Helmet, sure, but who would wear a mushroom?
Bicycle safety experts urge new safety designs to include shock-absorbant materials
Whether helmet use should be mandatory for bicycle riders is a heated topic.
You’re undoubtedly better off wearing a helmet if an accident occurs, and the importance of wearing a helmet increases with the significance of the accident.
But while helmets have come a long way since the strappy leather head coverings some cyclists wore before the 1970s, they still don’t do much to protect us from concussions.
Helmet experts are calling for radically new designs to improve safety.
Studies have found that in an accident, you’re much less likely to suffer a severe brain injury if you’re wearing a helmet than if you’re not, but your odds of experiencing minor brain trauma are similar. That’s because modern helmets are lined with hard foam.
The design can withstand a serious impact, protecting your skull from fracturing against a hard surface such as pavement, but the rigid foam doesn’t absorb as much energy as a softer liner, such as those found in football helmets.
The best protection for a bicyclist would be a helmet made from a softer material thick enough to absorb any impact, but “nobody wants to bike around with a mushroom on their head,” said Mehmet Kurt, who studies head injury prevention at the Stevens Institute of Technology in Hoboken, N.J.
The No. 1 reason people don’t want to wear a helmet relates to self-image — how cool it looks or whether it will cause helmet hair, he added.
Consumer preference has often driven helmet design, and not always in the direction of safety.
Randy Swart, director of the Bicycle Helmet Safety Institute, a non-profit based in Arlington, Va., said the transition from round helmets to elliptical or oval-shaped ones in the 1990s was “certainly not an improvement” safety-wise. But people wanted to look like Lance Armstrong.
A round helmet with a smooth surface is preferable, Swart said, because if a helmet snags during an accident, a rider’s head will be whipped around, possibly causing a concussion.
According to Roy Burek, a visiting professor at the Concussion and Traumatic Brain Injury Prevention Group at Cardiff University in Wales, cyclists can face four basic types of brain injury: skull fractures, interior brain bruising and swelling, brain bleeding and twisting or distortion of the brain.
Skull fractures and brain bruising result from direct impact and linear energy — the sort you would experience if you fell and hit your head on a curb. Bike helmets protect from these injuries quite well.
When a rider goes flying and skids to a stop, the brain experiences the effects of rotational energy, which can produce internal bleeding and contortion. “The brain is a little bit like an orange in a glass of water,” Burek said.
“If you twist the glass quickly, the orange won’t follow immediately behind.”
Helmet design could go in many directions. Swart envisions a smooth, round helmet with a softer material that survives more-dramatic impacts but wouldn’t need to be impractically thick.
Burek noted that most bicycle accidents occur at low speeds, so an ideal material for a helmet would be soft when you land at low speeds, to allow the brain to move and thus decrease damage from rotational energy. But that material would also be “smart” — firming up when a high-speed crash occurred, thus preventing a skull fracture.
Kurt thinks the most promising smart ingredient is, actually, air.
Kurt worked with scientists at Stanford University this year to test inflatable helmets. Something similar — collars that inflate like airbags when they sense a crash occurring — are available from Swedish company Hovding, but they don’t meet U.S. safety standards.
And for good reason, argues Swart: While Kurt’s research showed that these devices can withstand the same impact as helmets, they had to be overinflated to do so; they did not automatically inflate enough to protect against serious impacts.
Kurt worries that standards aimed particularly at preventing skull fractures may impede innovation of helmets that might be better at preventing concussions.
For example, helmets are required by the U.S. Consumer Product Safety Commission to withstand water (think rain) and extreme heat, which he said rules out anything with sensors that might be needed for a softer helmet.
Burek hopes for technologies that more closely mimic the scalp. If you press your fingertips against your head and move them around, you can feel that your scalp wiggles around relative to your skull. This wiggle room is important: It helps protect our brains from rotational energy in minor impacts by allowing our heads to move a bit in those cases.
Helmets are not designed to move when you crash, because you really don’t want them falling off.
“We need to come up with materials that don’t collapse head on, but twist and move in different directions like a second scalp,” Burek said. It’s a bit like landing on a water bed instead of a firm mattress.
Increased awareness about the long-term consequences of brain injuries for professional football players has led to an uptick in traumatic brain injury research and the development of new materials, Kurt said in an email.
Bicycle helmets pose a unique challenge, though, because the impact speeds of an accident, especially if a car is involved, can be much greater than that of colliding athletes.
But research on football helmets does help us better understand concussions, and given the attention being paid to preventing such injuries, Kurt said he is “fairly optimistic” we could see a better bicycle helmet in the not-too-distant future.