thereby loosely "floating" on top of the helmet rather than affixing directly via sticky-backed tabs.

The result was what the Hansons would later summarize in their United States patent request as a "protective helmet cap" with "a durable energy absorbing outer shell, which lessens the initial impact to the helmet ... [and] an inner surface that allows the outer shell to slide over the surface of a helmet thereby reducing forces applied to a wearer."

As development continued throughout 2011, Erin and Lee used money from The Hanson Group to send the caps away for independent drop testing—a longtime headgear industry standard in which a helmet-wearing dummy head is dropped onto a modular elastomer pad for measuring impact and shock absorption—at accredited sites like Oregon Ballistic Laboratories, ICS Laboratories, and the Southern Impact Research Center. They also shelled out for additional outside testing to ensure that the caps wouldn't affect neck torque and that they maintained a lower coefficient of friction relative to the usual football helmet's polycarbonate shell, to ensure that crucial "sliding" effect.

"Over the years, we've spent a couple hundred grand on testing, because we did so much before we put them on the field," Erin says. "The whole goal was to help, and it was certainly to not hurt, so we had to vet the product."

Initially branding themselves as POC Ventures—the acronym stood for "protecting our children"—the Hansons launched publicly at the January 2012 convention of the American Football Coaches Association in San Antonio. The goal was to sell caps and eventually attract an established sports equipment company to buy them out. Instead, Erin says, what few attendees dared approach their booth weren't exactly warm.

"You're sissifying football," Erin says, recounting one reaction.

"That's the stupidest thing in the world," Lee says of another.

But they soon found their first big believer. That year, at a medical conference in Destin, Flaorida, the Hansons met Jeffrey Guy, a physician for the University of South Carolina athletic department, who later looked at the caps' testing data and came away impressed enough for the Gamecocks football team—including future first-overall NFL pick Jadeveon Clowney—to start using them in their 2013 summer practices. Naturally it wasn't long before one of South Carolina's biggest rivals, Clemson, had placed orders too.

"It really was one team giving it a shot, and it just kept spreading," Erin says.

"That's the stupidest thing in the world," Lee says of another.

But they soon found their first big believer. That year, at a medical conference in Destin, Flaorida, the Hansons met Jeffrey Guy, a physician for the University of South Carolina athletic department, who later looked at the caps' testing data and came away impressed enough for the Gamecocks football team—including future first-overall NFL pick Jadeveon Clowney—to start using them in their 2013 summer practices. Naturally it wasn't long before one of South Carolina's biggest rivals, Clemson, had placed orders too.

"It really was one team giving it a shot, and it just kept spreading," Erin says.

Along the way, the Hansons abandoned the POC Ventures name after receiving a strongly worded letter from the Swedish cycling and snow sport helmet manufacturer POC, settling on Guardian and a halo logo as reflections of their religious faith. (They later switched the latter, too, to an angel's wing.) Their belief in their business mission was soon rewarded in April 2017, when the rechristened company was anointed as a winner of an NFL-sponsored research competition for protective football equipment, the HeadHealthTECH challenge, receiving $20,000 to fund future biomechanical testing for their Guardian Caps.

The Hansons were back in the door.

Technically speaking, Erin and Lee never saw their grand prize. Rather, the money ended up being routed directly to Biokinetics, an Ottawa-based laboratory that partners with the NFL for helmet testing. The results were then analyzed by Biocore, a biomechanical engineering firm out of Charlottesville, Virginia, that also acts as a league consultant for player equipment, including helmets.

At the time, the lone model of the Guardian Cap was the Guardian XT, a 7-ounce soft shell then already popular with a growing handful of elite college programs and hundreds of high school teams nationwide. But the results didn't measure up under lab conditions simulating the higher speeds and masses of professional football hits. "We didn't really find that it had much of an effect on the NFL impact environment," says Ann Bailey Good, a senior engineer at Biocore.

So the Hansons added an extra layer of padding to the XTs to create a beefier version, the 12-ounce Guardian NXT (with the N standing for NFL). It fared much better. For a 2021 published in Annals of Biomedical Engineering, five authors—Bailey Good, two Biocore colleagues, and two other engineers who regularly consult for the NFL Players' Association—subjected their crash dummy helmets to two main tests. The first involved hitting them with a pneumatic ram at speeds and points of impact that were determined in part through video review of concussion-causing plays among linemen during past NFL games. The second, for which the collision sites were picked to minimize face mask interaction and thus maximize helmet-on-helmet exposure, saw dummies with NXTs crash into each other with the aid of an electric belt-driven sled.

The results were assembled using the Head Acceleration Response Metric (HARM), a formula that Biocore, the NFLPA's engineering consultants, and several other researchers helped develop. for measuring the severity of an impact and how that correlates to helmet safety and performance. On average, as the study found , the addition of a Guardian NXT was reduced HARM by 9 percent over control helmets with no caps; by comparison, its competition in the study, the ProTech—a modernized version of the ProCap—only reduced HARM by an average of 5 percent.

Two aggregate scores were also calculated, by weighing test conditions based on how often those types of impacts occurred to actual NFL linemen and how many reported concussions were sustained due to those impacts. The NXT performed similarly well here, leading the study to conclude that the "Results ... suggest that using the GC NXT may reduce the head impact severity exposure for linemen."

"That's really when it started to become a thing in the league," Bailey Good says now.

The NFL soon brought the Guardian Cap to its Health and Safety Committee, a group of mostly team-, league-, and union-affiliated doctors, and to its Competition Committee, a rules-making body of coaches and team executives appointed by commissioner Roger Goodell. "We talked about the benefits we saw," says Jeff Miller, an NFL executive vice president overseeing health and player safety.

The next year, in 2022, the caps were rolled out for something of a trial period as the Competition Committee recommended that club owners vote to mandate them at preseason practices for select positions that according to league data had sustained the "most frequent head impacts" (offensive and defensive linemen, tight ends, and linebackers) during practice, Miller says. The mandate also only lasted for a four-week stretch when the "greatest density of concussions" had historically occurred—from the start of training camp to the second preseason game.

As the Guardian Caps gained more exposure thanks to the NFL's endorsement, increasing outside research helped shed more light on how they function. "I think it seems logical to most folks: If you cover your whole head in a massive pillow, maybe that'd help you more," says Nicholas Cecchi, a colead author on a 2023 study at Stanford University that in part performed similar lab impact tests on a version of the Guardian XT as Biocore did with the NXT several years prior. "But there's more to how it works that didn't seem intuitive."

In particular, Cecchi, who was a PhD student in bioengineering at the time of the study, cites the "sliding" effect produced by the Guardian Caps' design. "It really did seem like their main effectiveness was coming from the reduced surface friction on the exterior, and then also the decoupling of different layers," he says. In other words, the Guardian Cap isn't just a hat on a hat; the two-part, add-on system has its benefits.

When a helmet hit happens, says Cecchi, "you've got linear forces and rotational forces. Linear are going to be reduced by compression of the materials. Rotational forces will be reduced by the shearing and sliding of the different materials. The more that happens, the more it'll absorb the rotation, so less rotation will be experienced by your head.

"From the lab tests, it seemed very clear, in almost all scenarios, the Guardian Cap reduced the magnitude of those rotational accelerations, and other metrics linked to football-related injury risks, by a good amount."

Less conclusive is the data regarding how the Guardian Caps perform on the actual field. In addition to their lab component, Cecchi and his colleagues used instrumented mouth guards to look at helmet-to-helmet impacts sustained by a handful of linebackers on Stanford's football team in practices over two seasons: in 2019, when players wore bare helmets, and in 2021, when Guardian Caps were mandatory.

"We did not observe any significant reductions in any measure of impact severity after implementation of the padded helmet shell cover," the study concluded.

Similarly, in 2022, at the University of North Carolina, sensor-equipped helmets logged 14 full-contact practices among 10 players: five with Guardian Caps and five who opted to not wear them. As researchers later wrote in a late-2023 report for the International Journal of Environmental Research and Public Health , the coverings "did not affect head impact kinematic outcomes."

But these studies also categorized their on-field findings as "preliminary" and "pilot," respectively, in part due to the obvious small sample sizes. Here again, Biocore, backed by the NFL, is leading the way: According to Bailey Good, a paper unpacking the Guardian Caps' effect in their first two years of preseason practice use—in particular the league's touted 50 percent drop in concussions among linemen, tight ends, and linebackers, from an average of 35 in 2018, 2019, and 2021 to 18 during this last postseason—was submitted "a few months ago" and is currently being peer reviewed.

"We certainly considered other things like number of practices, practice intensity, et cetera," Bailey Good says. "But looking at the results that we saw in the preseason related to concussions, it was very promising."

Meaningful game data will take even longer to surface; the NCAA has yet to formally approve Guardian Caps for games at the college level, and while the National Federation of State High School Associations has allowed them in both practices and games since 2013, few examples of the latter exist. But the Hansons reject the idea that further testing is required to judge the credentials of their creation.

"We didn't just develop this three months ago—it's been out on the field for 12 years," Lee says. "I know it's anecdotal data, but what everyone tells us is that they feel better, they play better, and they have reductions in the numbers of injuries."

At the same time, the Hansons are sensitive to what they see as a common overstatement of the caps' capabilities. "We do not talk about reducing concussions," Erin says. "Science can only measure reduction of impact, reduction of forces. How that relates to brain injuries—there's a lot of unknowns that are still out there. Is it responsible to say this is the panacea for all? No, it's not going to fix everything.

"But do we know they're making a difference? Hell yeah."

More and more appear to be agreeing every day. Sitting in a conference room at the Guardian Sports offices in late August, Erin hits Play on a voice memo that a new client from Denver recently sent to Guardian's national sales manager. "This is a good one," she says, as a familiar southern twang comes through the speaker:

"Hey ... this is Peyton Manning calling ... I coach an eighth-grade youth football team ... and I was thinking I wanted to maybe ask about ordering some Guardian Caps ... I feel like it's the right thing to do."

Two football helmets bake in the afternoon sun atop a picnic table, one wearing a Guardian Cap and the other bare. The Hansons put them here, outside the entrance to their company's headquarters in a suburban business park northeast of Atlanta, as a practical demonstration of how the coverings, at 90-plus degree temperatures, can help insulate the helmet from outside heat. (Miller says that NFL testing has backed this up.)

Bearing an angel's wing logo on the front, the black-walled building is a 90,000-square-foot facility that Guardian Sports splits with The Hanson Group. Together it is a family operation in the most literal sense: Out of close to 50 employees between the two sides, 10 are members of the Hanson clan, including three of Erin and Lee's now-five children and two sons-in-law.

It took almost a full decade for Guardian Sports to become financially self-sustaining, and even longer to finish paying back The Hanson Group for the seven-figure costs of external lab testing and an early bulk purchase of more than 100,000 caps—that happened just last year. But the bustling scene suggests that business is good today. In the warehouse, towering stacks of Guardian Caps inventory have overtaken what was once an employee exercise area, like cubed cardboard weeds. In the loading dock, a truck drops off a fresh supply of green and maroon caps air-shipped from the company's factory in Dongguan, China after their stockpile of those colors ran out.

When it comes to the Guardian Cap, the XTs sell for about $70 at retail stores and online but less than $55 in group orders for teams, while the NXTs are only sold direct to teams at an average of $100 apiece. According to the company, some 77 percent of its overall sales happens in bulk. But only a small portion of that total—about 200,000 caps sold this year, the company projects—comes from the NFL's 32 teams, each of which typically stocks about 100 per season, replacing them every one to two years depending on the position and wear.

Not counting the cost of NFL testing through Biocore, though, Erin says Guardian has "never received a dime" directly from the league. Adds Lee, "They own the data too—only when they publish it, we get to see it." But the benefit of having a public stamp of approval in the shape of the NFL shield is obvious.

"We had to have outside validation, and that's what the NFL has done for us," Erin says. "You can't put a value on the marketing that you get from your product. But they're not writing us checks, that's for sure."

On the flip side, the company has already done more for the NFL than its owners ever imagined. "The last thing we ever wanted to be in was the customization business," Erin says, referring to the nine months it took to create the Guardian Cap pinnies that matched the helmets of every team so they could be worn in games this season. Between designing the concepts, conducting testing through Biocore, enlisting two college teams (Colorado and Georgia) to pilot them at spring practice, and ensuring the proper pantones and logos—all but four sent the initial batch back, including the Carolina Panthers, who requested that the silver pinnie "sparkle more," Erin says—every step was geared toward aesthetic goals. Asked if it was a necessary headache to collaborate with the league, Lee replies immediately: "Yes."

Adds Erin, "If it allows a player who feels like he's getting the same benefit in a game as in practice, then it's worth it."

To this end, Guardian recently completed production on versions 2.0 of both the XT and NXT caps, featuring flatter, more helmetlike exteriors onto which teams can iron on logo decals. "The barriers to gameplay, I think, are the lack of gameplay testing data and the aesthetics," says chief operating officer Jake Hanson, Erin and Lee's son. "The more we can get at those with the 2.0s, the better."

Given the relative lack of caps in NFL stadiums so far this season, it seems unlikely that they can catch on as a widespread gameday add-on. But even their future in practice remains uncertain. "The Guardian Cap could be a transition as we move from good helmets to better helmets, as that technology continues to improve," Miller says.

That time might already be here: Entering this season, Biocore approved six new helmet models that would allow any player who wore one to be exempt from the Guardian Cap practice mandate. And more than 200 players have already taken advantage of the carve-out, "an unprecedented rate of adoption for a new piece of equipment," NFL chief medical officer Allen Sills said on a media call in early October.

To both the lab and the league, the decision here boiled down to incentivizing players to use better-performing helmets.

"Decreasing benefit to wearing it, to the point where some of the technology that the helmets have now made the addition of a Guardian Cap on top of it of less utility than it would've been with one of the other helmets," Miller says, when asked why the coverings were made optional at all. "And eventually you get to the plus-minus of, well, you're adding a bunch of ounces to your head."

Should the Hansons buck the odds once more and become a bigger NFL game-day presence down the line, it might be former players turned coaches leading the way. Like Manning. Or former running back and fellow Hall of Famer Jerome Bettis, an early proponent who bought Guardian Caps for an Atlanta-area youth football league that he and ex-Pittsburgh Steelers teammate Tim Lester started for their sons in the mid-2010s.

"You'll get these comments about, how can you put these things in the game?" Erin says. "Then you have interactions with people who are actually living the repercussions, it's a whole different thing."

As for one of the few current players to have embraced the Guardian Caps in games, the Colts' Granson doesn't see himself stopping anytime soon.

"A big hit's gonna happen—that's the inevitability of the game," he says. "But if I can reduce the contact of the little hits, then that'll spare me down the road."