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Can't Use Helmets in the Sun????



 
 
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  #141  
Old May 23rd 06, 09:30 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

GaryG wrote:

By that "rationale", a cotton cycling cap would confer a greater degree of
protection than a proper cycling helmet. Not sure if that's the argument
you're trying to make, but that's the take-home message.


It depends on the accident. If the accident is one where a capped head
comes within an inch of an obstacle but a helmeted head hits it, then
that would indeed be the case. Another possibility is that a capped
head ends up concussed and grazed but a helmeted head is twisted by the
extra leverage allowed by the helmet and has its neck broken. But you
don't know if that would be the case up front, of course...

The take-home message is you cannot say for sure that after an accident
you were *surely* better off with a helmet, simply on the grounds that
it hit something. You might be, but you won't /definetly/ be.

FWIW, the average human head weighs between 4.5 and 5 kg. An average
bicycle helmet (e.g., Gyro Pneumo) weighs 0.26 kg, so the average increase
in head weight is around 5%.

You've implied in quite a few posts that an unhelmeted cyclist can keep
their head from impacting the ground in a fall by use of their neck muscles,
and you've also stated that a helmeted cyclist's neck muscles would not be
able to overcome the additional momentum of the helmet. Given the small
additional mass of a modern helmet, I strongly suspect your argument is
specious (a nice way of saying you're pulling it out of your ass).


It's not just weight, it's size too. You'd have an easier job keeping
an unhelmeted head off the deck than a zero weight helmet because you
don't have to keep it up the extra distance required by the additional
size of the helmet.
The head is kept up by reflex action, and the reflexes are working on a
self-knowledge of where the head is and extends to. Unless you make a
habit of sliding around tarmac in a cycle helmet then the reflex to keep
the head up is using information on the head, not the helmeted head.

This is quite easy to see safely in practice: wear a helmet in a cave
and you'll bang your head far more often than if you don't (though in
this case since you'll almost certainly be banging it anyway, and are
never above walking pace, it's definitely worth wearing!).

Yet again the clear message is that "helmets are dangerous".


No, it is that they are *potentially* dangerous and are *not* a clear win.

Do you have any studies to back up your rather bizarre assertions that
helmets increase the dangers of head impact/neck injuries? Or, is this
merely yet more of your anti-helmet crusade?


Go to www.cyclehelmets.org and get reading.

For example, you can find one that suggests you're 7 times more likely
to hit your head in a crash with a helmet than without in
Wasserman RC, Waller JA, Monty MJ, Emery AB, Robinson DR. Bicyclists,
helmets and head injuries: a rider-based study of helmet use and
effectiveness. 1988. American Journal of Public Health: 1988
Sep;78(9):1220-1

Not a study, but an expert opinion you'll find there is, "the very
eminent QC under whose instruction I was privileged to work, tried
repeatedly to persuade the equally eminent neurosurgeons acting for
either side, and the technical expert, to state that one must be safer
wearing a helmet than without. All three refused to so do, stating that
they had seen severe brain damage and fatal injury both with and without
cycle helmets being worn. In their view, the performance of cycle
helmets is much too complex a subject for such a sweeping claim to be made."

It isn't an anti-helmet crusade, it's a get real about the realities of
what you can really expect crusade. If I was "anti helmet" I wouldn't
own and occasionally wear one.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
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  #142  
Old May 23rd 06, 03:01 PM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

"Peter Clinch" wrote in message
...
GaryG wrote:

By that "rationale", a cotton cycling cap would confer a greater degree

of
protection than a proper cycling helmet. Not sure if that's the

argument
you're trying to make, but that's the take-home message.


It depends on the accident. If the accident is one where a capped head
comes within an inch of an obstacle but a helmeted head hits it, then
that would indeed be the case. Another possibility is that a capped
head ends up concussed and grazed but a helmeted head is twisted by the
extra leverage allowed by the helmet and has its neck broken. But you
don't know if that would be the case up front, of course...

The take-home message is you cannot say for sure that after an accident
you were *surely* better off with a helmet, simply on the grounds that
it hit something. You might be, but you won't /definetly/ be.

FWIW, the average human head weighs between 4.5 and 5 kg. An average
bicycle helmet (e.g., Gyro Pneumo) weighs 0.26 kg, so the average

increase
in head weight is around 5%.

You've implied in quite a few posts that an unhelmeted cyclist can keep
their head from impacting the ground in a fall by use of their neck

muscles,
and you've also stated that a helmeted cyclist's neck muscles would not

be
able to overcome the additional momentum of the helmet. Given the small
additional mass of a modern helmet, I strongly suspect your argument is
specious (a nice way of saying you're pulling it out of your ass).


It's not just weight, it's size too. You'd have an easier job keeping
an unhelmeted head off the deck than a zero weight helmet because you
don't have to keep it up the extra distance required by the additional
size of the helmet.
The head is kept up by reflex action, and the reflexes are working on a
self-knowledge of where the head is and extends to. Unless you make a
habit of sliding around tarmac in a cycle helmet then the reflex to keep
the head up is using information on the head, not the helmeted head.


The reflex to keep one's head off the deck does not concern itself with an
extra 2 cm of radius...it's a neuromuscular response, and the response is to
keep the head up as much as possible, regardless of size or headgear. To
imply that a helmeted head will smack the ground with force, because one's
reflexive reaction to an impending impact miscalculated the additional
effective head size occasioned by the helmet is simply ludicrous.


This is quite easy to see safely in practice: wear a helmet in a cave
and you'll bang your head far more often than if you don't (though in
this case since you'll almost certainly be banging it anyway, and are
never above walking pace, it's definitely worth wearing!).


True perhaps, but that's not at all the same as the reflexive reactions to
protect one's skull that occur during falls.


Yet again the clear message is that "helmets are dangerous".


No, it is that they are *potentially* dangerous and are *not* a clear win.

Do you have any studies to back up your rather bizarre assertions that
helmets increase the dangers of head impact/neck injuries? Or, is this
merely yet more of your anti-helmet crusade?


Go to www.cyclehelmets.org and get reading.

For example, you can find one that suggests you're 7 times more likely
to hit your head in a crash with a helmet than without in
Wasserman RC, Waller JA, Monty MJ, Emery AB, Robinson DR. Bicyclists,
helmets and head injuries: a rider-based study of helmet use and
effectiveness. 1988. American Journal of Public Health: 1988
Sep;78(9):1220-1

Not a study, but an expert opinion you'll find there is, "the very
eminent QC under whose instruction I was privileged to work, tried
repeatedly to persuade the equally eminent neurosurgeons acting for
either side, and the technical expert, to state that one must be safer
wearing a helmet than without. All three refused to so do, stating that
they had seen severe brain damage and fatal injury both with and without
cycle helmets being worn. In their view, the performance of cycle
helmets is much too complex a subject for such a sweeping claim to be

made."

It isn't an anti-helmet crusade, it's a get real about the realities of
what you can really expect crusade. If I was "anti helmet" I wouldn't
own and occasionally wear one.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/



  #143  
Old May 23rd 06, 04:12 PM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
external usenet poster
 
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Default Can't Use Helmets in the Sun????

GaryG wrote:

The reflex to keep one's head off the deck does not concern itself with an
extra 2 cm of radius...it's a neuromuscular response, and the response is to
keep the head up as much as possible, regardless of size or headgear.


Quite so, but the muscles and overall physiology and what is needed to
keep one's head safe (and thus capable of passing one's genes on) is
supported by several million years of evolution of not being bigger than
it is, which isn't the case with heads in helmets (i.e., if the head
needed picking up more than it does there may have been reasons to
evolve more effective means of doing so, but you won't develop such
mechanisms just for the sake of it).

As the publication I pointed to suggests, there *is* evidence that
you're considerably more likely to hit your head, however "ludicrous"
what I happen to be saying.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
  #144  
Old May 23rd 06, 04:28 PM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

Peter Clinch wrote:
GaryG wrote:

The reflex to keep one's head off the deck does not concern itself
with an extra 2 cm of radius...it's a neuromuscular response, and
the response is to keep the head up as much as possible, regardless
of size or headgear.


Quite so, but the muscles and overall physiology and what is needed to
keep one's head safe (and thus capable of passing one's genes on) is
supported by several million years of evolution of not being bigger
than it is, which isn't the case with heads in helmets (i.e., if the
head needed picking up more than it does there may have been reasons
to evolve more effective means of doing so, but you won't develop such
mechanisms just for the sake of it).


So the more we wear helmets the safer we'll be, evolution-wise. LOL


  #145  
Old May 23rd 06, 08:12 PM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

Sorni wrote:

So the more we wear helmets the safer we'll be, evolution-wise. LOL


In the long term if wearing them enhances your ability to both
reproduce and be safe, probably...

I'll freely admit I wasn't too coherent in my arguments here, let's
try again:

It is natural to try and keep your head away from impacts by reflex.
Reflex action will try and keep your head as far away fromn the
deck as possible.
It does not always succeed, therefore there are times when the
muscles cannot keep the head off the deck.
Those situations are more likely to crop up with a bigger and
heavier head.
In any given crash, a bigger and heavier head is more likely to
take a hit than an otherwise smaller and lighter one.

How's that?

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
  #146  
Old May 24th 06, 03:24 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Posts: n/a
Default Can't Use Helmets in the Sun????

"Peter Clinch" wrote in message
...
Sorni wrote:

So the more we wear helmets the safer we'll be, evolution-wise. LOL


In the long term if wearing them enhances your ability to both
reproduce and be safe, probably...

I'll freely admit I wasn't too coherent in my arguments here, let's
try again:

It is natural to try and keep your head away from impacts by reflex.
Reflex action will try and keep your head as far away fromn the
deck as possible.
It does not always succeed, therefore there are times when the
muscles cannot keep the head off the deck.
Those situations are more likely to crop up with a bigger and
heavier head.
In any given crash, a bigger and heavier head is more likely to
take a hit than an otherwise smaller and lighter one.

How's that?


If helmets were 1 meter in diameter, and made out of stainless steel, you
might have an argument.

But given that helmets only add about 2 cm of radius and 5% additional mass,
I still think your arguments in this regard have no merit whatsoever...they
are, at best, mere speculation with nothing whatsoever to back them up.

Nevertheless, if my reflexes fail to keep my head from hitting the ground in
a fall (due to the type of fall, the force or angle of the fall, etc.), I'd
much rather have a helmet absorb the initial impact instead of my
unprotected scalp.

GG


Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/



  #147  
Old May 24th 06, 05:14 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
external usenet poster
 
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Default Can't Use Helmets in the Sun????

GaryG wrote:
"Peter Clinch" wrote in message
...

Sorni wrote:


So the more we wear helmets the safer we'll be, evolution-wise. LOL


In the long term if wearing them enhances your ability to both
reproduce and be safe, probably...

I'll freely admit I wasn't too coherent in my arguments here, let's
try again:

It is natural to try and keep your head away from impacts by reflex.
Reflex action will try and keep your head as far away fromn the
deck as possible.
It does not always succeed, therefore there are times when the
muscles cannot keep the head off the deck.
Those situations are more likely to crop up with a bigger and
heavier head.
In any given crash, a bigger and heavier head is more likely to
take a hit than an otherwise smaller and lighter one.

How's that?



If helmets were 1 meter in diameter, and made out of stainless steel, you
might have an argument.

But given that helmets only add about 2 cm of radius and 5% additional mass,
I still think your arguments in this regard have no merit whatsoever...they
are, at best, mere speculation with nothing whatsoever to back them up.

Nevertheless, if my reflexes fail to keep my head from hitting the ground in
a fall (due to the type of fall, the force or angle of the fall, etc.), I'd
much rather have a helmet absorb the initial impact instead of my
unprotected scalp.

GG


Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/





WTF? Cross-posting to rec.bicycles.marketplace?!?

Aren't you worried about all the other potentially fatal wounds you
might receive in an accident? How do those risks compare to those from
head injuries?


Robin Hubert
  #148  
Old May 24th 06, 06:34 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Posts: n/a
Default Can't Use Helmets in the Sun????

In article ,
"GaryG" wrote:

"Peter Clinch" wrote in message
...
It is natural to try and keep your head away from impacts by reflex.
Reflex action will try and keep your head as far away fromn the
deck as possible.
It does not always succeed, therefore there are times when the
muscles cannot keep the head off the deck.
Those situations are more likely to crop up with a bigger and
heavier head.
In any given crash, a bigger and heavier head is more likely to
take a hit than an otherwise smaller and lighter one.

How's that?


If helmets were 1 meter in diameter, and made out of stainless steel, you
might have an argument.

But given that helmets only add about 2 cm of radius and 5% additional mass,
I still think your arguments in this regard have no merit whatsoever...they
are, at best, mere speculation with nothing whatsoever to back them up.


I wear a hard hat, and always clank it into stuff. I will
say to myself, "Self, you are wearing a hard hat. Watch
your step." For a while that works, then I stop devoting
attention to such a ridiculous thought: that my head is
bigger than it is. Ludicrous. Then Blam! I smacked it into
something again. I have been wearing eyeglasses for
decades, and still knock theem off in close quarters. We
really have hardwired into us how big our head is. Even a
billed cap is knocked askew, as often as not.

Nevertheless, if my reflexes fail to keep my head from hitting the ground in
a fall (due to the type of fall, the force or angle of the fall, etc.), I'd
much rather have a helmet absorb the initial impact instead of my
unprotected scalp.


If I had not been wearing that impossible hard hat, I
would never have knocked it or my head into solid objects.
Noone will mistake me for Mikhail Baryshnikov, yet I do
not smack my unadorned head into solid objects; not at
all.

--
Michael Press
  #149  
Old May 24th 06, 09:01 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

GaryG wrote:

If helmets were 1 meter in diameter, and made out of stainless steel, you
might have an argument.

But given that helmets only add about 2 cm of radius and 5% additional mass,
I still think your arguments in this regard have no merit whatsoever...


Bigger is bigger is bigger. It is hard to keep something bigger from
hitting the deck given the same support.

are, at best, mere speculation with nothing whatsoever to back them up.


It's hardly "mere speculation" that bigger targets are easier to hit.

What about the paper I suggested?

Nevertheless, if my reflexes fail to keep my head from hitting the ground in
a fall (due to the type of fall, the force or angle of the fall, etc.), I'd
much rather have a helmet absorb the initial impact instead of my
unprotected scalp.


Fine, but that's not the point at hand. Yes, if someone whacks me over
the head with a baseball bat I'd sooner be wearing a helmet than a
cycling cap. But if the bat is swung vigorously 1cm away from my head
then the fact is the helmet /then/ makes me worse off.

Which it wouldn't do if it was /only/ ever a benefit or totally irrelevant.

Thus, you cannot say for /sure/ that in an accident you must be better
off with a helmet.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
  #150  
Old May 24th 06, 10:02 AM posted to alt.rec.bicycles.recumbent,rec.bicycles.tech,rec.bicycles.marketplace,rec.bicycles.misc
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Default Can't Use Helmets in the Sun????

Peter Clinch wrote:

Bigger is bigger is bigger. It is hard to keep something bigger from
hitting the deck given the same support.


typo time
That should be hard/er/, rather than just hard
/typo time

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/
 




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