matticus
Guru
Talking of different standpoints - which is often a good thing - what are your thoughts on Olympic Boxing removing helmets a few years ago?
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MontyVeda
a short-tempered ill-controlled small-minded troll
- Location
- Lancaster... the little city.
I'm guessing when it comes to Epilepsy, each individual is assessed separately; some 'need' to wear a helmet, some don't, some aren't allowed to drive whilst some can (I think?). Not sure its a worthy comparison to be honest.
classic33
Leg End Member
Don't watch boxing*, so can't offer an honest opinion.
*Unless you count the Rocky movies.
classic33
Leg End Member
It's the same part of the body they're protecting, the head. The effect on the head, upon impact, is the same. Your head comes to a sudden stop, but your brain remains "bouncing around" inside your skull, regardless of any exterior damage suffered. I doubt the body differentiates between any impact, by cause.
They are worn whilst walking, covering the often raised question of would you wear one whilst walking, not cycling.* However there's no talk about going "round with a bag of sugar on your head", which will add to any injury suffered. "It will feel odd/uncomfortable at first until you get used to it", with no mention of rotational injuries being caused by them.
From a standing fall(log fall), the head of person can be doing in excess of 30mph by the time it hits the ground.
*So far the choice on wearing for either is mine, and I'd prefer it to remain my choice. Not someone making that choice for me.
MontyVeda
a short-tempered ill-controlled small-minded troll
- Location
- Lancaster... the little city.
the design of epilepsy hats is very different to the standard cycling helmet though. They're not a rigid mushroom shape, and doing a quick google image search for 'epilepsy hats', some of them look like normal hats.
DaveReading
Don't suffer fools gladly (must try harder!)
- Location
- Reading, obvs
An object would have to fall from about 9 meters to attain 30 mph by the time it hits the ground, unless other external forces are involved.
matticus
Guru
Rotational injuries come about when falling off motorbikes/pushbikes at high speed and glancing off the road.
Studies show brain injuries from rotation, in impacts where there isn't enough linear g-force to damage the brain i.e. it's a new injury type brought on by headwear.
Re: log falls. I'm speculating here, but someone having a seizure would have less reflexive defence mechanisms such as throwing an arm out. So injury causes and types will be different to a (conscious) cyclist.
Studies show brain injuries from rotation, in impacts where there isn't enough linear g-force to damage the brain i.e. it's a new injury type brought on by headwear.
Re: log falls. I'm speculating here, but someone having a seizure would have less reflexive defence mechanisms such as throwing an arm out. So injury causes and types will be different to a (conscious) cyclist.
MontyVeda
a short-tempered ill-controlled small-minded troll
- Location
- Lancaster... the little city.
I always thought it was around 12mph* in the case of a log fall
*no idea why. I might have read it or imagined it... both are equally reliable in my book.
DaveReading
Don't suffer fools gladly (must try harder!)
- Location
- Reading, obvs
That sounds about right. 30 mph certainly isn't.
It's very definitely not. You can come up with a reasonable estimate by treating the human body as a pendulum with a known weight at the end (the head) and estimating the total potential energy and the consequent impact velocity in the vertical plane (ignoring any side to side motion as that wouldn't change the impact velocity).
Doing that with an approx 5kg head (slightly heavier, but a round number) for someone 2m tall (roughly my height, and also easier to calculate) gives an impact speed of between 12 and 13 mph.
Ming the Merciless
There is no mercy
- Location
- Inside my skull
Not sure where you get 30 mph from. If someone trips up then gravity with accelerate their head to around 12-13 mph by time it impacts the ground. That assumes their feet are no longer in touch with the ground. If the feet remain in contact and the person pivots then the impact speed will be less.
MontyVeda
a short-tempered ill-controlled small-minded troll
- Location
- Lancaster... the little city.
I think Dave was saying my 12mph estimate sounds about right... which your calculation agrees with.
Yep, that's the way I read it too.I think Dave was saying my 12mph estimate sounds about right... which your calculation agrees with.
Of course, one thing that is worth bearing in mind is that the shorter you are the lower your impact speed. Possibly the only benefit of being a short-arse
MontyVeda
a short-tempered ill-controlled small-minded troll
- Location
- Lancaster... the little city.
so if a standing (log) fall results in a head impact of around 12mph, and the standard 'cycling' helmet is tested to impacts of around 12mph, is it not more suited to being marketed as a pedestrian helmet? (perish the thought! who'd fall for that?!)
DaveReading
Don't suffer fools gladly (must try harder!)
- Location
- Reading, obvs
Depends.
You would have to look at stats (if they exist) on how often in a collision (a) the cyclist's head hits the object being collided with, or (b) the cyclist comes off and hits their head on the ground.
Bear in mind that even if you fall off your bike at 30 mph, the vertical component of your velocity when you hit the ground (which is the bit that matters) will still only be about 12 mph.
