Warning: H*lm*t content

Peter Keller Wrote:


[snip]

Helmets are certified up to a direct blow of 20kph (very simply put
Such
a blow will not reliably crack my skull. French research seems to show
that at direct blows of more than 23kph, the polystyrofoam shatter
rather
than squashes, thereby offering no energy absorption whatsoever! No
to
keep myself as safe as possible in traffic, I am not going to rely o
a
h*lm*t, even if the stupid law forces me to wear one.

peter

--
If you are careful enough in life, nothing bad -- or
good -- will ever happen to you.

It's not about relying on a piece of foam to protect you - it doesn'
make you more or less safe in traffic. It is supposed to reduce th
incidence and severity of head injury in the event of an accident. Mos
of the literature that I've seen on the subject suggests that helmets d
exactly that.

The public policy decision of mandatory helmet law goes beyond th
scope of helmets' marginal reduction in the severity of head injur
conditional on an accident. This is because public policy must als
take the effects of helmet laws on cycling participation, publi
health, safety, as well as knock-on effects on driver and ride
behaviour.

Separating these issues from whether helmets 'do anything' is crucia
to _not_ sounding like a crackpot.

Ritc

--
ritcho

Kathy wrote:


dave wrote:

Peter Keller wrote:

On Sun, 21 Aug 2005 21:39:09 +1000, Kathy wrote:



Bleve wrote:

Helmets work.



I second that - I had no bruise or scrape or anything - not even a
headache :-)




I or you can't prove or disprove anything from this anecdote. Is very
tempting to ascribe your survival or mitigated damage to a pece of
polystyrofoam, and it is usually impossible to rerun the incident
with the
other condition, just to see how effective the helmet really would
have been --
However -- There are far more "My helmet saved my life"
stories going round than ever there were deaths and injuries before
helmets became common. And this despite the reduction in bicyclist
numbers!

Peter


Exactly what I was telling her. Although she only claims it saved her
a headache. ... will eventually arrive at a reasoned conclusion
which may or may not agree with ours


I reached a reasoned (and experienced)

Experienced?
Ive crashed pushbikes in enough ways to get respect from Hippy
Ive come off motorcycles on the high side of 200 kph.. And come off the
high side of motorcyles ( and the low side) I,ve put a rally car down a
mineshaft and destroyed a fair amount of silvertops fleet (enough to be
offered a job by taxi staffing in richmond.. who at one point averaged 2
crashes a day)

Youve fallen of 3 times that I know off and crashed I (ONE) car and that
a crummy little BMW

WHere do you get off being experienced about crashes. )



conclusion - which verified what
I had expected - the helmet stopped me giving myself a headache to go
with the sprained right thumb and torn/sprained left shoulder - which
would have REALLY made the ride back home unachievable - rather than
just unbearable...


Scientific method there.. You must be a programmer

Peter Keller Wrote:
On Mon, 22 Aug 2005 20:26:55 +1000, Claes wrote:


Peter Keller Wrote:
On Sun, 21 Aug 2005 21:39:09 +1000, Kathy wrote:



Bleve wrote:
I prefer not to entrust my safety to what is
essentially a piece of polystyrene designed to absorb th
kinetic
energy
of a fall from head height. That's all it does.


"all" it does? "I refuse to breath because all it does i
oxygenate
my

blood". Mine without doubt saved me from significant hea
injury.
I'm
mighty glad that polystyrene saved my bonce from a fall from
head-height. I landed head-first (back of head). Helmets work.

I second that - although Dave swears that my head only hit the
concrete
path AFTER I'd stopped falling, I KNOW that I hit my head - and I
for
one am VERY happy with the fact that the helmet absorbed th
impact,
not
my head - and so I had no bruise or scrape or anything - not eve
a
headache :-)

I or you can't prove or disprove anything from this anecdote. I
very
tempting to ascribe your survival or mitigated damage to a pece of
polystyrofoam, and it is usually impossible to rerun the inciden
with
the
other condition, just to see how effective the helmet really would
have been --
However --
There are far more "My helmet saved my life"
stories going round than ever there were deaths and injuries before
helmets became common. And this despite the reduction in bicyclist
numbers!

Peter

--
If you are careful enough in life, nothing bad -- or
good -- will ever happen to you.
Could it be so that people really beleive that the helmet save
their
life? I mean, if you become a veggie, may people would say life has
ended, although life has not ended, if you see what I mean.

It seems that statistics can not solve this one. How about a simple
test. You wear nothing on your head, I smack a baseball bat on your
head, just hard enough to crack you scull, then we do a test wit
your
head again, healed up and all, and smack at the same force, yo
think
you head would not crack this time?

I think my head probably would crack. However i am not volunteerin
for
the experiment!
Helmets are certified up to a direct blow of 20kph (very simply put
Such
a blow will not reliably crack my skull. French research seems to show
that at direct blows of more than 23kph, the polystyrofoam shatter
rather
than squashes, thereby offering no energy absorption whatsoever! No
to
keep myself as safe as possible in traffic, I am not going to rely o
a
h*lm*t, even if the stupid law forces me to wear one.

peter

--
If you are careful enough in life, nothing bad -- or
good -- will ever happen to you.
Hmm, I fekked up me previous post, I meant to try again, this time wit
a helmet on. I do think it would help.

What do mean with "rely on helmet even if the stupid law forces me t
wear one"? You seem to imply that when you wear a helmet you will hav
to trust it? You only trust it if you have an accident and it seem
likely that you would have as many/as few accidents with or without
helmet on. Right? So how are you relying on it? I makes no differenc
in that case, but it might save your head from some damage if you D
have an accident, which is NOT related to you wearing a helmet or not
Right

--
Claes

Claes wrote:
Peter Keller Wrote:

On Sun, 21 Aug 2005 21:39:09 +1000, Kathy wrote:



Bleve wrote:
I prefer not to entrust my safety to what is

essentially a piece of polystyrene designed to absorb the kinetic

energy

of a fall from head height. That's all it does.


"all" it does? "I refuse to breath because all it does is oxygenate

my

blood". Mine without doubt saved me from significant head injury.

I'm

mighty glad that polystyrene saved my bonce from a fall from
head-height. I landed head-first (back of head). Helmets work.


I second that - although Dave swears that my head only hit the

concrete

path AFTER I'd stopped falling, I KNOW that I hit my head - and I

for

one am VERY happy with the fact that the helmet absorbed the impact,

not

my head - and so I had no bruise or scrape or anything - not even a
headache :-)

I or you can't prove or disprove anything from this anecdote. Is very
tempting to ascribe your survival or mitigated damage to a pece of
polystyrofoam, and it is usually impossible to rerun the incident with
the
other condition, just to see how effective the helmet really would
have been --
However --
There are far more "My helmet saved my life"
stories going round than ever there were deaths and injuries before
helmets became common. And this despite the reduction in bicyclist
numbers!

Peter

--
If you are careful enough in life, nothing bad -- or
good -- will ever happen to you.

Could it be so that people really beleive that the helmet saved their
life? I mean, if you become a veggie, may people would say life has
ended, although life has not ended, if you see what I mean.

It seems that statistics can not solve this one. How about a simple
test. You wear nothing on your head, I smack a baseball bat on your
head, just hard enough to crack you scull, then we do a test with your
head again, healed up and all, and smack at the same force, you think
you head would not crack this time?


Or better. You wear the helmet. I hit you with baseball bat. If you
live.. I will buy you a new bike. With a motorcyle helmet I would do
it. What do you say; got that much faith in the things?

Not that I would really hit you with a baseball bat just to make this
point. But seriously there would be a fair chance of surviving without
wearing a helmet. I bet you wouldnt really want to put your faith in a
pushy helmet at this test. Not that thats really the point. It may
save you some abrasions. But anything more is pure optomism.

Shane Stanley wrote:
In article ,
dave wrote:


With pushy helmets there is soo little realistic evidence that they do
more than save you from scratches...


With pushy helmets there's certainly not a lot of real research. Lot's
of people have raked over a relatively small number of figures, and come
to all sorts of conclusions. But the amount of actual _research_ done
seems fairly small, if the arguments of the pro and con cases are any
guide.


Thats what I was saying. You look at anyones research and it mainly
looks pretty dodgy science. But if they made a huge difference overall
it should show up in a hurry.. And it doesnt. So maybe they make a small
positve differennce. Or they dont. Or something else is going on and
hiding a large positive difference. Or they maybe even make a negative
difference.. really hard to see that but if risk compensation is a big
factor maybe.

I,m probably not in favour of legislation even where it really makes a
difference.. Cull the stupid out I say. But where the difference
isnt absolutely clear.. the people in favour of it are the people who
want to ban mountain climbing and bushwalking. And they are people I am
not in favour off

Euan Wrote:


Then please read http://www.cyclehelmets.org/papers/c2022.pdf


Pardon my sceptisism, but what a load of HAIRY BOLLOX!!!

Just how you can base a 'paper' on a 'statistic' which can claim t
accurately measure 'People who did NOT present with head injuries' i
absolutely farcical!!!!!!!!!!!
Im surprised they didnt include 'People who were NOT abducted by Alien
due to helmet use' or 'People who rotated more in their sleep, accordin
to them...'
'Oh my God!!! The same person also didnt turn up to casualty with bowe
cancer. Quid Pro Quo wearing a helmet CURES Bowel cancer!!!!!!!!"
gimme a break. geeessshhhhh

Euan Wrote:


flyingdutch replace 'helmet' with 'safety belt'. what's the
flyingdutch difference?

One doesn't have a demonstrable impact on head injury rate, the other
does. In other words one works and is worthwhile and the othe
doesn't
and is actually detrimental (reduced number cycling means increase
risk
per cyclist).


the first sentence is the ol' 'convenient ignorance' kickin in again
Howabout we run a 'study' at Goat this Friday?
I'll thwack you over the head with a chair whilst/whilst-not wearing
helmet and we shall deduct which one injures you most

"(reduced number cycling means increased risk per cyclist)"

There are lies, lies and ... statistics. You look at em long enough an
you can justify anything. I was going and riding to school during th
period when kids HAD to wear helmets and it didnt reduce any numbers a
my school. By FAR THE BIGGEST input to stopping kids riding to schoo
was the increase in congestion and fear-of-danger-to-little-johnny
nothing to do with helmets. probably more to do with TV...

--
flyingdutch

"Claes" == Claes writes:


Claes It seems that statistics can not solve this one. How about a
Claes simple test. You wear nothing on your head, I smack a
Claes baseball bat on your head, just hard enough to crack you
Claes scull, then we do a test with your head again, healed up and
Claes all, and smack at the same force, you think you head would
Claes not crack this time?

You would have to have a very fine gradient in the velocity of the
baseball bat.

Bicycle helmets absorb kinetic energy (KE). The formula for KE is:

KE = 1/2 * M * V^2

It's tempting to think that a bicycle helmet that's rated for a 19 km/h
impact will take 19km/h off of any impact speed and make a difference.
This isn't the case.

Let's say the mass is 10kg and the velocity is 19km/h. The kinetic
energy is 1805.

Now let's take an impact at 40km/h. The kinetic energy is 8,000.

So we take away the 1805 from the 8,000 which leaves 6,195.

Re-arranging the equation a bit we can find out how much speed the
helmet's taken off the impact. The effective speed of the impact is
35.2km/h.

The higher the impact speed, the more ineffective the helmet is and it's
an exponential curve. At 60km/h the effective speed of impact is
56.9km/h. At 80km/h the effective speed of impact is 77.7km/h

I ride consistently at speeds over 35km/h. A collision at that speed
whilst wearing a helmet would make the collision speed 29.39km/h. I
don't think that's going to make a huge difference to the extent of a
head injury incurred, but that's a personal judgement.

Add in the fact that I weigh considerably more than 10kg and that makes
a helmet almost irrelevant.
--
Cheers | ~~ __@
Euan | ~~ _-\,
Melbourne, Australia | ~ (*)/ (*)

"Euan" wrote in message
...
"Claes" == Claes
writes:


Claes It seems that statistics can not solve this one. How about a
Claes simple test. You wear nothing on your head, I smack a
Claes baseball bat on your head, just hard enough to crack you
Claes scull, then we do a test with your head again, healed up and
Claes all, and smack at the same force, you think you head would
Claes not crack this time?

You would have to have a very fine gradient in the velocity of the
baseball bat.

Bicycle helmets absorb kinetic energy (KE). The formula for KE is:

KE = 1/2 * M * V^2

It's tempting to think that a bicycle helmet that's rated for a 19 km/h
impact will take 19km/h off of any impact speed and make a difference.
This isn't the case.

Let's say the mass is 10kg and the velocity is 19km/h. The kinetic
energy is 1805.

Now let's take an impact at 40km/h. The kinetic energy is 8,000.

So we take away the 1805 from the 8,000 which leaves 6,195.

Re-arranging the equation a bit we can find out how much speed the
helmet's taken off the impact. The effective speed of the impact is
35.2km/h.

The higher the impact speed, the more ineffective the helmet is and it's
an exponential curve. At 60km/h the effective speed of impact is
56.9km/h. At 80km/h the effective speed of impact is 77.7km/h

I ride consistently at speeds over 35km/h. A collision at that speed
whilst wearing a helmet would make the collision speed 29.39km/h. I
don't think that's going to make a huge difference to the extent of a
head injury incurred, but that's a personal judgement.

Add in the fact that I weigh considerably more than 10kg and that makes
a helmet almost irrelevant.
--
Cheers | ~~ __@
Euan | ~~ _-\,
Melbourne, Australia | ~ (*)/ (*)

Ooh. Here's me thinking KE=M*V

That does make a bit of difference, dunnit? I do wonder how constant the
energy dispersion of a helmet relative to speed is though. Probably not a
squared function though.

"flyingdutch" == flyingdutch writes:

flyingdutch Euan Wrote:


Then please read http://www.cyclehelmets.org/papers/c2022.pdf


flyingdutch Pardon my sceptisism, but what a load of HAIRY
flyingdutch BOLLOX!!!

flyingdutch Just how you can base a 'paper' on a 'statistic' which
flyingdutch can claim to accurately measure 'People who did NOT
flyingdutch present with head injuries' is absolutely
flyingdutch farcical!!!!!!!!!!!

I can't find the phrase ``people who did not present with head
injuries'' in the document. Could you clarify please?
--
Cheers | ~~ __@
Euan | ~~ _-\,
Melbourne, Australia | ~ (*)/ (*)

The human brain is not a vegetable. It's a highly sophisticated organ
which is highly protected by a thick skull and in-built shock
absorption. Comparing the two is like comparing apples and oranges.

He he, it was an example, nothing else, read it and apply "critica
thinking" to it.

Please read http://www.cyclehelmets.org/papers/c2022.pdf

Then come back to me and explain to me the case for helmet compulsion
when it's proved beyond all doubt that helmet compulsion discourages
cycling and therefore increases the risk per kilometer cycled because
there are less cyclists on the road.

Ehh, what that does that prove? You can not prove what would hav
happened without the helmets. Too many other variables change, and man
are not included. That report is total BS.

I have statistics from a "county" in sweden, where we do NOT have cycl
helmet laws. It shows that 40% of cycling related accidents result i
head injuries that COULD be less severe with a helmet. Apply you
critical thinking again please.

Why would a helmet have no effect? The effect of having a material tha
compresses, and absorbs some impact energy has been proved wit
motorcycle helmets, why would it not apply for a bike helmet? Pleas
tell me, I really want to know

--
Claes