There’s really no doubt about it – studies have shown time and time again that helmets improve your odds of surviving a crash. But by no means are they perfect, and just because they help, it doesn’t mean they can’t be better.
In an impact, there is any number of possible forces that may be inflicted upon your head, but for simplicity, crashes can be largely grouped into two categories, linear and oblique (1). A linear impact occurs when the applied force impacts the helmet at a 90-degree angle to the helmet. This is the simplest form of a crash, and the one tested for in standard safety testing (BS6658). You don’t have to be riding for long to realise that very few impacts that occur on a bike will only involve a force that is directly applied to the surface of your helmet, in fact, you’d be hard-pressed to come up with a plausible crash that involves only a right angle vector. Almost all impacts involve rotational forces (1) and it’s these rotational forces that really cause traumatic brain injuries (2). This is due to the way forces are dissipated, as a larger proportion of kinetic energy is transferred through the helmet and into the skull during a rotational impact (3).
POC knows this, so they hired a team of neuroscientists and doctors to see what they could do about it. POC’s latest technology, Shearing Pad INside (SPIN) is designed to make the helmet absorb as much of the energy of an impact as possible, instead of your head absorbing that trauma.
Elegant in its simplicity, the POC SPIN helmets have redesigned pads on the inside of the helmets which shear in the event of a rotational impact, absorbing the energy that would otherwise be applied to your head. This means the helmets look and fit exactly the same, except now they just provide you with more protection in a crash.
In an impact with rotation, as the energy passes through the helmet, there are three main points at which it will be dissipated:
- (A) The friction between the impacting surface and the outer shell of the helmet;
- (B) the internal energy in the liner and comfort foam due to shear deformation; and
- (C) frictional energy between the liner and the head (3).
Point C is the most undesirable, and the most likely to lead to a traumatic brain injury, so POC’s SPIN technology increases the amount of energy that is absorbed at point B, meaning that there is less energy remaining at point C and therefore minimising the force of the impact.
Unfortunately, despite the pads being the major upgrade in the SPIN system, they are unable to be retrofitted to old POC helmets.
POC SPIN technology helmets will be available from Pushys.com.au
(1) McIntosh, A. S., Lai, A., & Schilter, E. (2013). Bicycle helmets: head impact dynamics in helmeted and unhelmeted oblique impact tests. Traffic injury prevention, 14(5), 501-508.
(2) Kleiven, S. (2013). Why most traumatic brain injuries are not caused by linear acceleration but skull fractures are. Frontiers in bioengineering and biotechnology, 1, 15.
(3) Aare, M., Kleiven, S., & Halldin, P. (2004). Injury tolerances for oblique impact helmet testing. International journal of crashworthiness, 9(1), 15-23.
Categories: Product Review