The image of a dazed and confused hockey player carried off the ice on a stretcher may soon be a thing of the past.
Researchers from the University of Ottawa’s Neurotrauma Impact Laboratory have developed an ice hockey helmet testing system that measures the level of angular acceleration—or rotation—of the head during a concussion.
Blaine Hoshizaki, director of the lab and chair of the International Standard Committee, which deals primarily with certification standards of hockey helmets and facial protection, says historical research points to angular acceleration of the head as a predictor of concussion.
He’s optimistic that once helmets are designed to manage angular acceleration, the amount of concussions in hockey will decrease.
“Then there will probably be standards that require a certain level of angular acceleration management by the helmet,” said Hoshizaki.
In the next five years, he envisions the engineering of more complex and sophisticated energy absorbing structures by Nike and Reebok, the two biggest hockey equipment manufacturers.
“They both have very sophisticated development labs. I put them in so I should know,” said Hoshizaki. “That’s the nice thing […] once you develop these tools for [the manufacturers], they will put them into play very quickly.”
World renowned injury prevention specialist Pat Bishop has spent nearly 40 years serving on various Canadian Standards Association (CSA) technical committees. With projects that include the evaluation of head protection in hockey, Bishop thinks changing the system of padding in the helmets could be a useful suggestion.
Bishop says this may reduce the magnitude of the impact force, which in turn reduces the vector component of the rotational force.
“The question then becomes, what’s the padding?” said Bishop. “How thick does it have to be, how massive does it have to be? Those questions are trying to be addressed by some people.”
Ryan Ouckama, a PhD student at McGill University, is trying to improve the protection of hockey helmets by investigating their local pressure distribution. Ouckama launched hockey pucks on to the sides of helmets and measured the corresponding acceleration of the head form in the helmet.
What he found was that even relatively low accelerations had pressures capable of causing bone fracture in the skull.
“You sort of had contradicting measures: you had acceleration measures saying it was well below these current standards of what’s considered a dangerous impact, yet it was still obviously dangerous to possible [hockey players] that could be wearing it because of these relatively high pressures,” said Ouckama.
Elbows, punches, sticks, and shoulders to the head are just some of the instances that can lead to angular acceleration of the head in hockey.
Picture a hook punch to the jaw in boxing, which causes the head to rotate on two planes: coronal (head moving up or down) and sagittal (head moving left or right). When this happens, rotation of both the brain and brain tissues occurs, disrupting its nerve axons and causing concussion.
Currently, the predominant North American system for testing helmets measures only linear acceleration during impact.
This testing involves a guillotine-like apparatus in which a sculptured head wearing a helmet is guided from a defined height on to a flat rigid surface. When traveling down, the helmeted head form moves in a straight line, prevented from rotating.
Once it strikes the ground, it quickly decelerates from its impact velocity to zero. This deceleration is taken as the linear acceleration.
The numbers that come out of helmet testing through linear acceleration determine whether or not a helmet, under current standards, is safe.
“And by safe we mean that it’s not going to produce things like skull fractures and brain bleeds,” said Bishop.
He agrees with Hoshizaki that angular acceleration appears to be the culprit in causing concussions. Designing a helmet that reduces it may lead to fewer concussions.
But Bishop still remains skeptical.
“It’s a challenge. If it can be done effectively, it is a step in the right direction,” said Bishop. “I’m not sure myself if it can be done. But they said you couldn’t put a man on the moon either. Never say never.”
The big problem, according to Hoshizaki, is that the industry doesn’t usually invest in research that tries to improve on equipment safety standards.
“It’s up to us at the universities to undertake it and make sure these standards becomes safer and [in this case] result in safe helmets.”
