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The cold case of Patrick Mahomes’s cracked helmet

Kansas City Chiefs quarterback Patrick Mahomes continued to play with a broken helmet until the refs stopped the game, and he put on a replacement before absorbing another hit. (Reed Hoffmann/AP)
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A hunk of polycarbonate plastic came flying off Patrick Mahomes’s helmet during an NFL playoff game Saturday night, a bizarre and high-profile moment with an easy, if uncertain, explanation: “I’m sure it had to do with it being really cold,” Mahomes told reporters after the game.

The Chiefs beat the Miami Dolphins with temperatures in Kansas City hovering around minus-4 degrees at kickoff, making it the fourth-coldest game in NFL history. There will be more shivering in the divisional round. The Detroit Lions play in a dome, and Santa Clara, Calif. will be spared the frigid conditions felt in most of the country. But both Texans-Ravens and Chiefs-Bills will be played in freezing cold, with the forecast calling for temperatures of 22 degrees at kickoff in Baltimore and 18 degrees in Buffalo.

The crack in Mahomes’s helmet raised an obvious question: Should players worry about the durability of their helmets in the extreme cold? Barry Miller is the director of outreach at the Virginia Tech Helmet Lab, which tests and grades helmets of all kinds. Though the cold affects materials used to make helmets, Miller said Mahomes’s helmet break should be seen as an isolated misfortune, not a warning to other players.

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“I would say your helmet is going to perform pretty darn well regardless,” Miller said. “I mean, it was kind of a fluke. No one else cracked their helmet. We’ve had season after season in cold weather, and this doesn’t happen very often. I wouldn’t worry about it.”

The reason behind Mahomes’s broken helmet remains a mystery, and the NFL wants to solve it. The league sent Mahomes’s helmet to Biocore, a research lab in Virginia that conducts helmet testing for the NFL, for “analysis to understand what took place,” NFL spokesman Brian McCarthy said in an email.

The play itself appeared ordinary. As Mahomes scrambled toward the goal line midway through the third quarter Saturday night, Dolphins safety DeShon Elliott collided with him head-to-head. The front of Mahomes’s helmet cracked, and a fragment of the red outer covering broke off and floated to the ground.

“I didn’t know what happened in the moment,” Mahomes said. “But I got in the huddle, and everybody was telling me. And I was like ‘I got y’all, but I’m not coming out the game.’ ”

Mahomes’s incident was unusual even within the rare universe of helmet cracks. Mike Oliver is the executive director of the National Operating Committee on Standards for Athletic Equipment, which certifies helmets for use. He has seen a lot of helmets break, but he could not recall a piece fluttering off one.

Usually, Oliver said, a crack forms near a hole that’s been drilled to screw in the face mask, and it’s so small it would go unnoticed without close inspection — and wouldn’t be likely to affect the helmet’s performance. “The way the helmet broke is something I don’t think I’ve seen anywhere,” Oliver said.

Why did Mahomes’s helmet crack? Miller said there are “endless” possibilities: The polycarbonate blend of that helmet’s shell may have been subtly compromised. That precise spot could have been exposed to another hit that weakened the helmet in an unnoticeable way. The hit could have come at just the right angle with just the right force. “Things happen,” Miller said.

One factor, of course, stood out. Mahomes may or may not have been correct that the icy temperatures contributed to the busted helmet. Cold causes materials to stiffen and become less pliable, which makes them more vulnerable to cracking rather than bending when a high-energy force is applied.

“Like your garbage can or Tupperware or whatever — it cracks real easy under super cold temperatures,” Miller said. “A helmet is made out of a little different materials, but it is susceptible to extreme temperatures.”

NOCSAE tests helmets’ performance in extreme heat but not extreme cold. The reason is straightforward: Heads generate a tremendous amount of heat. Even in extreme cold, a helmet in use stays warm. (There are tests to make sure the outer shell can release heat so players in hot temperatures don’t overheat.) Oliver doubts the cold contributed to the crack of Mahomes’s helmet, because Mahomes’s helmet wouldn’t have been cold.

“There have been a lot of games played at zero and below,” Oliver said. “I’ve not seen any evidence that helmets are more likely to fracture or break at those temperatures.”

Mahomes wears a version of the VICIS Zero2 model. VICIS parent company Certor Sports, which also owns the football helmet manufacturer Schutt, tests helmets’ performances in extreme cold, Certor Sports CEO Jeremy Erspamer said in an email. “We will obviously be looking more into this to determine what additional advancements can be made in this area,” Erspamer added.

Virginia Tech’s evaluation system rates the VICIS Zero2 as the third-best helmet at protecting against concussions. It is, Miller said, an “extremely good” product — and the incident Saturday night wouldn’t change his opinion.

“Just because the helmet cracks doesn’t mean it didn’t perform its job,” Miller said. “Now, the next hit, it probably wouldn’t do its job, because it’s cracked. But for that given impact, maybe it did dissipate energy accordingly, but the shell cracked in the process of absorbing energy.”

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Most helmets made for purposes other than football — bike helmets, equestrian helmets, snow-sport helmets — are classified as single-impact. They are designed to crack and crumble upon high impact as a way to disperse the energy from an accident, like a crumple zone in a car.

It would be impractical and financially unfeasible for a football helmet to break on impact, which makes it a multi-impact helmet: It must be designed to attenuate energy without breaking. Even when Mahomes’s helmet broke, though, it worked.

“Some engineers would argue slightly better,” Oliver said. “Because when you have things that permanently deform in the course of an impact, those things are taking up energy that otherwise would have been transferred to the head.”

The VICIS Zero2 is designed differently than other football helmets. It has a rigid inner shell made of similar material to the outer shell of traditional helmets. That layer is covered with rubberlike material that absorbs impact. The final layer — the part of Mahomes’s helmet that broke — is a relatively flexible outer shell.

“While we never want to see an event like this with an athlete wearing our helmets, the multi-layer technology of the helmet did exactly what it is designed to do: protect Patrick Mahomes,” Erspamer said. “We will gladly trade a cracked shell for the complete protection of the athlete allowing them to continue playing the game they love.”

Oliver said the only risk Mahomes’s broken helmet posed was another player getting cut by the sharp edge of the hole in Mahomes’s helmet.

“A hard-shell helmet, if it broke that, I’d be concerned,” Oliver said. “That would mean all the force was not transmitted in a wide area. But because VICIS approaches it in a different way, I don’t think you’d reach that same conclusion.”

Officials paused the game shortly after Mahomes’s helmet cracked and allowed him time to pull on a replacement. When he retrieved the spare, he discovered the cold presents one certain helmet-related challenge.

“We got to talk about where we store the backup,” Mahomes said. “Because it was frozen.”