Understanding Rotational Forces & How WaveCel Works

To understand WaveCel’s technology, benefits, and claims, it’s important to understand rotational forces, and why they are so harmful to human brains.

Rotational motion injuries are caused when the brain continues to move after the skull has come to a sudden stop (in the case of bike crashes, often because the head made impact with the ground at any angle other than a direct 90 degrees).

Research has long shown that severe brain injuries like Subdural Hematomas and diffuse axonal injury are linked to rotational motion, and mild traumatic brain injury, also known as concussion, is also believed to be caused by rotational motion.

In an accident, it’s no surprise that heads are far more likely to make impact with the ground (or a tree… or a wall… or a rock) at angles other than 90 than they are to make direct impact on a perfect 90 angle.

With this in mind, it’s easy to see why addressing rotational force is so important in helping to prevent both severe and mild brain injury.

How is WaveCel Tested, & Why?

There have been claims online that not testing WaveCel on real human brain impacts before launching means that our product is not fully vetted for safety.

However, it is important to understand how safe and ethical health studies are conducted in the real world.

It’s probably obvious why scientists don’t smash real, living people’s skulls into concrete to test impact forces, but to clarify: We don’t purposefully smash real, living people’s skulls into concrete to test our product because ethical science means never causing harm — to anyone.

We do, however, create robust testing systems using measurement devices attached to synthetic brains so that we can fully understand the impact forces that will transfer through a helmet during a crash.

Yep, sometimes that means starting with watermelons, gelatin, or egg yolks as visual aids for readers, but much of our research was completed with the most widely used human impact testing surrogate, the Hybrid III 50th percentile male anthropomorphic test device (ATD), which has been historically used in automotive and military testing, but has also been used to test athletic equipment and safety in recent years.

Almost all helmets on the market today include a standard expanded polystyrene foam (EPS) liner to mitigate direct impact, and this is highly effective at reducing the risk of skull fractures.

But to further improve protection and safety in real-world crashes, some helmets also include an additional lining to protect wearers from rotational motion and injury.

There are two types of helmet technologies that are designed to help mitigate rotational forces — the first, developed in 1996, is a slip liner that allows the head to continue to slide after the helmet has made impact. The second is WaveCel, a collapsible cellular lining that also allows for gliding, but additionally has the ability to flex at any angle and then collapse to help reduce impact forces even further.


We tested WaveCel at the Helmet Impact Testing (HIT) facility of the Portland Biomechanics Laboratory by dropping 3 types of bicycle helmets onto angled anvils at 30, 45, and 60 degrees at high speeds and measuring the headform rotational acceleration on the anthropomorphic test device that stood in for real human brains.

All 3 types of helmets (EPS-only “control” helmets, MIPS-lined “slip” helmets, and WaveCel helmets) are highly effective at reducing the risk of skull fracture, penetrating injury, and brain injury from direct forces.

In our testing, rotational acceleration was highest at 6.2 m/s impacts onto the 45° anvil.

In this impact scenario, SLIP helmets reduced rotational acceleration by 22% and WaveCel helmets reduced the same forces by 73% over control helmets.

Unsurprisingly, the control helmets had the highest AIS 2 brain injury risk of 59 ± 8% in this scenario.

At the same speed and angle, slip helmets and WaveCel helmets reduced the AIS 2 brain injury risk to 34.2% and 1.2%, respectively, compared to control helmets.

Armed with the knowledge of years of testing, we stand by our claims that WaveCel linings help to reduce rotational forces over standard foam helmet linings. Period.

Does that mean you will never experience a concussion if you wear a WaveCel helmet? Not necessarily. We can’t predict the future, nor can any gear arm you for every possible crash.

In fact, in a best-case scenario, you’ll never need your WaveCel helmet. We want you safe, and that means preventing crashes as well as protecting your brain if you do crash.

Read the full study results and methodologies mentioned above for free on the Pub Med website.

Ready to chase safest with us? Grab your WaveCel helmet today, whether you’re cycling, skiing, or snowboarding (with more to come soon).