Stupid helmet question ...

"Mike Clark" wrote in message
.uk...
| In message
| "pg" wrote:
|
| [snip]
| When you ski 80, sometimes 100 days or more a year in all
conditions,
| all terrains, sometimes at sixty, seventy miles an hour or more on
| ice - you soon realise that the only things separating you from
| disaster are intelligent skiing, experience, fitness, technique,
with
| a sizeable dose of luck thrown in. The analogy between owning a
| helmet and having a more powerful and efficient car doesn't work -
| the race skiers concerned are already skiing at the limit. As for
| mountain born and bred 'fun' skiers - wearing a helmet would not
| significantly affect how safely they ski. The vast majority of
| regular local alpine skiers (ime) learn a form of respect for
others
| on the snow, for the mountain environment.
| [snip]
|
| I think the article you referenced on the snowsports website can give
| some insight to this question of experience and safety.
|
| If you look at Table 1 of the article
|
| http://mysnowsports.com/News/article/sid=591.html
|
| You can see a section that analyses the data by "skiing ability"
|
| This shows that 19.1% of the control group of skiers are "Expert" and
| 18.7% of the injured skiers are "Experts" with 18.4% of those with
| serious head injuries being "Expert". If being an expert skier made
you
| safer than average you would expect the injured percentages to be
| relatively lower than the controls. Similarly for "Good" skiers the
| results are 35.3% versus 32.2% versus 32.7%.
|
| Interestingly the biggest safety effect is seen amongst those who are
| only classed as "intermediates". They make up 33.6% of the controls
but
| only 25.4% of the injured, or 26.5% of the seriously injured. In other
| words those skiers who are classed as "intermediates" do in fact
appear
| to be at a relatively lower risk of injury than are "Experts".
|
| Beginners are at the highest risk making up 11.6% of controls but
21.3%
| of injured and 21.8% of seriously injured.
|
| So what this seems to show is that "beginners" start off with a higher
| than average risk but then progress to a stage as "intermediates" when
| they are much safer than average. However as they progress further to
| "Good" and then on to "Expert", the risks per skier increase again.
|
| Clearly if the only factor that was important was level of skill you
| might expect that as ability improved that injuries would always
| decrease. But of course what happens is that as ability improves the
| individials clearly do change their exposure to risk.
|
| The above data is consistent with risk compensation by the skiers and
| boarders who were studied.

I have a problem with skier levels that appear to be some kind of
nebulous self-classification arrived at by the skiers themselves. The
vast majority of those questioned will have been week or two a year
tourists as opposed to locals, or professional skiers. Very few of these
are expert, or even advanced, except in their own minds... Without
knowing how these labels were arrived at, I don't think we can draw any
conclusions.

The expert skiers I was referring to are the ones that are on an
entirely different level - not just in terms of skill, but in terms of
awareness, experience, attitude. The majority ski well within the
limits, according to the snow/weather/traffic conditions, except in
competition/race training. Donning a helmet would not change this one
iota.

I think we're talking in circles here. The issue is whether people
adjust their behaviour in accordance with a perceived change in risk. I
pointed out that with respect to the *real* (not Slush 'n Rubble)
experts, or with respect to knowledgeable mountain-dwelling locals, any
change in behaviour would in my view be negligeable or non-existent.

I suggested that with respect to a child who has never known anything
else, he would not be taking increased risks when compared to a
hypothetical identical child brought up to an identical skiing standard
without ever wearing a helmet.

Pete
http://mysnowsports.com

In message
"pg" wrote:


"Mike Clark" wrote in message
.uk...
[snip]
|
| I think the article you referenced on the snowsports website can give
| some insight to this question of experience and safety.
|
| If you look at Table 1 of the article
|
| http://mysnowsports.com/News/article/sid=591.html
|
| You can see a section that analyses the data by "skiing ability"
|
| This shows that 19.1% of the control group of skiers are "Expert" and
| 18.7% of the injured skiers are "Experts" with 18.4% of those with
| serious head injuries being "Expert". If being an expert skier made
you
| safer than average you would expect the injured percentages to be
| relatively lower than the controls. Similarly for "Good" skiers the
| results are 35.3% versus 32.2% versus 32.7%.
|
| Interestingly the biggest safety effect is seen amongst those who are
| only classed as "intermediates". They make up 33.6% of the controls
but
| only 25.4% of the injured, or 26.5% of the seriously injured. In other
| words those skiers who are classed as "intermediates" do in fact
appear
| to be at a relatively lower risk of injury than are "Experts".
|
| Beginners are at the highest risk making up 11.6% of controls but
21.3%
| of injured and 21.8% of seriously injured.
|
| So what this seems to show is that "beginners" start off with a higher
| than average risk but then progress to a stage as "intermediates" when
| they are much safer than average. However as they progress further to
| "Good" and then on to "Expert", the risks per skier increase again.
|
| Clearly if the only factor that was important was level of skill you
| might expect that as ability improved that injuries would always
| decrease. But of course what happens is that as ability improves the
| individials clearly do change their exposure to risk.
|
| The above data is consistent with risk compensation by the skiers and
| boarders who were studied.

I have a problem with skier levels that appear to be some kind of
nebulous self-classification arrived at by the skiers themselves. The
vast majority of those questioned will have been week or two a year
tourists as opposed to locals, or professional skiers. Very few of these
are expert, or even advanced, except in their own minds... Without
knowing how these labels were arrived at, I don't think we can draw any
conclusions.

I can accept that partially in that we can't define exactly the
objective level of classification, but it is still the fact that self
classification of ability defines groups who appear to show different
levels of risk. What it clearly shows is that those who regard
themselves as "Expert" are at more relative risk than those who regard
themselves as "Intermediate". How do you interpret the result if you
don't think it is possibly due to "risk compensation".


The expert skiers I was referring to are the ones that are on an
entirely different level - not just in terms of skill, but in terms of
awareness, experience, attitude.

And I've agreed in other postings that it is possible that there is such
a subgroup who behave slightly differently. But such "experts" are
likely to be a tiny fraction of the total so most likely won't have much
of an impact on general statistics at a population level.

The majority ski well within the limits, according to the
snow/weather/traffic conditions, except in competition/race training.
Donning a helmet would not change this one iota.

That is a possible hypothesis but is there data that addresses and
verifies it? Do these people generally wear helmets when not practicing
or racing?


I think we're talking in circles here. The issue is whether people
adjust their behaviour in accordance with a perceived change in risk.

Which at a population level there is plenty of evidence for.

I pointed out that with respect to the *real* (not Slush 'n Rubble)
experts, or with respect to knowledgeable mountain-dwelling locals,
any change in behaviour would in my view be negligeable or
non-existent.

But the question is are local knowledgeable, skilled people at much
lower risk of injury? You might need to calculate risk per day of skier
exposure to compensate for increased time of exposure.

There are clearly many more visitors than locals on the slopes, but are
the locals at much less risk per day of skiing than all the visiting
groups?


I suggested that with respect to a child who has never known anything
else, he would not be taking increased risks when compared to a
hypothetical identical child brought up to an identical skiing
standard without ever wearing a helmet.

Yes because they will have both reached a risk homeostasis that they
were comfortable with.

The point about this that you don't seem to be accepting is that the
introduction of measures to improve safety don't seem to always result
in expected improvement in safety when you look at the data.



Pete http://mysnowsports.com



The question is whether there is any statistical evidence to test this
out with respect to injuries in skiing? Do you know whether injuries
amongst racers have decreased or increased over time and as equipment
has changed?

From a quick search through the literature I've only found a few studies
but the one you have copied on the snowsport website certainly seems to
provide evidence consistent with "risk compensation" amongst skiers and
boarders.


Mike
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"

In message k
Mike Clark wrote:

[snip]
From a quick search through the literature I've only found a few studies
but the one you have copied on the snowsport website certainly seems to
provide evidence consistent with "risk compensation" amongst skiers and
boarders.


Two other bits of evidence in favour of "risk compensation" type
behaviour shown in

http://mysnowsports.com/News/article/sid=591.html

are

(1) of 700 interviewed specifically about risk taking behaviour, those
who classified themselves as risk takers were much more likely to wear a
helmet than those who did not (OR 1.48) and this ratio was consitent
across sex, equipment type, age groups, and skiing ability.

(2) Those who classified themselves as "Expert" were much more likely to
wear a helmet than those who only classified themselves as
"intermediate", yet the "Experts" were also at higher risk of
serious head injury than the "intermediates".

Mike
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"

On 18 Jan 2007 16:15:44 GMT, Switters wrote:

On Thu, 18 Jan 2007 14:26:05 GMT, Champ allegedly
wrote:

The exceptions are when, for whatever reason, I just know that I'm not
going to be going off piste at all, whatever.

What are these ficticious days of which you speak?

The only day I can maybe think of was the day after doing Mt Blanc.

Well, that was one of them.

Another was last Christmas at Tignes with Ace. There were a few days
when there really was absolutely zero off piste opportunities
whatsoever.
--
Champ

On Thu, 18 Jan 2007 17:57:41 +0100, "pg"
wrote:

Before getting into the meat of your reply, let me put this to you.

Race skiers N years ago did not wear helmets. Race skiers today do wear
helmets. If it were possible to compare a cross section of racers from
both eras, would there be a difference in the degree of risk taken by
each? I suggest none whatsoever.

I suggest you'd be very wrong.

I race motorcycles on the Isle of Man TT circuit [1]. For those that
don't know, this is on public roads, between dry stone walls, hedges,
trees, etc, compared to purpose built circuits like Brands Hatch,
Silverstone, etc, which have large run off spaces. If you crash at
Silverstone, you usually don't even get a bruise. If you crash on the
TT course, you've got a fairly high chance of dying.

It's an obvious and completely accepted fact amongst motorcycle racers
that they take less risks on the TT course than they would on a
purpose built circuit.

And anyway, it really doesn't matter how much you protest that this
phenomenon either isn't true, or doesn't apply to you, or certain
other sub-groups. It's a widely demonstrated phenomenon, across a
huge range of activities and populations, and has masses of scientific
literature to back it up. It's true. You believe what you want.


[1] at the amateur version, the Manx Grand Prix
--
Champ

On Thu, 18 Jan 2007 21:01:56 +0000, Champ wrote:

On Thu, 18 Jan 2007 17:57:41 +0100, "pg"
wrote:

Before getting into the meat of your reply, let me put this to you.

Race skiers N years ago did not wear helmets. Race skiers today do wear
helmets. If it were possible to compare a cross section of racers from
both eras, would there be a difference in the degree of risk taken by
each? I suggest none whatsoever.

I suggest you'd be very wrong.

I race motorcycles on the Isle of Man TT circuit [1].

coughpahndcough

--
-Pip

"Champ" wrote in message
...
| On Thu, 18 Jan 2007 17:57:41 +0100, "pg"
| wrote:
|
| Before getting into the meat of your reply, let me put this to you.
|
| Race skiers N years ago did not wear helmets. Race skiers today do
wear
| helmets. If it were possible to compare a cross section of racers
from
| both eras, would there be a difference in the degree of risk taken by
| each? I suggest none whatsoever.
|
| I suggest you'd be very wrong.
|
| I race motorcycles on the Isle of Man TT circuit [1]. For those that
| don't know, this is on public roads, between dry stone walls, hedges,
| trees, etc, compared to purpose built circuits like Brands Hatch,
| Silverstone, etc, which have large run off spaces. If you crash at
| Silverstone, you usually don't even get a bruise. If you crash on the
| TT course, you've got a fairly high chance of dying.
|
| It's an obvious and completely accepted fact amongst motorcycle racers
| that they take less risks on the TT course than they would on a
| purpose built circuit.
|
| And anyway, it really doesn't matter how much you protest that this
| phenomenon either isn't true, or doesn't apply to you, or certain
| other sub-groups. It's a widely demonstrated phenomenon, across a
| huge range of activities and populations, and has masses of scientific
| literature to back it up. It's true. You believe what you want.

I've no problem with that, as I've only addressed the issue with respect
to one particular group that I happen to know rather well - the ski
racing community. It's a straw man to suggest that I have argued from
the particular to the general.

As for your motorcycle analogy, a ski helmet offers little or no
protection above a certain velocity, and with speeds of up to 85,
sometimes 90 mph on a downhill, it's pretty irrelevant to whether you
survive more than a glancing blow at those speeds.

The equipment (other than helmets) and the piste preparation were not
the same in the era to which I was referring, but the winner in the
speed disciplines has always been the one who combined optimum technique
with maximum fearlessness.

Beyond the small section of the skiing population I mentioned, there are
without a doubt plenty of people who will to a degree be wrongly and
excessively reassured by a helmet. The interesting question is whether
the negative effect of this outweighs the potential benefits. If so,
there's nothing to stop better education/information about the risks and
actual level of protection provided.

In the (only) group I have been discussing (ski racers / mountain
dwellers), I reckon the effect - if any - would be negligible.

Pete
http://mysnowsports.com

"Mike Clark" wrote in message
.uk...
| In message
| "pg" wrote:
|
|
| "Mike Clark" wrote in message
| .uk...
| [snip]
| |
| | I think the article you referenced on the snowsports website can
give
| | some insight to this question of experience and safety.
| |
| | If you look at Table 1 of the article
| |
| | http://mysnowsports.com/News/article/sid=591.html
| |

snip

| I can accept that partially in that we can't define exactly the
| objective level of classification, but it is still the fact that self
| classification of ability defines groups who appear to show different
| levels of risk. What it clearly shows is that those who regard
| themselves as "Expert" are at more relative risk than those who regard
| themselves as "Intermediate". How do you interpret the result if you
| don't think it is possibly due to "risk compensation".

Those who overestimate their abilities are more prone to accident,
that's self evident. But the question is how much of a factor the
wearing of helmets by experts would lead to a change in perception of
risk. All I can glean from these results is that people who think they
are good are more likely to fall over with or without helmets, and
certainly not that people who -are- skilled skiers are taking extra
risks as a result of wearing helmets.

|
| The expert skiers I was referring to are the ones that are on an
| entirely different level - not just in terms of skill, but in terms
of
| awareness, experience, attitude.
|
| And I've agreed in other postings that it is possible that there is
such
| a subgroup who behave slightly differently. But such "experts" are
| likely to be a tiny fraction of the total so most likely won't have
much
| of an impact on general statistics at a population level.

True, but I have only ever introduced a point with respect to mountain
dwellers and 'professionally' trained skiers to show that the 'risk
compensation' factor doesn't - imv - apply across the board. Clearly
without adequate education and training with respect to the risks
involved, with or without a helmet, occasional skiers may be vulnerable
to a small degree of increased confidence when they first wear a
helmet - but possibly only for a limited period.

| The majority ski well within the limits, according to the
| snow/weather/traffic conditions, except in competition/race
training.
| Donning a helmet would not change this one iota.
|
| That is a possible hypothesis but is there data that addresses and
| verifies it? Do these people generally wear helmets when not
practicing
| or racing?

With respect to youngsters, the great majority. All of those in race
clubs. Older generations living out here? Less so, but then they mostly
cruise around the mountains a bit like you might take a stroll with the
dog. Wear a helmet, and you're unlikely to suddenly break into a trot as
a result, or start climbing trees.

| I think we're talking in circles here. The issue is whether people
| adjust their behaviour in accordance with a perceived change in
risk.
|
| Which at a population level there is plenty of evidence for.

At population level? I've never suggested there wasn't, only referring
to a small sector of the skiing public with reference to the wearing of
helmets..

| I pointed out that with respect to the *real* (not Slush 'n Rubble)
| experts, or with respect to knowledgeable mountain-dwelling locals,
| any change in behaviour would in my view be negligeable or
| non-existent.
|
| But the question is are local knowledgeable, skilled people at much
| lower risk of injury? You might need to calculate risk per day of
skier
| exposure to compensate for increased time of exposure.
|
| There are clearly many more visitors than locals on the slopes, but
are
| the locals at much less risk per day of skiing than all the visiting
| groups?

On a risk per day level? I would think hugely so, if you compare like
with like (leisure skiing). There are lots of factors involved - so
obviously generalising to an extent... all season round local skiers are
fitter. They have extensive local knowledge - of the terrain, weather
and snow conditions. Many have taken lessons, go skiing with instructors
who are part of the family, clipped on their skis when they were 2 and
haven't looked back since. They don't push it in the same way as
visitors are sometimes tempted to do on their short and expensive trip
to the snow. They can afford to wait for a few days after a heavy dump
to head off piste. They understand the warning signs - a lot of visitors
don't.

It's more complicated with that (different age groups etc need to be
studied), but that's my perception.

A British BASI 1 instructor of my acquaintance based in 2 Alpes once put
it something like this... 'Just as there's a very large gap in skill
between a first week tourist beginner and me, there's at least as large
a gap between me and a world class freerider or a Hermann Maier.' I just
don't think a self-proclaimed 'advanced' week or two a year skier is
using the same scale as the locals, who might consider themselves
'pretty good', but no more - they know what being expert really means..

| I suggested that with respect to a child who has never known
anything
| else, he would not be taking increased risks when compared to a
| hypothetical identical child brought up to an identical skiing
| standard without ever wearing a helmet.
|
| Yes because they will have both reached a risk homeostasis that they
| were comfortable with.
|
| The point about this that you don't seem to be accepting is that the
| introduction of measures to improve safety don't seem to always result
| in expected improvement in safety when you look at the data.

You'll find that I've never claimed that, except with respect to ski
racers, and to a lesser extent, lifelong mountain dwellers.

| The question is whether there is any statistical evidence to test this
| out with respect to injuries in skiing? Do you know whether injuries
| amongst racers have decreased or increased over time and as equipment
| has changed?
|
| From a quick search through the literature I've only found a few
studies
| but the one you have copied on the snowsport website certainly seems
to
| provide evidence consistent with "risk compensation" amongst skiers
and
| boarders.

I've not disputed that it doesn't play a role except with reference to
one particular (small) group of skiers. I think the significance with
respect to tourist skiers may be relatively small, possibly even
negligible set alongside the potential benefits, especially if provided
with better education and information, and after the passage of time -
but that's another discussion.

"Ace" wrote in message
...
| On Thu, 18 Jan 2007 16:00:16 +0100, "pg"
| wrote:
|
|
| "Mike Clark" wrote in message
| c.uk...
| | In message
| | "pg" wrote:
| |
| | [snip]
| | Still, given that they were spending the whole day entirely on
piste
| |
| | It's not unknown of for an avalanche to cross a piste.
|
| On that particular day in Les Arcs? For 3 cms of ice embedded between
| the exposed rocks to avalanche on a cold, overcast day, you would
have
| to be damn unlucky...
|
| But as we've said before, are we all qualified to make that sort of
| judgement every single day we go out on the mountain? I'd much rather
| wear the thing all the time and get laughed at than risk making the
| wrong choice and getting avalanched.

True ... I suppose it's a move in the right direction, all things
considered. Didn't stop it looking funny though ;-)

Pete
http://mysnowsports.com

In message
"pg" wrote:

[snip]
In the (only) group I have been discussing (ski racers / mountain
dwellers), I reckon the effect - if any - would be negligible.


The simple way to demonstrate that you are right would be to show that
mountain dwellers and ski racers were at much less risk than you'd
expect from the general population. I'd hypothesise that if you did find
such data that you'd find that ski racers and mountain dwellers are
likely to be at a higher risk than the general population because
familiarity with risk tends if anything to make people less cautious.

As to ski racers being immune from "risk compensation" ask yourself this
simple question. Do you think that ski racers are more or less likely to
be injured whilst recreational skiing or whilst racing or training?

Mike
--
o/ \\ // |\ ,_ o Mike Clark
\__,\\ // __o | \ / /\, "A mountain climbing, cycling, skiing,
" || _`\,_ |__\ \ | immunology lecturer, antibody engineer and
` || (_)/ (_) | \corn computer user"