Continuing on our track of bike safety I have found and read some very interesting articles on helmets in the past 3 months. One from Bicycling Magazine from back in August and another short piece that just popped up from Outside Magazine. I think if you are a cyclist these articles are well worth the read. I will try and summarize both below. The Bicycling Magazine article points out some of the major flaws in current helmet designs in regards to safety and concussions. It is a lengthy read but well worth your time. The articles from outside is brief and takes a look at some of the new technologies going into helmets. Many of these technologies are coming from snow sports world and as winter looms the article focuses on winter sports helmets but many designs and features are shared.
Senseless - From Bicycle Magazine
The article begins by pointing out something you may or may not know. All cycling helmets (regardless of cost) pass the same safety test. The $200 helmet on the shelf isn't considered any safer than the $40 version, you pay extra for ventilation, fit, and feel, but not safety. This is actually a wonderful thing, it brings a safety device that can save lives to the masses. The helmet is great at preventing skull fractures and preventing other nicks and bruises from minor falls or low hanging branches. What the helmet doesn't do well is protect you from concussions. Concussions are one of the hottest topics in sports and it's a good thing to consider and address as quickly as we can. The more we learn about them the more dangerous they seem to become. The interesting thing with concussions is that they can occur in seemingly small crashes at low speeds. That isn't what the helmet is great at protecting us from, it is designed for big crashes and keeping our heads in once piece. Helmets are currently designed to spread impact out over space and time, lessening the impact. The big issue is that the current material used EPS doesn't begin to disintegrate and spread out the impact unless the force is very large. There in lies the big trade off, how do we get something that protects us for small slow impact falls but will still disintegrate correctly for major impacts. Next the article looks at standards for safety and the tests used to meet them.
"A lot of the innovation in helmets has been focused on making them lighter, more ventilated, and fit better," said John Thompson, bike helmet product manager for Scott Sports. "The customers leave it to the certifying authority to assure safety."
The certifying authority. That would be the Consumer Product Safety Commission. The federal agency sets out minimum standards to protect consumers against shoddy helmets.
But those testing standards aren't handed down by God on stone tablets. They come from somewhere.
I'm not going to go into detail about what the author found but it is safe to say there needs to be work done on these standards. If you only read one part I think this is possibly the scariest and most interesting. They are old and outdated considering the wealth of new information we have gained on head injuries. The tests aren't designed to test for concussion safety at all. When looking at a crash impact two forces act on your head. First you have linear acceleration (think head to pavement), second you have rotational acceleration. Rotational acceleartion is essentially your brain spinning within your skull, the problem there is that your brain isn't exactly a solid piece, it is made up of gray matter of closely packed neurons, think jello or tofu. Now try and spin jello and see what happens. The spinning will cause fissures in the jello and it will begin to break apart. The same thing occurs in your brain (give or take, that is a little scant on technical details) causing concussions and brain insures. Two main ways have been looked at to protect against this rotational acceleration.
- Spin Control - These systems incorporate an inner and outer shell, when a crash occurs the outer layer rotates away from the impact reducing probability of a concussion.
- Easing the Blow - Inner shell with many individual cells that compress against one another (think accordion) to reduce impact.
Building a Better Helmet - Outside Magazine
This article is very brief and worth a quick read after Senseless from above. It looks at 5 new materials being used in helmets to increase safety.
- Aerocore - Polymer form called Koroyd that replaces foam (30% reduction in force from EPS)
- Vinyl Nitrate - Soft Foam with a flexible shell (Good for high and low velocity impacts)
- MIPS - Multidirectional Impact Protection System - Addresses rotational forces with shells that move independently
- HIP-Tec - Multiple layers: rigid shell, EVA foam, and EPS
- Conehead - cone-shaped pockets of EPS foam that crush on impact that disperses energy laterally instead of vertically