Helmets

gotbent said:

Having done a bit of package design and gotten a rudimentry education in
what foam does, I think that the breaking strength of the skull is a poor
metric in a discussion of how a helmet protects you. I believe the purpose
of a helmet is to decrease the g loading on the brain by absorbing energy so
that the grey stuff doesn't slam into the skull case which is the thing that
causes damage.

Well, that's fine, but serious head injury rates amongst cyclists are
unchanged when the helmet wearing rates go up (even when they go
dramatically up, < ~40% to > ~80% more or less overnight). Which rather
strongly suggests that whatever the design and intended purpose might
be, the net effect is basically Zip.

Furthermore, the same design principles are just as relevant to trips
and falls and road traffic accidents on foot, yet pedestrians never wear
them, but they /do/ sufer serious head injuries at a similar rate to
cyclists. The differences are perception and FUD rather than real.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Roger Zoul said:

Ben Goren wrote:
:: Roger Zoul wrote:
::
::: Ben Goren wrote:
:::
:::: What the aero shapes /do/ do is twist your head around when
:::: you hit the ground, possibly snapping your neck in extreme
:::: cases. The Citi is round and has no snag points (mounting
:::: brackets, rough finishes, oversized vents with sharp corners,
:::: etc.) It's also available in a day-glo orange.
:::
::: Is this based on theory or is there anything more? (not being
::: critical or trying to incite - just stupidly curious)
::
:: It's mostly from the Bicycle Helmet Safety Institute at:
::
:: http://www.helmets.org/
::
:: In particular, be sure to check out their recommendations for the
:: 2007 season.
::
:: The fact that the Citi is a Consumer Reports best buy doesn't
:: hurt, either....

Thanks. I could not find on the Bell website any info on a day-glo orange
helmet. Any leads?
I'm going to check out CR next.

I went for the Bell Metropolis fits well with the knob one step
adjustment and doesn't get in the way of my neck rest.

Ben Goren said:

Quoted message said:

Ben Goren said:

It's mostly from the Bicycle Helmet Safety Institute at:

http://www.helmets.org/

In particular, be sure to check out their recommendations for
the 2007 season.

Impressive! I was trying to be funny rhyming Bell,but that was
such good info; I ****will**** get a Bell :-) - thanks for the
link.

Well, don't just take my word for it; for something as important
as a helmet, it behooves you to do your full due diligence. And be
sure to try the helmet on your head before buying it! It's useless
if it doesn't fit properly.

But I am generally impressed with what I've learned about the
Citi, enough that the fit test is about the only one left that'll
sway me one way or the other.

Unless, of course, I discover something even better. Frankly, I'm
almost wondering if some of those helmets that meet /both/ skating
and cycling standards might not make even more sense....

Cheers,

b&

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head. I don't ride even
my trike without a helmet.

"Joel" <joelw135atcomcast.net> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head. I don't ride even my
trike without a helmet.

You would have broken your thumb?

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Joel joelw135atcomcast.net said:

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head.

If the helmet cracked, but you suffered no injury, I would guess you'd
have got a bit grazed. The helmet clearly did not absorb much energy
(cracking fracture being a low energy failure mode).

Possibly you'd have escaped all injury, since it seems you hardly hit
the ground - your head might have missed the ground without a big
hat.

You can't know is the answer. So relying on this event as proof of
something (anything) is nonsense.

regards, Ian SMith
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|o o|
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gotbent said:

"Joel" <joelw135atcomcast.net> wrote in message
news:[email hidden]...

Quoted message said:

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head. I don't ride even my
trike without a helmet.

You would have broken your thumb?

Maybe, or maybe nothing much, or maybe death. Who knows?

Was there amazing head related carnage amongst cyclists before the
introduction of helmets? No. Yet ever since their introduction,
although the serious injury rates haven't moved much, they are,
apparently, responsible for saving countless lives. Doesn't really add
up for hats being lifesavers.

Oddly, places like NL and Denmark where the wearing rates are incredibly
low also have the lowest cyclist head injury rates, despite their
much-vaunted fietspads not being any proof against falling off cornering
like the above incident. Doesn't really add up for hats being lifesavers.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

"Ian Smith" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Joel joelw135atcomcast.net said:

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head.

If the helmet cracked, but you suffered no injury, I would guess you'd
have got a bit grazed. The helmet clearly did not absorb much energy
(cracking fracture being a low energy failure mode).

If the area around the crack shows compression, then the foam absorbed and
dissapated energy. However if there is only a crack then it didn't.

In the case where I impacted my head, the foam along the area of my left
temple was quite compressed. I still have that momento somewhere in the
garage as a souvinire and could dig it out, but IIRC there is an area about
4" x 2" compressed by about 50% in thickness. Would I have suffered a
head/brain injury? No simple way to tell without some complex math
modelling, but at least the foam did protect me from some of the impact
force. I also broke one collar bone in three places in the same fall.

Quoted message said:

Possibly you'd have escaped all injury, since it seems you hardly hit
the ground - your head might have missed the ground without a big
hat.

You can't know is the answer. So relying on this event as proof of
something (anything) is nonsense.

regards, Ian SMith
--
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|o o|
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"Peter Clinch" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

gotbent said:

"Joel" <joelw135atcomcast.net> wrote in message
news:[email hidden]...

Quoted message said:

I was riding once and I made a turn to sharp and flipped, my helmet was
cracked, imagine what would have happened to my head. I don't ride even
my trike without a helmet.

You would have broken your thumb?

Maybe, or maybe nothing much, or maybe death. Who knows?

Was there amazing head related carnage amongst cyclists before the
introduction of helmets? No. Yet ever since their introduction, although
the serious injury rates haven't moved much, they are, apparently,
responsible for saving countless lives. Doesn't really add up for hats
being lifesavers.

Do you know if the TdF or any of the cycling sports regulated groups have
collected data from the time helmets have been required in competition vs
some previous time when they weren't to look at the efficacy of protection
or lack thereof?

Quoted message said:

Oddly, places like NL and Denmark where the wearing rates are incredibly
low also have the lowest cyclist head injury rates, despite their
much-vaunted fietspads not being any proof against falling off cornering
like the above incident. Doesn't really add up for hats being lifesavers.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

--
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gotbent said:

Do you know if the TdF or any of the cycling sports regulated groups have
collected data from the time helmets have been required in competition vs
some previous time when they weren't to look at the efficacy of protection
or lack thereof?

I don't know, but I am unaware that there were particular problems, and
the only claims I have seen of sporting use underlining a need for
helmets are along the lines of "they use them in the TdF, so they must
be worth while!", which is hardly convincing and is about as sensible as
claiming helmet use (and 5 point harnesses and flame-proof suits) in the
Indy 500 means that you "obviously" need such to drive to the local
grocery store. IME there is no shortage of straw clutching to make a
case for helmet efficacy but I've yet to see even an attempt from sports
data. From any data I've yet seen, there's nothing that explains how
serious injury rates stay stubbornly unaffected by helmets no matter how
big the increase in their use is except for them not actually being much
use.

As a lad growing up in a helmet-less world I was never warned away from
my interest in cycling because of the terrible dangers of head injuries.
None of my numerous cycling peers ever managed a serious head injury,
though lots of us fell off quite a lot between us.

There are, of course, nasty head injuries in cycling but then there's
nasty head injuries amongst pedestrians (in the UK, at a slightly higher
rate per unit distance than among cyclists), so why no helmets there?
Because we know it's safe enough. Look through the haze of FUD and it
turns out cycling (A to B transport cycling at least, I'm not really
meaning downhill MTB here) is safe /enough/ too. Countries which have
always retained a cycling culture never lost sight of that, don't bother
wearing helmets nearly as much as US and UK cyclists, and don't suffer
nearly as many serious head injuries.

The sort of injuries that will seriously whack you are beyond the
specification to which cycle helmets are designed, built, and can be
expected to perform. Something like technical MTB work where you can
/expect/ to fall off and bang your head in a non-serious but remarkably
uncomfy manner is where they make a lot of sense (and where I'll wear
mine), but A to B transport cycling they make no more sense than A to B
transport walking or A to B transport driving.

And if you're just using one in case of a graze, do you wear one around
the house? Last time I drew blood from my head was on a kitchen
cupboard, and I *would* have prevented that had I been wearing a helmet.
Still don't wear a helmet to cook the dnner and unload the dishwasher
though!

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Peter Clinch said:

Look at the data for places where helmet wearing practically doubled
overnight with mandatory helmet laws: no discernible effect on serious
head injuries.

No discernible effect means not actually important.

I was going to observe that myself, until I read your post.

Evidently Bell Sports (makers of Bell and Giro helmets and notorious
mandatory-wear lobbyists) agree with us, since they no longer make
helmets meeting Snell Foundation standards!

Chalo

Peter Clinch said:

Ben Goren wrote:
<snip>

Quoted message said:

There's no reason whatsoever to doubt that I'd have at least
fractured my skull without the helmet.

So it's a safe assumption that anyone getting a concussion-worthy hit
is practically /bound/ to fracture their skull? That's a *very* big
assumption, and not one born out by one hell of a lot of falls.

Here we go again, Peter, were you present when Ben had his mishap? No?
So who is most qualified
to represent the events and possible consequences of the event, you or him?

--
Three wheels good, two wheels ok

www.catrike.co.uk

Ian Smith said:

Ben Goren said:

This past fall, I was clipped by a car that passed me. I have no memory
of the crash itself,

Quick recap - you have no idea what actually happened, but you're
certain that the helmet saved your life. Is that rational? How do you
know what effect the helmet had if you don't even know what happened?

You were there were you Ian? You must have been if you feel more
qualified than the OP to express
an opinion on the event.

Why can you not accept someones right to an opinion based on their own
experience without spouting such utter dross?

--
Three wheels good, two wheels ok

www.catrike.co.uk

Buck said:

Here we go again, Peter, were you present when Ben had his mishap? No?
So who is most qualified
to represent the events and possible consequences of the event, you or him?

Since I wasn't there and he effectively wasn't there, by his own
admission not having any recollection, *neither* of us are at all
usefully qualified, so whichever is "better" is a moot point.

I'm not making definite conclusions about what the incident tells
us though, rather pointing out simply that one is not in a useful
position to do any such thing. Can't you see 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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Buck said:

On 2007-02-04 22:12:11 +0000, Ian Smith <[email hidden]> said:

Quoted message said:

Quoted message said:

Quick recap - you have no idea what actually happened, but you're
certain that the helmet saved your life. Is that rational? How do
you know what effect the helmet had if you don't even know what happened?

Quoted message said:

You were there were you Ian? You must have been if you feel more
qualified than the OP to express an opinion on the event.

Where does he express such an opinion? All he does is question the
usefullness of the OP's stated opinion, not provide an alternative.

Quoted message said:

Why can you not accept someones right to an opinion based on their own
experience without spouting such utter dross?

Why can't you actually read what is written and work from that,
instead of jumping to the sort of ill-conceived conclusions you
rather ironically accuse others of here?

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Buck said:

Ian Smith said:

Ben Goren said:

This past fall, I was clipped by a car that passed me. I have no
memory of the crash itself,

Quick recap - you have no idea what actually happened, but you're
certain that the helmet saved your life. Is that rational? How do you
know what effect the helmet had if you don't even know what happened?

You were there were you Ian? You must have been if you feel more
qualified than the OP to express an opinion on the event.

That's not what I said.
I did not offer an opinion on the event or what would have happened
in different circumstances.
Kindly take your straw friend elsewhere if you want to argue with him.

He said he doesn't know what happened, and in the next breath he's so
sure of what happened he knows for certain what the outcome would
have been in different circumstances.

I merely asked if he thinks that is rational.

Quoted message said:

Why can you not accept someones right to an opinion based on their own
experience without spouting such utter dross?

I have no problem accepting he can have an opinion. I will not accept
without challenge the complete dross of claiming to know for certain
what would have happened with slightly different circumstances when he
doesn't actually know what happened in the circumstances that _did_
occur.

Do _you_ think it's rational to claim to know what would have
happened in different circumstances when you don't even know what
happened in the actual circumstances?

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Peter Clinch said:

Buck said:

Here we go again, Peter, were you present when Ben had his mishap? No?
So who is most qualified
to represent the events and possible consequences of the event, you or him?

Since I wasn't there and he effectively wasn't there, by his own
admission not having any recollection, *neither* of us are at all
usefully qualified, so whichever is "better" is a moot point.

Of course he was there, he had the injury and damaged lid to prove it,
he is uniquely qualified
to use the evidence at his disposal to provide an accurate depiction of events.

Quoted message said:

I'm not making definite conclusions about what the incident tells us
though, rather pointing out simply that one is not in a useful position
to do any such thing. Can't you see that?

See above.

--
Three wheels good, two wheels ok

www.catrike.co.uk

Ian Smith said:

Buck said:

Ian Smith said:

On Sun, 04 Feb 2007 14:51:55 -0700, Ben Goren <[email hidden]> wrote:

> This past fall, I was clipped by a car that passed me. I have no memory
> of the crash itself,

Quick recap - you have no idea what actually happened, but you're
certain that the helmet saved your life. Is that rational? How do you
know what effect the helmet had if you don't even know what happened?

You were there were you Ian? You must have been if you feel more
qualified than the OP to express an opinion on the event.

That's not what I said. I did not offer an opinion on the event or
what would have happened in different circumstances.
Kindly take your straw friend elsewhere if you want to argue with him.

He said he doesn't know what happened, and in the next breath he's so
sure of what happened he knows for certain what the outcome would have
been in different circumstances.

I merely asked if he thinks that is rational.

Quoted message said:

Why can you not accept someones right to an opinion based on their own
experience without spouting such utter dross?

I have no problem accepting he can have an opinion. I will not accept
without challenge the complete dross of claiming to know for certain
what would have happened with slightly different circumstances when he
doesn't actually know what happened in the circumstances that _did_
occur.

Do _you_ think it's rational to claim to know what would have happened
in different circumstances when you don't even know what happened in
the actual circumstances?

regards, Ian SMith

He does know what happened, he has the cause and effect, read his
post.
You should modify your tone.
--
Three wheels good, two wheels ok

www.catrike.co.uk

Buck said:

Ian Smith said:

Buck said:

On 2007-02-04 22:12:11 +0000, Ian Smith <[email hidden]> said:

> On Sun, 04 Feb 2007 14:51:55 -0700, Ben Goren <[email hidden]> wrote:
>
>> This past fall, I was clipped by a car that passed me. I have no memory
>> of the crash itself,
>
> Quick recap - you have no idea what actually happened, but you're
> certain that the helmet saved your life. Is that rational? How do you
> know what effect the helmet had if you don't even know what happened?

You were there were you Ian? You must have been if you feel more
qualified than the OP to express an opinion on the event.

That's not what I said. I did not offer an opinion on the event or
what would have happened in different circumstances.
Kindly take your straw friend elsewhere if you want to argue with him.

....

Quoted message said:

Quoted message said:

Do _you_ think it's rational to claim to know what would have happened
in different circumstances when you don't even know what happened in
the actual circumstances?

He does know what happened,

So, when he says "I have no memory of the crash", he actually meant "I
remember exactly what happened"? That's a novel interpretation of the
words.

Quoted message said:

You should modify your tone.

You should read what people actually post and reply to that instead of
what you've decided they might have said.

You haven't answered my question - do you think it's rational to claim
to know what would have happened in different circumstances when you
don't even know what happened in the actual circumstances?

regards, Ian SMith
--
|\ /| no .sig
|o o|
|/ \|

Buck said:

He does know what happened, he has the cause and effect, read his
post.

He knows he "went down hard". He knows he has a broken helmet.

I know that lots of people, all over the world, every day, "go down
hard" without helmets on, and yet A&E departments are not on the brink
of collapse because of the huge proliferation of fractured skulls.

I know that the specifications a helmet is built to mean it's entirely
possible a helmet can smash at energies well below those which will
fracture a skull.

I know that anecdotes claiming prevention of serious injury have
proliferated amongst helmet wearers well beyond the degree to which
helmetless riders get seriously injured.
I know that across populations there is no observable effect on serious
injuries caused by helmet wearing, so a clear possibility is that
anecdotes are not very reliable. Perhaps that's why statisticians
basically ignore them?

Thus, from what he has given us, and alternative possibilities, I
suggest that an unfractured skull is a very real possibility. Are you
saying his opinion is as good as solid fact on the fractured skull
thing? How much experience does the OP have of seeing what sort of
impacts actually fracture skulls (we don't know, but you have assumed
clearly enough, apropos of nothing, while I assume it's not known.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/

Buck said:

On 2007-02-07 17:04:11 +0000, Peter Clinch <[email hidden]> said:

Quoted message said:

Quoted message said:

Since I wasn't there and he effectively wasn't there, by his own
admission not having any recollection, *neither* of us are at all
usefully qualified, so whichever is "better" is a moot point.

Of course he was there, he had the injury and damaged lid to prove it,

He was there, but he has no recollection of exactly what happened.
Extrapolating from what he has to giving a practically /certain/ chance
of a fractured skull from the same accident without the lid is a *huge*
assumptive leap, which is what I pointed out.

The conclusion I am drawing is that any such conclusion is unsafe,
especially seen in the light of the general quality of anecdotal
evidence in this matter. Have a google through urc archives back to
sometime around 2000 and you'll find a guy with an anecdote about a
crash he was in where he was quite sure, despite not remembering the
accident, that his demolished helmet very probably saved him a fractured
skull after being dumped hard in front of a car that took him out as it
spun out of control from a collision. His name is, errrrrrr, Peter
Clinch, but subsequent hard thinking about it has led him to the
position that if he is to retain any serious degree of intellectual
honesty he cannot possibly make such an assumptive leap, or not until
there are one hell of a lot more fractured skulls coming in to A&E
departments than has ever historically been the case. It /might/ have
saved me a fractured skull, but there's a very finite possibility that
it didn't and I'm not silly enough to make calls either way that one
event or the other is as good as certain. So it's not a terribly useful
piece of evidence, but it bears /remarkable/ similarity to that
presented here.

Anecdotes are pretty useless as evidence for this sort of efficacy
reporting at the best of times, and where one can't actually remember
what happened it's hardly the "best of times". As you are well aware,
or would be if you bothered to stop and think about.

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 [email hidden] http://www.dundee.ac.uk/~pjclinch/