On Tue, 22 Jan 2008 09:17:09 -0800, SMS <[email hidden]>
Quoted message said:Clive George said:"vey" <[email hidden]> wrote in message
news:[email hidden]...
Quoted message said:[email hidden] wrote:
>> So what's the straight [censored]? Does Snell matter?
>
> Dear Vey,
>
> Table at bottom shows differences between tests, text explains some
> details:
> http://www.cyclehelmets.org/papers/c2023.pdf
>
> Cheers,
>
> Carl Fogel
TMI. I think I read here that Snell matters, but in the UK, Snell
approved are not much available. Is that about right?
Sounds about right. Trouble is, the Snell standards are higher than the
others, so it's easier to make a light well ventilated helmet which
meets just the lower ones.
A big difference is self-certification versus third-party certification.
As far as I know, Snell doesn't allow self-certification, but CPSC and
ASTM do allow self-certification.
See "http://www.oninjuryresources.ca/downloads/cf128031450656958768.ppt"
IMVAIO, if a cyclist is going to wear a helmet they should at least get
the Snell certified helmet to be sure that the design has been tested by
an independent organization. I have a Snell certified Specialized helmet
that is no less ventilated and no heavier than a self-certified helmet,
so it's certainly possible to make a light, well-ventilated, Snell
approved helmet.
That said, all the studies of helmet effectiveness don't take into
account whether or not the helmet was self-certified or third party
certified. Given the huge body of evidence showing the benefits of
helmets in head impact crashes, it's not clear how much more protection
the Snell approved helmet gives verses self-certified helmet.
For a good review of the helmet effectiveness studies, see
"http://www.helmets.org/henderso.htm"
Dear Steven,
It's a very painstaking but very poor review, if not outright
nonsense.
No reader could guess from the passage below that the Thompson-Rivara
comparison of two groups of helmeted and unhelmeted riders concluded
that helmets reduced serious head injury and death by ~85% (they later
admitted that their arithmetic was wrong) without noticing that the
helmets also reduced leg injuries by 75%.
Either helmets magically protect legs, or else the two groups were not
comparable.
"Thompson et al (1989) conceded that they could not completely role
out the possibility that more cautious cyclists may have chosen to
wear helmets and also had less severe accidents. Spaite et al (1991)
compared injuries sustained by helmeted and unhelmeted riders in
collisions with motor vehicles, finding that the helmeted riders had
less injury to other parts of the body as well as to the head. They
concluded that the collisions for these riders had been less severe,
because the riders had been more cautious. However, Thompson et al
(1989) made adjustments made for age, experience, and accident
severity should have largely accounted for such potential differences
between case patients and controls."
Cheers,
Carl Fogel