Traditional bike helmets are intended to prevent skull fractures, but that’s not the only way your brain can be injured in an accident. Alongside any direct hit to the head, you could also experience a strong rotational force that can shake the brain inside your head. This rotational force can cause concussions and other brain injuries.
Concussions are being called a “silent epidemic” because they are relatively common and because their seriousness may not be immediately apparent. Moreover, repeated concussions have been found to cause a very serious brain injury called chronic traumatic encephalopathy (CTE).
Some newer bike helmets are designed to help manage the rotational forces to prevent concussions. Consumer Reports recently looked into these technologies to see if one was more effective than the other.
Typical head injury scenarios for bikers
When we imagine a bike accident, we often picture the biker being knocked to the ground — often head first. We picture any head injury being the result of a direct, or “linear” hit. That kind of hit certainly can and does cause serious brain injuries, including skull fractures.
Much more commonly, however, the biker’s head strikes the ground at an angle. This generates rotational forces, which carry through to the inside of the skull and shake the brain. The head takes a double-shock: the direct hit and the rotational trauma.
“Rotational motion is what correlates to how much the brain moves inside the skull,” a biomedical engineering and mechanics professor and director of Virginia Tech’s Helmet Lab told Consumer Reports. “If you can reduce the rotation of the head during impact, that reduces the strain or stretching of the brain, and that reduces the likelihood of injury.”
Helmets that reduce rotational force
Two relatively new technologies meant to reduce rotational forces upon impact are WaveCel and the MIPS Brain Protection System. WaveCel is quite new, while MIPS has been around since 2010 and is available in thousands of helmets.
According to Consumer Reports, MIPS helmets have an internal layer of stretchy fabric, plastic and other components. When the helmet is struck, this layer absorbs some of the rotational force. The helmet slides between about 10 and 15 millimeters before the internal layer is even pulled.
WaveCel helmets also redirect the energy of the collision, but in a different way. While MIPS helmets absorb the shock by sliding around on the head slightly, WaveCel helmets have an internal layer of malleable plastic in the form of three-dimensional mesh. This mesh crumples, flexes and glides sideways upon impact, much like a suspension system.
Is one technology better than the other?
WaveCel-affiliated researchers found that WaveCel helmets performed substantially better than both standard helmets and systems like MIPS at reducing rotational forces in collisions. MIPS-affiliated researchers were unable to confirm those results.
A Consumer Reports-sponsored test found that MIPS helmets outperformed standard helmets at reducing rotational force. (Consumer Reports’ testing of WaveCel helmets is ongoing.) Virginia Tech’s Helmet Lab found that the two systems offered comparable protection from rotational forces.
You may need to replace your current helmet
You should retire your old bike helmet if you ever crash and hit your head, whenever it shows signs of damage or wear, or once every five years.
When choosing your new bike helmet, you should definitely consider buying one with either MIPS or WaveCel technology. They do seem to reduce rotational force and the only downside seems to be cost.
Another important factor in choosing a helmet include fit and comfort. After all, a bike helmet can’t protect you at all if you don’t wear it.