Helmets on GMTV

[-Lsqnot Respond]

FFS.

My wife just called me in to watch a 'report' on GMTV about cycle helmets and the wonderful news [in
the eyes of the presenter and the grieving mum] that they might soon become compulsory.

If anyone gets hacked off with the debate here and on other cycle forums, you sholud see what's
going on outside our world.

Dodgy stats [90 brain damaged children every week - surely not true] and dodgy common sense.

I am so spittingly angry. I might write more when I've relaxed a bit.

I am particularly livid on this topic because so many people have told me off since my crash for [a]
not choosing transport with 'more metal around me' and not wearing a helmet. The two are related
in that the real issue is that people shouldn't need armour of any sort.

 

[-Lsqnot Respond]

On Wed, 07 Jan 2004 08:54:50 +0000, "[Not Responding]"
<[email protected]> wrote:

>FFS.
>
>My wife just called me in to watch a 'report' on GMTV about cycle helmets and the wonderful news
>[in the eyes of the presenter and the grieving mum] that they might soon become compulsory.
>
>If anyone gets hacked off with the debate here and on other cycle forums, you sholud see what's
>going on outside our world.
>
>Dodgy stats [90 brain damaged children every week - surely not true] and dodgy common sense.
>
>I am so spittingly angry. I might write more when I've relaxed a bit.
>
>I am particularly livid on this topic because so many people have told me off since my crash for
>[a] not choosing transport with 'more metal around me' and not wearing a helmet. The two are
>related in that the real issue is that people shouldn't need armour of any sort.

A link for the gmtv view on the issue :

http://www.gmtv.co.uk/index.cfm?articleid=9418

I would phone and write and try and get a slot but can't as i'm [a] off sick and on pretty good
painkillers that seem to have sot any ability to write clearly.

Hope someone else does/

 

[Chris]

Not Responding wrote in message ...
> My wife just called me in to watch a 'report' on GMTV about cycle helmets and the wonderful news
> [in the eyes of the presenter and the grieving mum] that they might soon become compulsory.

My kids saw that, and for the first time ever they actually asked for their helmets before they went
out cycling.

Mind you we do have some steepish hills nearby where they can pick up a bit of speed.

Chris, Perranporth, Cornwall. http://www.Perranporth-Caravans.co.uk

 

[W K]

"Chris" <[email protected]> wrote in message
news:[email protected]...

> My kids saw that, and for the first time ever they actually asked for
their
> helmets before they went out cycling.
>
> Mind you we do have some steepish hills nearby where they can pick up a
bit
> of speed.

Thats one good thing about helmets. Gives you the confidence to go far faster down big hills.

Yeee-haaah!

 

[hessa]

Originally posted by -Lsqnot Respond
FFS.

I am particularly livid on this topic because so many people have told me off since my crash for [a]
not choosing transport with 'more metal around me' and not wearing a helmet. The two are related
in that the real issue is that people shouldn't need armour of any sort.

My thought are that for whats it worth of course it is a freedom of choice matter as to whether to wear a helmet but I think that it's kinda mad not wearing one. Maybe you feel that you shouldn't have to but that argument really doesn't stick, because you are going to be safer if you do. There are bad motorists out there, and they often kill other motorists as well as cyclists and pedestrians. Unfortunately there are many things in this world that should be different, children should be safe to go out without there parents, but they are not and it's a matter of reviewing the risks and taking the necessary actions to reduce them, well thats the responsible way to go. Sorry if it sounds like preaching, it is an individual choice and I do respect that but if you make the choice that you don't wear one then be aware of the risks, it's a cop out to say that things should be different because they are not and thats the way that it is.

 

[Nathaniel Porte]

"W K" <[email protected]> wrote in message
news:[email protected]...
>
> "Chris" <[email protected]> wrote in message news:EVSKb.8941$KZ5.89119936@news-
> text.cableinet.net...
>
> > My kids saw that, and for the first time ever they actually asked for
> their
> > helmets before they went out cycling.
> >
> > Mind you we do have some steepish hills nearby where they can pick up a
> bit
> > of speed.
>
> Thats one good thing about helmets. Gives you the confidence to go far faster down big hills.
>
> Yeee-haaah!
>

Bit like crumple zones and seat belts in cars....

 

[Zog The Undenia]

[Not Responding] wrote:
> On Wed, 07 Jan 2004 08:54:50 +0000, "[Not Responding]" <[email protected]> wrote:
>
>
>>FFS.
>>
>>My wife just called me in to watch a 'report' on GMTV about cycle helmets and the wonderful news
>>[in the eyes of the presenter and the grieving mum] that they might soon become compulsory.
>>
>>If anyone gets hacked off with the debate here and on other cycle forums, you sholud see what's
>>going on outside our world.
>>
>>Dodgy stats [90 brain damaged children every week - surely not true] and dodgy common sense.
>>
>>I am so spittingly angry. I might write more when I've relaxed a bit.
>>
>>I am particularly livid on this topic because so many people have told me off since my crash for
>>[a] not choosing transport with 'more metal around me' and not wearing a helmet. The two are
>>related in that the real issue is that people shouldn't need armour of any sort.
>
>
> A link for the gmtv view on the issue :
>
> http://www.gmtv.co.uk/index.cfm?articleid=9418
>
> I would phone and write and try and get a slot but can't as i'm [a] off sick and on pretty
> good painkillers that seem to have sot any ability to write clearly.
>
> Hope someone else does/

I've already e-mailed them pointing out that the immediate effect would be to drastically reduce the
numbers of child cyclists, with consequences for child obesity and traffic (as they will need to be
driven everywhere).

 

[Patrick Herring]

"[Not Responding]" <[email protected]> wrote:

| On Wed, 07 Jan 2004 08:54:50 +0000, "[Not Responding]" <[email protected]> wrote:
...
| A link for the gmtv view on the issue :
|
| http://www.gmtv.co.uk/index.cfm?articleid=9418

I particularly liked:

"For child cyclists, 90% of their accidents occur during the day."

You mean they don't have cycling accidents in their dreams?

"The most dangerous hours for cyclists are 3-6pm and 8-9am on weekdays."

No ****, Sherlock. Now, what could be causing that I wonder?

I'm beginning to suspect the only way through this is to let them have compulsion for under 16s and
then wait for the stats to roll in. It is probably true that there would be fewer deaths in absolute
terms in the short term. But it takes ages for the counter-intuitive big picture to sink in.

On another tack: does anyone know what deceleration rate causes brain damage (I have a
gruesome image of Eichmann finding this out) and how it relates to the maximum impact speed
for cycle helmets?

--
Patrick Herring, Sheffield, UK http://www.anweald.co.uk

 

[Andyp]

"Patrick Herring" <[email protected]> wrote

> "The most dangerous hours for cyclists are 3-6pm and 8-9am on weekdays."
>
> No ****, Sherlock. Now, what could be causing that I wonder?

Actually, I was pondering the very same thing after a late night trip the other day. Apart from the
rush hour, around here in the evenings there seems lately to be a lot of Citroen Saxos with big
exhausts and the like using the place as a racetrack. And then mid morning seems to be the time a
lot of truly appalling drivers of the older generation do their trips to the shops. I don't know
which is the more dangerous.

 

[Tony Raven]

Patrick Herring wrote:
>
> On another tack: does anyone know what deceleration rate causes brain damage (I have a gruesome
> image of Eichmann finding this out) and how it relates to the maximum impact speed for cycle
> helmets?

Military research indicates the human body can withstand 45 g (600mph to 0 in 1.4s!). Data from
analysing the black box recorders after Indy Car crashes though has indicated higher values are
sustainable, maybe over 100g, for short periods..

Tony

 

[W K]

"Tony Raven" <[email protected]> wrote in message
news:[email protected]...
> Patrick Herring wrote:
> >
> > On another tack: does anyone know what deceleration rate causes brain damage (I have a gruesome
> > image of Eichmann finding this out) and how it relates to the maximum impact speed for cycle
> > helmets?
>
> Military research indicates the human body can withstand 45 g (600mph
to 0
> in 1.4s!). Data from analysing the black box recorders after Indy Car
crashes
> though has indicated higher values are sustainable, maybe over 100g, for
short
> periods..

Car accidents also can give values - from the levels of dents and distortions on parts of the car
hit by body parts.

 

[Nick Kew]

In article <[email protected]>, one of infinite monkeys
at the keyboard of "Tony Raven" <[email protected]> wrote:

> Military research indicates the human body can withstand 45 g (600mph to 0 in 1.4s!).

The mmilitary have special suits. Not just whole-body padding, but filled with fluids that respond
to high-G forces and move to constrict your body momentarily so it doesn't get deformed in damaging
ways. Apparently derived from studying dragonflies, which experience very high G-forces when
flitting about.

--
Hutton: Nobody is asking why Blair was so keen to have a damaging inquiry into a minor side-issue of
going to war.

So, what has he successfully deflected media attention from?

 

[Tony Raven]

Nick Kew wrote:
> In article <[email protected]>, one of infinite monkeys at the keyboard
> of "Tony Raven" <[email protected]> wrote:
>
>> Military research indicates the human body can withstand 45 g (600mph to 0 in 1.4s!).
>
> The mmilitary have special suits. Not just whole-body padding, but filled with fluids that respond
> to high-G forces and move to constrict your body momentarily so it doesn't get deformed in
> damaging ways.

Not AFAIK. G-suits compress the lower legs to stop the blood draining from your brain in high G
turns otherwise you'd black out and crash. The downside is they make you sick as a dog unless you
are used to them. Thats all very different from the studies into just how much deceleration the
human body could stand which is important for ejector seats, crashes and in Indy Cars, when you hit
the wall. All Indy cars now have basically a short tin can on the back whose crumpling reduces G-
forces just enough to get them into safety range. You'd think a 6" can would make no difference if
you hit the wall backwards at 200mph, but it does.

Tony

 

[Nathaniel Porte]

"Tony Raven" <[email protected]> wrote in message
news:[email protected]...
> Patrick Herring wrote:
> >
> > On another tack: does anyone know what deceleration rate causes brain damage (I have a gruesome
> > image of Eichmann finding this out) and how it relates to the maximum impact speed for cycle
> > helmets?
>
> Military research indicates the human body can withstand 45 g (600mph
to 0
> in 1.4s!). Data from analysing the black box recorders after Indy Car
crashes
> though has indicated higher values are sustainable, maybe over 100g, for
short
> periods..
>

Highest G force survived is 179.8g in a British Championship F1 race at Silverstone in the 50s.
108mph to -30 in three inches. Ouch.

I believe the highest recorded where the victim remained conscious was 114g FWIW

While we're on the subject, when black box recorders where fitted to IndyCars in the 80s, they found
that where a car crashed at 200mph, the relative speed between the car and the wall was as little as
35 mph. Sobering thought, I think.

 

[W K]

"Nick Kew" <[email protected]> wrote in message
news[email protected]...
> In article <[email protected]>, one of infinite
monkeys
> at the keyboard of "Tony Raven" <[email protected]> wrote:
>
> > Military research indicates the human body can withstand 45 g (600mph
to 0
> > in 1.4s!).
>
> The mmilitary have special suits. Not just whole-body padding, but filled with fluids that respond
> to high-G forces and move to constrict your body momentarily so it doesn't get deformed in
> damaging ways. Apparently derived from studying dragonflies, which experience very high G-forces
> when flitting about.

Were you listening to that Radio 4 thing then?

They got it wrong. Nothing to do with astronauts, a lot to do with 9G turns in fighter aircraft.

(the R4 quizmaster mentioned cornering - something that doesnt happen to astronauts, and they are
lying flat, so blood is not forced into the legs).

 

[Patrick Herring]

"Tony Raven" <[email protected]> wrote:

| Patrick Herring wrote:
| >
| > On another tack: does anyone know what deceleration rate causes brain damage (I have a gruesome
| > image of Eichmann finding this out) and how it relates to the maximum impact speed for cycle
| > helmets?
|
| Military research indicates the human body can withstand 45 g (600mph to 0 in 1.4s!). Data from
| analysing the black box recorders after Indy Car crashes though has indicated higher values are
| sustainable, maybe over 100g, for short periods..

This isn't about decelerating the head though. My thought was to find a comparison between the
minimum deceleration where you'll get brain damage versus the maximum deceleration a bike helmet is
intended for. If the latter is more than the former then bike helmets can't save anyone from brain
damage i.e. the shell cracks and the polystyrene doesn't significantly reduce the deceleration.

<google, google> The best I can find, since medical papers seem not to be online, is

http://www.bcma.org/public/bc_medical_journal/BCMJ/october_2002/PVRees.asp

which says you need a minimum of 100g of deceleration, roughly, to get brain damage (it doesn't say
what kind but implies irreversible).

http://www.cyclehelmets.org/papers/c2003.pdf says that the standard is for a maximum of 300g
(12.5mph).

So, assuming the polystyrene reduces the deceleration to below 100g (could it? I've no idea), bike
helmets could prevent brain damage below 12.5mph. I suppose that's of more use than preventing cuts
and bruises. It's possible that this would include saving a life. But this is all very back-of-an-
envelope stuff [1], the 12.5mph figure keeps leaping out at me as being not the kind of speed where
"accidents" happen. My main thought is that above 12.5 mph you could still die or go zombie even
though you have no more than superficial visible injuries.

[1] and I'm not entirely confident of my reasoning.

--
Patrick Herring, Sheffield, UK http://www.anweald.co.uk

 

[Dave Larrington]

Nathaniel Porter wrote:

> Highest G force survived is 179.8g in a British Championship F1 race at Silverstone in the 50s.
> 108mph to -30 in three inches. Ouch.

1977. The late David Purley in a LEC, trying to qualify for the British GP at Silverstone.

--

Dave Larrington - http://www.legslarry.beerdrinkers.co.uk/
===========================================================
Editor - British Human Power Club Newsletter
http://www.bhpc.org.uk/
===========================================================

 

[Mark Thompson]

> | > On another tack: does anyone know what deceleration rate causes brain damage (I have a
> | > gruesome image of Eichmann finding this out) and how it relates to the maximum impact speed
> | > for cycle helmets?

> This isn't about decelerating the head though. My thought was to find a comparison between the
> minimum deceleration where you'll get brain damage versus the maximum deceleration a bike helmet
> is intended for. If the latter is more than the former then bike helmets can't save anyone from
> brain damage i.e. the shell cracks and the polystyrene doesn't significantly reduce the
> deceleration.

You're making the same mistake helmet manufacturers and everyone else did. It's not necessarily the
deceleration that is doing the damage.

W. J. Curnow, The efficacy of bicycle helmets against brain injury, Accident Analysis & Prevention,
Volume 35, Issue 2 , March 2003, Pages 287-292.

Abstract An examination is made of a meta-analysis by Attewell, Glase and McFadden which concludes
that bicycle helmets prevent serious injury, to the brain in particular, and that there is mounting
scientific evidence of this. The Australian Transport Safety Bureau (ATSB) initiated and directed
the meta-analysis of 16 observational studies dated 1987-1998. This examination concentrates on
injury to the brain and shows that the meta-analysis and its included studies take no account of
scientific knowledge of its mechanisms. Consequently, the choice of studies for the meta-analysis
and the collection, treatment and interpretation of their data lack the guidance needed to
distinguish injuries caused through fracture of the skull and by angular acceleration. It is shown
that the design of helmets reflects a discredited theory of brain injury. The conclusions are that
the meta-analysis does not provide scientific evidence that such helmets reduce serious injury to
the brain, and the Australian policy of compulsory wearing lacks a basis of verified efficacy
against brain injury.

Highlights: The testing and design of standard helmets continue to reflect the discredited theory
that linear acceleration is the dominant cause of brain injury and to neglect rotation. Ommaya et
al. (1971) therefore called for revision of the standards, to include protection against its
injurious effects, but to no avail.

2.3. Angular (rotational) acceleration Holbourn (1943) proposed a theory of brain injury that has no
role for linear acceleration as a direct cause and rejects the mechanism of coup/contre-coup.
He started from the physical properties of the brain of being about as dense and incompressible
as water and having low rigidity. Using models of the brain and skull, he deduced that linear
acceleration arising from a blow produces only small shear strains which have no injurious
effect on the brain. Forces of rotation, by contrast, produce large shear strains and cause the
brain to slide along the internal surface of the skull. Blood vessels may then be ruptured,
causing SDH. He attributed so-called contre-coup injuries to rotation. Experimental evidence in
support of Holbourn has since accumulated (Adams et al., 1982). Pudenz and Shelden (1946)
observed, using high speed cinematography on monkeys with part of their cranium replaced with
transparent material, that the brain rotated within the skull during impact and did not draw
away from it. From the 1960s, the heads of primates were subjected to controlled acceleration,
both linear and angular. Ommaya et al. (1971) reported that such experimental work supported
Holbourn's view that only skull damage and rotation of the head are important and that pure
(linear) head translation had never been demonstrated as an injury producing factor for the
brain. They dismissed a variation of the linear acceleration theory by Gross (1958), which
proposed that a blow to the head generates pressure waves, causing cavities to form at the
opposite side of the brain and injure it as they suddenly collapse. Ommaya and Gennarelli
(1974) used apparatus that produced either pure translation or rotation of monkeys' heads
through 45° without any impact and its possible confounding effects. They found that rotation
resulted in paralytic coma or traumatic unconsciousness, but translation did not.
2.4. Diffuse injury According to Henderson (1995), three out of four cases of brain injury sustained
by road accident victims fall into the diffuse type, the commonest and mildest form being
concussion. The severe form, now designated diffuse axonal injury (DAI), was first defined by
Strich and Strich). Her microscopic examination of brain tissue of patients who suffered
extreme dementia until death found few lesions visible to the naked eye, but widespread diffuse
degeneration of the white matter. She attributed it to shear strains resulting from angular
acceleration. Graham et al. (1995) noted that DAI is the commonest cause of disability after
head injury, including the vegetative state, and that it occurs mainly in road traffic
accidents. In Glasgow, 45 out of 177 patients with fatal non-missile head injury were found to
have DAI, judged to be identical to that produced in the subhuman primate by angular
acceleration ( Adams et al., 1982). In Australia, 29 out of 62 patients fatally injured in
traffic accidents had DAI of similar character ( Blumbergs et al., 1989) and the brain of a
child pedestrian who died after being struck by a car showed injuries associated with angular
acceleration ( McCaul et al., 1988). The duration of angular acceleration is also a factor, as
experiments with primates have shown. Over a short time at a high rate it mainly affects blood
vessels, leading to SDH and contusions. A lower rate and longer duration produce DAI and
traumatic coma (Adams et al., 1986).

 

[Patrick Herring]

"Mark Thompson" <[email protected] (change warm for
hot)> wrote:

| > | > On another tack: does anyone know what deceleration rate causes brain damage (I have a
| > | > gruesome image of Eichmann finding this out) and how it relates to the maximum impact speed
| > | > for cycle helmets?
|
| > This isn't about decelerating the head though. My thought was to find a comparison between the
| > minimum deceleration where you'll get brain damage versus the maximum deceleration a bike helmet
| > is intended for. If the latter is more than the former then bike helmets can't save anyone from
| > brain damage i.e. the shell cracks and the polystyrene doesn't significantly reduce the
| > deceleration.
|
| You're making the same mistake helmet manufacturers and everyone else did. It's not necessarily
| the deceleration that is doing the damage.

Sure, I should have said I know it's a lot more complicated. I was after a first approximation as to
what helmets can possibly do. An interesting line I read in googling for those figures was that
plastic shells are good for one crack only whereas many bike accident situations are characterised
by multiple contacts e.g. you hit the bonnet as you go over it then hit the road on the other side.

Certainly I've never before seen such a clear figure as "non-contact brain damage starts at 100g,
helmet shells stop at 300g", even if it is only ball-park.

I'm still wondering how it could be shown that the polystyrene could reduce the 300g to 100g.

<snip interesting reference>

--
Patrick Herring, Sheffield, UK http://www.anweald.co.uk

Eala Earendil engla beorhtast, ofer Middangaard monnum sended.

 

[Just Zis Guy]

On Sat, 10 Jan 2004 01:37:34 -0000, "Mark Thompson"
<[email protected] (change warm for hot)> wrote:
>W. J. Curnow, The efficacy of bicycle helmets against brain injury, Accident Analysis & Prevention,
> Volume 35, Issue 2 , March 2003, Pages 287-292.

Thanks, Mark, that is first class.

Guy
===
May contain traces of irony. Contents liable to settle after posting.
http://chapmancentral.demon.co.uk