A helmet protects you. That's a given. But does it really protect against every type of impact?
This is the question a Swedish neurosurgeon asked himself more than thirty years ago. A line of thinking that profoundly transformed the design of modern helmets, whether bike helmets or ski helmets. Today, every helmet that complies with the CE EN 1078 standard delivers a level of protection that meets the safety requirements in force. MIPS® technology adds an extra layer of protection, designed to help reduce certain rotational forces that can occur during oblique impacts.
At first glance, all helmets seem to work the same way: an outer shell paired with a foam capable of absorbing the energy of an impact. Yet when you look at the real biomechanics of head trauma, an essential nuance emerges. Not all impacts are purely frontal. And not all trauma comes solely from a direct impact.
It is precisely from this observation that MIPS® technology was born.
An observation from the operating room
In the 1990s, Professor Hans von Holst, a neurosurgeon in Stockholm, treated many patients who had suffered head trauma following cycling or skiing accidents.
One detail came up again and again: some of them had in fact been wearing a helmet at the time of the accident.
So the problem was not simply the absence of protection. The question was more complex. Why could the brain still sustain serious injuries even when an approved helmet had absorbed the impact?
The answer lies in the way accidents actually happen.
Contrary to the simplified scenarios long used in laboratory testing, the head almost never strikes the ground perfectly vertically. During a fall on skis, it slides across the snow, rotating with the body before coming to an abrupt stop. On a bike, it usually arrives at an angle, slides across the asphalt or a rock, and rotates before the sudden stop.
This movement creates what researchers call rotational forces. In other words, the brain undergoes not only deceleration, but also a rapid rotational movement inside the skull.
Today, these rotational accelerations are considered one of the main mechanisms involved in concussions and certain diffuse traumatic injuries.
Traditional helmets already perform their role extremely well against direct linear impacts thanks to their absorbing EPS (Expanded Polystyrene) foam. However, they were long designed primarily to absorb vertical energy. Rotational movements were taken into account far less, whether for a ski helmet or a bike helmet.
Hans von Holst then decided to explore a new approach. The goal was no longer simply to absorb the impact, but also to reduce part of the rotational forces transmitted to the brain.
A technology inspired by the human brain
To develop this idea, Hans von Holst joined forces with engineers and researchers at the KTH Royal Institute of Technology in Stockholm.
Their starting point is fascinating: the brain already has its own natural protection system.
Contrary to what you might imagine, the brain is not rigidly fixed to the skull. It floats in a fluid called cerebrospinal fluid. This fluid allows it to move slightly during an impact and to dissipate part of the mechanical stress.
The principle behind MIPS® is directly inspired by this biological mechanism.
The goal is simple: to allow a controlled micro-movement inside the helmet in order to limit certain rotational forces before they are transmitted to the brain.
After several years of biomechanical research, development and testing, the MIPS® system, short for Multi-directional Impact Protection System, came into being.
How MIPS® technology really works
The effectiveness of a helmet during a bike crash is a fact that no longer needs proving. To go even further, Cairn and MIPS® jointly developed a helmet that is even safer for your head. Accident statistics show that, most often, falls and impacts produce an angular impact (less than 90°) to the head. These so-called "rotational" impacts can be the cause of severe brain injuries. The MIPS® system (Multi-directional Impact Protection System) is designed to absorb this rotational force in order to reduce its impact on the brain.
In a helmet equipped with MIPS®, a thin low-friction layer is placed between the protective EPS foam and the inner liner in contact with the head.
In everyday use, this technology remains practically imperceptible. It alters neither the helmet's overall comfort, nor its ventilation, nor its fit.
Its role appears only during an oblique impact.
During the first milliseconds of the impact, this layer allows a slight relative movement between the head and the helmet, generally of a few millimetres. This micro-slip helps redirect and dissipate part of the rotational energy before it is fully transmitted to the brain.
On a human scale, the phenomenon is extremely fast. A blink of the eye lasts about 100 milliseconds. The MIPS® system acts in just a few milliseconds.
This movement is invisible to the user, but it can change the way certain mechanical forces reach the brain during a fall.
Why this technology is especially relevant in outdoor sports
In reality, accidents are rarely clean, linear or predictable.
On a bike, falls often happen in a corner, after a loss of grip, during emergency braking or after lateral contact. In mountain biking, roots, rocks and shifts in balance frequently generate oblique impacts. On road or gravel, speed considerably increases the energy involved in a fall.
In winter sports, the issue is even more obvious. Snow and ice naturally encourage sliding and rotation of the body before the final impact. A skier who falls in a turn, a snowboarder who takes a carve too tight, or a freestyler who misses a landing: in all these cases, the head often slides across the surface before coming to an abrupt stop. It is precisely in these fractions of a second that MIPS® comes into play.
In all these scenarios, a classic helmet already absorbs a large part of the direct impact. MIPS® adds extra protection specifically designed for the rotational movements present in real-world accidents.
In concrete terms, MIPS® technology provides complementary protection in four typical situations:
• A bike fall in a corner with the head sliding sideways across the asphalt
• An MTB impact on uneven terrain after catching a root or a rock
• A ski or snowboard fall on hard or icy snow with the body rotating
• Any oblique impact at high speed, whatever the discipline
What the scientific studies show
Recent research in biomechanics confirms the importance of rotational accelerations in many head injuries.
Several studies have observed that helmets equipped with rotational systems such as MIPS® reduce certain measures linked to angular movements of the head during oblique impacts.
A study published in 2024 in the *Chinese Journal of Traumatology* notably showed a measurable decrease in rotational accelerations during tests comparing MIPS® helmets with conventional helmets in oblique impact scenarios.
These results obviously do not mean that a MIPS® helmet prevents all concussions. No helmet today can guarantee absolute protection against head trauma.
However, current scientific data suggest that, with an equivalent design, a rotational system delivers a real biomechanical benefit in certain types of accidents.
MIPS® does not replace the fundamentals
It's important to remember that no technology can make up for a poor helmet or a poorly adjusted one.
Overall design quality remains decisive. The absorption capacity of the EPS foam, head coverage, stability, hold and fit all play a fundamental role in real-world protection.
An excellent helmet without MIPS® will always protect better than a poorly designed helmet equipped with this technology.
MIPS® should therefore be seen for what it really is: an additional improvement that complements an already high-performing helmet.
Cairn helmets equipped with MIPS® technology
Cairn offers several models featuring MIPS® technology depending on the discipline.
In mountain biking, the Edge MIPS® and the Rift MIPS® are designed for technical terrain where oblique impacts are most frequent. The EDGE MIPS® targets demanding riders looking for the highest level of protection on the trail. The RIFT MIPS® is aimed at regular mountain bikers who don't want to compromise on safety. Both feature in-mold construction, meaning a polycarbonate (PC) shell heat-fused with the EPS foam, which ensures a package that is both lightweight and strong.
On road and gravel, the ATOM MIPS® brings the technology to a helmet designed for long rides at high speed, where the energy involved in a fall is greatest.
In skiing and snowboarding, Cairn also offers models equipped with MIPS® technology to meet the demands of winter sports. On hard or icy snow, oblique impacts are particularly frequent and rotational forces particularly high. A ski helmet like the RISE MIPS® or the XPLORER MIPS® provides complementary protection here that makes complete sense, whether you're a weekend skier or a seasoned rider tackling varied terrain.
Conclusion
Choosing a MIPS® helmet is not about looking for miracle protection. It's about adding an extra layer of safety designed around the real biomechanics of head trauma.
Perfectly vertical impacts exist mainly in laboratories. In real life, whether you're on a single track on your bike or on snowy slopes, accidents almost always involve oblique and rotational movements. MIPS® answers this reality with a solution that is discreet, scientifically proven and available on quality helmets.
And when it comes to protecting the brain, a few milliseconds can sometimes make a considerable difference.
Discover the Cairn helmets equipped with MIPS® technology and find the model suited to your discipline.
