cycling links



James Annan wrote:
>
> slim wrote:
>
> >
> > Tony Raven wrote:
> >
> >>Joe Keenan wrote:
> >>
> >>>One simple personal example of why I believe in wearing a helmet.
> >>>
> >>>Short story long:
> >>>
> >>>Daughter standing still stradling bike. Not cycling.
> >>>Age 12.
> >>>Wearing Helmet.
> >>>Gets foot tangled.
> >>>Falls sideways.
> >>>Force of hitting shoulder on ground forcibly snaps head to right with
> >>>a large deadening sound of THWACK as helmet strikes pavement.
> >>>Daughter unconscious.
> >>>Ambulance to hospital.
> >>>Diagnosis: Mild Concussion
> >>>
> >>
> >>Does your daughter trip over occassionally when not on the bike? Does
> >>she hit her head on the ground when she does? Do you make her wear a
> >>helmet all the time in case she trips over? Do you think having that
> >>extra half kilo weight strapped to her head had anything to do with why
> >>her head was forcibly snapped to the right? Yet even in exactly the
> >>sort of accident it was designed to protect against the helmet failed to
> >>prevent her being knocked unconcious!

> >
> >
> > A child does not fall with a horizontal speed 22 mph.

>
> Certainly not if she is standing still, as in the above anecdote. Did
> you have a point?


WHOOOOOOOOOOOOSH!

It went right over your head......at 22 mph. :)

--

http://www.bushflash.com/thanks.html
"Bubba got a BJ, BU$H screwed us all!" - Slim
http://www.worldmessenger.20m.com/weapons.html#wms
George "The AWOL President" Bush: http://www.awolbush.com/
WHY IRAQ?: http://www.angelfire.com/creep/gwbush/remindus.html
http://www.toostupidtobepresident.com/shockwave/chickenhawks.htm
 
Roberta Hatch wrote:
>
>
> Which, on the surface, would indicate a 30-precent reduction
> in head injuries. Is that what their revisied paper concludes?
>


The authors, while admitting the error have declined to say how it
affects their conclusions. There are two conclusions though one can
reach. Either polystyrene hats are indeed so magical that they even
protect people who are not wearing them or their is a major unidentified
confounding factor in their data which means no sensible conclusions can
be drawn from their it. I prefer the latter logical conclusion although
the authors seem to prefer the magic theory.

FWIW the "knee injury" paper is the Thompson Rivara Thompson one you
quoted. Its not written in the paper and you have to do the check that
any half competent analyst would do in a case control study. You chose
a variable that should not be affected and check that it does not come
out differently between the two groups. In this case, instead of taking
the authors data on head injuries you take their data on leg injuries
and apply their analysis methodology to it. If the two groups were
indeed comparable you would expect the same rate of leg injury between
the helmeted and non-helmeted group. The fact that the helmeted group
had significantly fewer leg injuries should immediately have set alarm
bells ringing with the authors that the two groups were not comparable
and that any other deductions were therefor suspect. Unfortunately they
did not do that simple check but its easy enough to do it for yourself.

Tony
 
Chris Phillipo wrote:
>
> Some cheap and effective protection for everyone would be to make it
> clear no one has the constitutional right to use public roads, it is a
> privilege that can be taken away at any time for not following the
> rules.


That may be so where you live, but where I live (and this is massively
cross posted internationally) we do have a right to use the public roads
on a bicycle, horse or foot although it is not a constitutional right as
we do not have a constitution (yet!)

Tony
 
Roberta Hatch wrote:
>
> Since you seem to be making a claim that helmets do not provide
> protection, how about you providing a reference to a whole-population
> study published in a scientific peer-reviewed journal, that shows that
> bicycle helmets do not prevent serious head and brain injuries.
>


Have you not read the Curnow reference I gave you, complete with on-line
link, yet?

Tony
 
Roberta Hatch wrote:
>
> I'm not missing any point, because there doesn't seem to be
> any paper making the claim you reported. Provide a pointer that
> "well known paper" and I'll make a comment.
>


Comment on Curnow then.

Tony
 
slim wrote:
>
>
> I didn't ask for a book report. ;-)
>
> I asked "Just how are YOU doing this?"
>


By following the advice in the book of course. There is a US
equivalent, Effective Cycling by John Forester.

Tony
 
Peter Clinch <[email protected]> wrote in message news:<[email protected]>...
> Jim wrote:
>
> > Many opinions carried to their logical conclusions will seem absurb.
> > That doesn't keep the opinion from presenting some merit on its way to
> > a logical and absurb conclusion. I do not know that walking down
> > stairs is more or less dangerous than cycling. I do not know with
> > certainty that the wearng of a helmet will lessen injuries and then
> > cost to society. It seems to me to be a behavior that one would
> > consider as cautious.

>
> Quite possibly, but on the other hand risk homeostasis tends to
> undermine such behaviour. For example, people buy "safer" cars with ABS
> brakes, but then drive faster (yes, they really do) and brake later, so
> the benefit is removed.
> In the wake of compulsory seat belts for drivers in the UK the main
> difference to casualties was an /increase/ in cyclist and pedestrian
> casualties from the worse driving caused by being "safer".
>
> Bottom line is that cyclist safety isn't fundamentally broken so doesn't
> need fixing. In the same way that coming downstairs isn't fundamentally
> broken and doesn't need fixing, even though there is some room for a
> little improvement which would save some lives.
>
> Pete.


There seems to be many assertions being made on what is probably
anecdotal observations. I do agree that it is foolish to negate the
benefits of a safety device, such as ABS. Risk homeostasis is an
interesting concept. I'll have to spend more time thinking about it.
I don't know if it really exists.
You are right that cyclist safety isn't fundamentally broken. This
doesn't mean that one shoul disregard cautious behavior.
As a general rule, I would not vote for legislation requiring bicycle
helmets. On the other hand, I would like not to be financially
responsible for what I consider foolish behavior.
I assume that it comes down to a personality difference. Given what
appears to me to be the same data, I am clearly more cautious in all
areas of my behavior than some of my associates, some of my children
and even my spouse.
 
Jim wrote:
> On the other hand, I would like not to be financially
> responsible for what I consider foolish behavior.
>


Does that mean if driving you would instinctively take more care near an
unhelmeted cyclist than a helmeted one? It certainly seems to be my
observation of drivers since I stopped wearing a helmet.

Tony
 
Jim wrote:

> There seems to be many assertions being made on what is probably
> anecdotal observations. I do agree that it is foolish to negate the
> benefits of a safety device, such as ABS. Risk homeostasis is an
> interesting concept. I'll have to spend more time thinking about it.
> I don't know if it really exists.


This is an excellent book, and the whole thing is on line (click the
table of contents and go on from there). It's not specific to cycling,
more about road safety in general, and it covers a lot more than risk
homeostasis

http://psyc.queensu.ca/target/

--
Joe * If I cannot be free I'll be cheap
 
Tony Raven <[email protected]> wrote:
>Roberta Hatch wrote:


>> Common sense prejudices?! I suggest you take your own advice.
>> _Evaluation and Replication of Impact Damage to Bicycle Helmets_, TA
>> Smith, D Tees, DR Thom, HH Hurt. _A case-control study of the
>> effectivness of bicycle safety helmets_, RS Thompson, FF Rivara, and
>> DC Thompson. Then move on over the the Snell Memorial Foundation and
>> the CPSC and have a look-see on what they have to say.


>Yawn. Not the infamous Thompson, Rivara and Thompson old chestnut.
>It has just about every error in the book from comparing
>non-comparable groups


In short, you don't like it, so it must not be legit. <yawn>

>> Wrong. A helemt will help prevent serious injury to the head
>> whenever it comes between a head and an object that it shouldn't. It
>> you want to dispute than, please do provide a scientific study to back
>> up your claim.


>Try "The efficacy of bicycle helmets against brain injury." Curnow WJ.
>Accident Analysis & Prevention, 2003;5 Feb 2003 for starters.
>(http://agbu.une.edu.au/~drobinso/AAP2002curnow.pdf)


Well thanks for the pointer. Let's a look-see at a brief
synopsis of that paper, shall we.

"An paper by Bill Curnow challenges the interpretation of scientific
evidence about the causes of serious injury to the brain. Drawing
upon extensive medical evidence,the author suggests that angular
(rotational) acceleration is the main cause of brain injury, especially
as a result of road crashes. Diffuse axonal injury (DAI) a consequence
of angular rotation is the cause of the most serious injuries and
long-term disability."

Nice try, but no cigar. The paper *disputes* a finding of
another paper. And, that paper in no way nullifies what I wrote.

>> Your graphs do not prove anything about helmet safety. I sugesst
>> you read and learn from those research papers I gave you earlier.


>You mean you cannot see a single discernable effect on head injury rates
>as a result of doubling helmet wearing rates?


I ment exactly what I wrote.

>Doesn't that tell you
>anything? As for learning from your research papers, those have been
>disected and critiqued a long time ago. Which is why some of us view
>anyone who starts by quoting TRT as not having done even the basic
>research and analysis.


Laugh. I suggest you not try to find fault with a single
paper, then ignore everything else put in front of your face. That's
exactly what you're doing in an attempt to 'prove' your claims.

Bobbi

---
Roberta Hatch '65 Panhead
Dykes on Bikes, San Francisco, CA (This space for rent)
 
slim pickin'[email protected] opined the following...
> You can say that with absolute metaphysical certainty?

^^^^^^^^^^^^^^^^^^^^^^^

What the hell is metaphysical certainty? Some kind of abstract
certainty?

> How arrogant!


It is however, an arrogance shared by the manufacturers of the helmets,
who put a disclaimer on their helmets about their efficacy in the event
of an accident involving motor vehicles.

How arrogant indeed!

Jon
 
Chris Phillipo [email protected] opined the following...
> I'm assuming you have seen some statistic I haven't? There's a reason
> firemen say "We never have to unbuckle a dead man."


Yes. It's because he's dead, and thus not a concern.

Jon
 
On Mon, 29 Nov 2004 18:36:08 GMT, slim <pickin'[email protected]> wrote in
message <[email protected]>:

>I asked "Just how are YOU doing this?"


Since it takes John Franklin nearly 200 pages this might be a long
reply :)

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University
 
"Jon Senior" <jon_AT_restlesslemon_DOTco_DOT_uk> wrote in message
news:[email protected]...
> Chris Phillipo [email protected] opined the following...
>> I'm assuming you have seen some statistic I haven't? There's a reason
>> firemen say "We never have to unbuckle a dead man."

>
> Yes. It's because he's dead, and thus not a concern.
>

Not sure where you are from but here in the real world rescuers don't make
it a practice of leaving corpses in wrecked automobiles. Interesting burial
practice you have though.
 
On Mon, 29 Nov 2004 14:40:39 +0000 (UTC), [email protected] (Roberta
Hatch) wrote in message <[email protected]>:

>Slipping on a "pile" of vomit has absoultly nothing
>to do with bicycle safety.


Interestingly, neither do helmets, according to whole population
figures from around the world. Puzzling, isn't it? It's almost as if
some of those studies have overstate the benefits somewhat, and the
helmet lobby have further distorted things. Who'd have thought it.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University
 
Chris Phillipo wrote:


> I guarantee you that in an impact at any speed a car with a seatbelt and
> airbag is better than any helmet currently available.



I guarantee you (if the helmet advocates are correct) that in an impact
at any speed a car with a seatbelt, airbag and helmeted occupants is
better than a car with seatbelt and airbag.

So why won't you wear a helmet while driving? I guess you don't think
your head is worth much...

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/
 
Chris Phillipo wrote:


> do you think all cyclists should be required to wear
> a hard shell full face helmet in order to get the full benifit? That I
> would have a problem with.


Why? If it saves one life...think of the children...isn't your head
worth it?

James
--
If I have seen further than others, it is
by treading on the toes of giants.
http://www.ne.jp/asahi/julesandjames/home/
 
On Mon, 29 Nov 2004 04:42:38 GMT someone who may be slim
<pickin'[email protected]> wrote this:-

>> > Daughter standing still stradling bike. Not cycling. [snip]
>> > Falls sideways. [snip]

>>

>A child does not fall with a horizontal speed 22 mph.


Correct.

That includes when they fall sideways off a stationary bike.


--
David Hansen, Edinburgh | PGP email preferred-key number F566DA0E
I will always explain revoked keys, unless the UK government
prevents me by using the RIP Act 2000.
 
On Mon, 29 Nov 2004 14:08:00 +0000 (UTC), [email protected] (Roberta
Hatch) wrote in message <[email protected]>:

>Since you seem to be making a claim that helmets do not provide
>protection, how about you providing a reference to a whole-population
>study published in a scientific peer-reviewed journal, that shows that
>bicycle helmets do not prevent serious head and brain injuries.


Changes in head injury with the New Zealand bicycle helmet law,
Robinson DL, Accident Analysis and Prevention 33 (2001) 687-691.

Head injuries and bicycle helmet laws, Robinson DL. 1996. Accident
Analysis & Prevention: 1996 Jul;28(4):463-75

Scuffham PA, Langley JD, 1997. Accident Analysis and Prevention: 1997
Jan;29(1):1-9 "Results revealed that the increased helmet wearing
percentages has had little association with serious head injuries to
cyclists as a percentage of all serious injuries to cyclists for all
three groups, with no apparent difference between bicycle only and all
cycle crashes"

There are other sources, although to be honest it is very hard to get
opinons published in the medical press which challenge the orthodox
view (not unique to this issue). Some of the leading data is
therefore published outside the medical press, e.g:

Reducing Bicycle Accidents: A Reevaluation of the Impacts of the CPSC
Bicycle Standard and Helmet Use, Rodgers GB. 1988. Journal of Products
Liability: 1988,11:307-317 - study of all 8,000,000 cyclist crashes in
the USA over a 15 year period; concludes: "... there is no evidence
that [helmets] have reduced the head injury and fatality rates. The
most surprising finding is that bicycle related fatality is positively
and significantly correlated with increased helmet use."

The problem with that, of course, is that it escapes inclusion in
meta-analyses, so the orthodoxy goes unchallenged and indeed appears
to grow without the need for new data (see Hormone replacement therapy
and coronary heart disease, Pettiti D, International Journal of
Epidemiology, 2004;33:461-463; The hormone replacement - coronary
heart disease conundrum: is this the death of observational
epidemiology? Lawlor DA, Smith GD & Ebrahim S, International Journal
of Epidemiology, 2004;33:464-467).

Have a look at this: http://www.cyclehelmets.org/papers/c2019.pdf

Look at the charts. That was what first inspired scepticism in me,
anyway.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University
 
Roberta Hatch wrote:

[snipped]

Can you explain how the helmet 'drop test' procedures used by Snell &
the like correlate to real-world cycling conditions?

We don't often fall on the top of our heads - in fact I'd suggest that
we never do.

So why are they testing for something that never happens?

Eric Schild
 

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