Stupid helmet question ...

In message
"pg" wrote:


"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.

On that specific question of what you regard as "experts" and "helmet
wearing" I don't think either of us have yet been able to find data that
addresses the specific point. However in other fields where it has been
looked at "experts" do "risk compensate".

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.

Yes but despite the lack of objective criteria on ability in the
Norwegian study it is still likely that there will be a reasonable
correlation with subjective criteria. For example there must be some who
you would classify as expert in that study since it covered 19 of the 20
Norwegian resorts for the whole season and the sampling of controls was
simply every 10th person in the queue. Do you think those real "experts"
would be likely to self classify as beginner, intermediate, good or
expert? Equally do you think that those who were beginners would be more
or less likely to self classify as beginner, intermediate, good or
expert?

But more telling in that study is that the wearing of a helmet is
associated with risk taking. Self confessed risk takers are more likely
to wear a helmet, OR 1.4





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.

Do mountain dwellers and professionals have accidents? Are they
statistically at more or less risk than the general population?

That's the data that is needed to try to address the question.



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.

What about putting on a transceiver? If a local or expert skier is asked
to go off piste would they be more likely to do so if they wore a
transceiver than if they had left it at home?


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..


The only real way to address your specific point would be to randomly
select race skiers in competition and at different events to get some to
wear a helmet and others not to. Over a period of time you could collect
data on the relative performance with and without 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).

Sorry but that is ducking the issue. The whole point about risk
compensation is that you aren't comparing like with like because of the
change in behaviour. As the skill of an individual increases they are
more likely to increase their exposure to risk. They don't devote the
same proportion of their time to exposure to a lower level of risk.

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.

All these factors are relevant and interesting, but the bottom line is
do local people with local knowledge and expertise ever suffer death or
injury?

What is their actuarial risk?

Amongst ski-racers it is clear that the risk of injury is very high
since a high proportion of them retire for major medical treatment each
season. If that isn't an indication of risk taking behaviour I don't
know what is.


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

The Norwegian study did also look at age as a factor and shows that
13-20 year olds are at much higher risk than those over 20.


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.

So according to you ski racers and lifelong mountain dwellers rarely
have accidents and rarely have injuries? They don't take risks and
always ski well within their abilities with plenty of safety margin?

Yet at the same time you've argued that all of them have close
acquaintances that have been injured or killed in the mountains. How do
you reconcile your apparent conflicting statements?


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.


Yes but from the Norwegian study it would appear that the group
suffering the lowest accident statistics are "intermediates". If you
educate them more then they become better skiers and the accident
statistics increase!

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

On Fri, 19 Jan 2007 12:27:14 GMT, Mike Clark
wrote:

On that specific question of what you regard as "experts" and "helmet
wearing" I don't think either of us have yet been able to find data that
addresses the specific point. However in other fields where it has been
looked at "experts" do "risk compensate".

It's a well known stat that the more experienced you are in the
mountains, the more likely you are to die in an avalanche.


--
Champ

In message , Pip Luscher
writes
On Thu, 18 Jan 2007 13:26:27 GMT, Mike Clark
wrote:

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.

"Why did the avalance cross the piste?"

To get to the Iceland shop? No you're right, it doesn't work.
--
Devs
"Punchdown Pete the old Kroner"

In message , Ace
writes
Some may laugh, but there are several reasons for it, including:
1. We see it as much as an educational thing as a short-term dafety
issue - getting punters to be aware that there is always a risk and
that we should always do what we can to minimise it is a lesson worth
teaching.
2. Dunno about you, but I've seen avalanches occuring in Risk 1
conditions - 1 doesn't mean no risk at all, just that it's the lowest
measure used.
3. If you don't wear your ARVA every day, how do you make a decision
as to which days to wear it? I've even known people who don't put it
on but carry it (not switched on) in their rucksack 'just in case'.
How stupid is that?
4. We have to cart the things out to the resort with us, so we're damn
well gonna make the punters wear them ;-)

So some folk may laugh, but do we care? Do we 'eck, as like.

I'm really confused by your opposed attitudes to transceivers and
helmets. Both of them could potentially save your life or be useless
unwanted extra luggage but you have entirely different attitudes to each
of them. Strange. Personally I wear a helmet every time I'm off piste
and most of the time on it these days. I'll wear a transceiver as soon
as i can afford it, but only on "proper " off piste.
--
Devs
"Punchdown Pete the old Kroner"

In message , Adrian D. Shaw
writes
If I were the type of skier who slalom-raced off piste through the
forests of the lower slopes, I guess I would wear a helmet. But anything
which makes me feel safer is likely to make me more reckless, and I'd
rather feel my true vulnerability.

I saw my friend graze his head recently - after the branch had pushed
all the way through his helmet. If it wasn't there he certainly would
never suffer from a pressure headache again! He was on a flat, green if
you like, but after a storm had overhung a tree across the track. What
are the chances? Doesn't matter, if it saves him once it's worth it.
Rugby helmets and shoulder pads make people run into impact harder? Not
in my experience but then I do wear the pads on the insistence of a lady
who doesn't like me with scabby ears and shoulders!
Worst injury I've ever seen? Someone skiing with a metal sided brace
because of ligament damage losing it on moguls.
Safety equipment will help in the majority of accidents. If you adjust
your performance accordingly you are a fool.
--
Devs
"Punchdown Pete the old Kroner"

"Champ" wrote in message
...
| On Fri, 19 Jan 2007 12:27:14 GMT, Mike Clark
| wrote:
|
| On that specific question of what you regard as "experts" and "helmet
| wearing" I don't think either of us have yet been able to find data
that
| addresses the specific point. However in other fields where it has
been
| looked at "experts" do "risk compensate".
|
| It's a well known stat that the more experienced you are in the
| mountains, the more likely you are to die in an avalanche.

Well, for stating the blindingly obvious, that takes the biscuit. It's
also a well known fact that guides, other mountain professionals,
experienced locals etc, spend many, many times more skier hours on the
snow and off piste than your average punter (some putting themselves at
risk to look after/rescue said punters). Ditto, those that push it to
the limit in sporting terms - because that's the only way you can win.

But we were discussing helmets. These guys above are not going to take
extra risks because they've got a layer of tin on their heads partially
protecting them from glancing blows, and direct impacts up to around 15
mph. They're doing their jobs, and would do them with or without
helmets.

Another report that should be looked at is the Hagel study -
http://www.bmj.com/cgi/content/full/330/7486/281

"Helmets may reduce the risk of head injuries in skiers and snowboarders
by 29% to 56%"

From the Levy study "An Analysis of Head Injuries among Skiers and
Snowboarders":

" In over 400 skiers and snowboarders with TBIs (traumatic brain
injuries) serious enough to warrant transfer and admission to our level
I trauma center, only five were wearing helmets. All five patients had
mild injuries and made full recoveries despite some very major
mechanisms. Our most severely injured helmeted patient to date was a
snowboarder who went off a 40 foot cliff and landed on his head,
cracking his helmet in half. He sustained a severe concussion (or mild
diffuse axonal injury) with loss of consciousness, but had a negative CT
scan of the head. He did require inpatient rehabilitation, but
ultimately has made a full recovery and is now attending college. All
the rest of the helmeted skiers and snowboarders had mild concussions
and negative CT scans. Among the unhelmeted only 69% had simple
concussions with negative CT scans of the head. The rest had more severe
injuries such as cerebral contusions, or subdural, epidural or
intracerebral hematomas. Severe TBI, with coma and Glasgow Coma Scale
(GCS) score of 3-8, occurred in 15% of the unhelmeted skiers and
snowboarders with head injuries, and their overall mortality rate after
admission to the hospital was 4%."

On Sat, 20 Jan 2007 11:02:24 +0100, "pg"
wrote:


"Champ" wrote in message
...
| On Fri, 19 Jan 2007 12:27:14 GMT, Mike Clark
| wrote:
|
| On that specific question of what you regard as "experts" and "helmet
| wearing" I don't think either of us have yet been able to find data
that
| addresses the specific point. However in other fields where it has
been
| looked at "experts" do "risk compensate".
|
| It's a well known stat that the more experienced you are in the
| mountains, the more likely you are to die in an avalanche.

Well, for stating the blindingly obvious, that takes the biscuit.

proud

But we were discussing helmets. These guys above are not going to take
extra risks because they've got a layer of tin on their heads partially
protecting them from glancing blows, and direct impacts up to around 15
mph.

This is, of course, the argument. I can't really see how you can be
so utterly convinced that, in every case, an experienced mountain user
will not change their behaviour with a helmet on.

From the Levy study "An Analysis of Head Injuries among Skiers and
Snowboarders":

" In over 400 skiers and snowboarders with TBIs (traumatic brain
injuries) serious enough to warrant transfer and admission to our level
I trauma center, only five were wearing helmets. All five patients had
mild injuries and made full recoveries despite some very major
mechanisms. Our most severely injured helmeted patient to date was a
snowboarder who went off a 40 foot cliff and landed on his head,
cracking his helmet in half. He sustained a severe concussion (or mild
diffuse axonal injury) with loss of consciousness, but had a negative CT
scan of the head. He did require inpatient rehabilitation, but
ultimately has made a full recovery and is now attending college. All
the rest of the helmeted skiers and snowboarders had mild concussions
and negative CT scans. Among the unhelmeted only 69% had simple
concussions with negative CT scans of the head. The rest had more severe
injuries such as cerebral contusions, or subdural, epidural or
intracerebral hematomas. Severe TBI, with coma and Glasgow Coma Scale
(GCS) score of 3-8, occurred in 15% of the unhelmeted skiers and
snowboarders with head injuries, and their overall mortality rate after
admission to the hospital was 4%."


shocked Are you suggesting that a helmet might protect the wearer
from head injuries? Good god, man, why didn't you say so before!
--
Champ

On Sat, 20 Jan 2007 01:40:20 +0000, Devs
wrote:

In message , Adrian D. Shaw
writes
If I were the type of skier who slalom-raced off piste through the
forests of the lower slopes, I guess I would wear a helmet. But anything
which makes me feel safer is likely to make me more reckless, and I'd
rather feel my true vulnerability.

I saw my friend graze his head recently - after the branch had pushed
all the way through his helmet. If it wasn't there he certainly would
never suffer from a pressure headache again! He was on a flat, green if
you like, but after a storm had overhung a tree across the track. What
are the chances? Doesn't matter, if it saves him once it's worth it.
Rugby helmets and shoulder pads make people run into impact harder? Not
in my experience but then I do wear the pads on the insistence of a lady
who doesn't like me with scabby ears and shoulders!
Worst injury I've ever seen? Someone skiing with a metal sided brace
because of ligament damage losing it on moguls.
Safety equipment will help in the majority of accidents. If you adjust
your performance accordingly you are a fool.

Many studies suggest that, in your words, everyone is foolish.
--
Champ

"Mike Clark" wrote in message
.uk...
| 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.

So you would be safer being driven along a wet country road with 'Mr
Ordinary Sunday driver' at the wheel, than as Michael Schumacher's
passenger? More secure than on a winding, icy road sitting next to
Sebastien Loeb? Take racing and training out of the equation, and I
would wager that this target group are at a greatly reduced risk level.
Because one can go very quickly indeed doesn't mean than one is
compelled to. Beyond a certain age this is certainly not the case (I
would guess 30/35+), and amongst the younger generations, they quickly
gain a maturity and understanding of the genuine risks involved, of
which most holiday skiers are unaware.

Your hypothesis above completely ignores training, skill, fitness,
familiarity with terrain, snow conditions and weather, knowledge of how
to fall, instinctive awareness of what you can and cannot take on. It
also ignores certain negative factors adversely affecting the short
holiday skier on a quick dash to the snow.

| 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?

Vastly less, obviously. But I've only (throughout) been referring to
relative immunity *with respect to the wearing, or otherwise, of a
helmet, by genuinely expert skiers.* You're shifting the goal posts.
With respect to ski racing/training we're talking about calculated risks
consciously taken, not the hypothetical ones skiers may or may not take
on unconsciously when they don a helmet.

I flippantly questioned - with respect to a ski racer who has worn a
helmet since he first slid down a slope - whether wearing a different
colour pair of socks would encourage him to ski with a different
(safer/less safe) attitude. If the answer is no, then you prove my
point. To a ski racer a helmet is an item of clothing, part of the
uniform, no more, no less.

With respect to risk compensation and lids across skiing as a whole, you
might be interested in this brief summary of a study. It has an
interesting conclusion: "Helmet use by skiers and snowboarders continued
to trend upwards and does not appear to motivate more risk taking.
Helmet wearers engaged in less risk behavior than non-wearers,
suggesting that decisions to adopt helmets are motivated by safety
concerns."

http://www.cdc.gov/NCIPC/lifeguard/2...stractBook.pdf (a
very large pdf).

On page 148 there a piece entitled: "Testing the Risk Compensation
Hypothesis for Safety Helmets in Alpine Skiing and Snowboarding".

Michael D Scott, PhD1, DB Buller, PhD2, PA Andersen, PhD3, BJ Walkosz,
PhD4, JH Voeks, PhD5, MB Dignan, PhD6, GR Cutter, PhD5
1California State University, Chico, CA; 2The Cooper Institute, Denver,
CO; 3San Diego State University, San Diego, CA; 4University of Colorado,
Denver, CO; 5University of Alabama, Birmingham, AL; 6University of
Kentucky, Lexington, KY

"Background/Objectives: Previous surveys showed increasing adoption of
helmets by skiers and snowboarders. Efficacy of helmets for these sports
has been questioned on the basis of risk compensation. This survey
tracked helmet use by skiers and snowboarders and tested for risk
compensation.

Methods: Helmet use was recorded in face-to-face interviews with 1,779
adult skiers and snowboarders at 31 ski areas in Western North America
in January-March 2003. Respondents were asked two questions assessing
risk compensation: do they (a) ski/snowboard faster, slower or about the
same speed and (b) challenge themselves more, less or about the same.
Helmet wearers compared current behavior to when they did not wear a
helmet; non-wearers, to previous seasons.

Results: In 2003, 23.0% were observed to be wearing a helmet (12.1% in
2001; 19.6% in 2002). Significant univariate predictors of use (p.05)
were included in a multivariate logistic regression to identify the
strongest predictors of higher use: older guests (O.R. = 1.02, p.05),
snowboarders (O.R. = 3.24, p.05), guests with a college degree (O.R. =
1.73, p.05), and those who spent more days on the mountain (O.R. =
3.18-8.03, p.05). Helmet use was significantly associated with less
risky skiing/snowboarding (higher speeds, O.R. = 0.64, 95% C.I. 0.49,
0.82; more challenge, O.R. = 0.76, 95% C.I. 0.60, 0.97) compared to no
use. A minority reported engaging in more risky skiing/snowboarding
(33.6% faster; 35.7% challenge), but this was associated with variables
other than helmet use.

Conclusions: Helmet use by skiers and snowboarders continued to trend
upwards and does not appear to motivate more risk taking. Helmet wearers
engaged in less risk behavior than non-wearers, suggesting that
decisions to adopt helmets are motivated by safety concerns. "

"Mike Clark" wrote in message
.uk...
| In message
| "pg" wrote:
|
| [snip]
| I used to ski without. I now ski with. I ski in precisely the same
way.
| The only consequence of wearing a helmet has been to get used to it.
| Having got used to it, I would feel different without it, for a
limited
| period of time, until I got used to skiing without it again. I would
| then be back to skiing in precisely the same manner.
|
|
| But that is what you expect to observe with "risk homeostasis". If you
| make a change it only has a temporary effect and then the individuals
| tend to adjust to how they behaved before.

? This has been a pretty pointless discussion then!