Helmets

gotbent wrote:
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 http://www.dundee.ac.uk/~pjclinch/

Roger Zoul wrote:
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 wrote:
wrote:

Ben Goren wrote:

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
. ..

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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On Mon, 05 Feb 2007 07:24:10 -0500, Joel joelw135atcomcast.net wrote:

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|
|/ \|

gotbent wrote:
"Joel" joelw135atcomcast.net wrote in message
. ..
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 http://www.dundee.ac.uk/~pjclinch/

"Ian Smith" wrote in message
...
On Mon, 05 Feb 2007 07:24:10 -0500, Joel joelw135atcomcast.net wrote:

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.

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
--
|\ /| no .sig
|o o|
|/ \|



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"Peter Clinch" wrote in message
...
gotbent wrote:
"Joel" joelw135atcomcast.net wrote in message
. ..
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?

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 http://www.dundee.ac.uk/~pjclinch/



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gotbent wrote:

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 http://www.dundee.ac.uk/~pjclinch/

Peter Clinch wrote:

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