Warning: H*lm*t content

This is the thing about helmets, you have an accident and see the damage
done to the helmet. ``Oh thank goodness I was wearing a helmet, that
impact would have left me with brain damage.'' That's a very unlikely
scenario. People have been falling on their bonce since the beginning
of time and it is the minority of those cases which result in brain
injury.

It's not actually, it's only recently that humans have been
traveling at an elevated height along concrete surfaces. A fall onto
a natural surface (grass, dirt etc) is usually fine. A fall onto
an unyielding surface is not to kind to our relatively fragile
heads.

And, importantly, it's only recently that we've been moving at greater than
running speed. Hit the ground at 20kph and you're okelydokely. Hit the
ground at 40kph and you're much more likely to break something important.
Not always of course, but doubling impact speed is always going to skew your
results more than a touch.

David Trudgett wrote:

If a person adheres to a religion[*]
[*] And yes, +everyone+ adheres to a religion, even "atheists".

Of course they do. Not believing in God is a religion, just as not believing
in the Tooth Fairy is a religion.

Theo
Avowed Atoothfairianist.

Resound wrote:

And, importantly, it's only recently that we've been moving at
greater than running speed. Hit the ground at 20kph and you're
okelydokely. Hit the ground at 40kph and you're much more likely to
break something important. Not always of course, but doubling impact
speed is always going to skew your results more than a touch.

Err, if you fall off your bike you will hit the ground at approx 20km/h
regardless of the speed at which you are travelling. This is the design spec
of bike helmets. Should you have a horizontal velocity of 40 km/h you will
still hit the ground at 20km/h. However, should you hit a kerb or a post or
another vehicle, don't expect your helmet to be of much benefit.

Theo

"Theo Bekkers" wrote in message
...
Resound wrote:

And, importantly, it's only recently that we've been moving at
greater than running speed. Hit the ground at 20kph and you're
okelydokely. Hit the ground at 40kph and you're much more likely to
break something important. Not always of course, but doubling impact
speed is always going to skew your results more than a touch.

Err, if you fall off your bike you will hit the ground at approx 20km/h
regardless of the speed at which you are travelling. This is the design
spec of bike helmets. Should you have a horizontal velocity of 40 km/h you
will still hit the ground at 20km/h. However, should you hit a kerb or a
post or another vehicle, don't expect your helmet to be of much benefit.

Theo


So completely irrespective of the speed at which you are travelling, you'll
hit the ground at the same speed? Why do motorcyclists wear leathers then?

On Mon, 22 Aug 2005 13:52:37 +1000, David Trudgett wrote:

Religion *is* life, you know.

Really, how come I've managed to survive this long without it then?

On Mon, 22 Aug 2005 11:31:28 +0800, Theo Bekkers wrote:

As a kid, I did most of my falling off bicycles on brick or cobblrstone
surfaces, and, like Euan, I'm not a vegatable either.

Didn't do much for your spelling though

Graeme (a few helmetless knocks to my head too many)

Graeme Dods wrote:
On Mon, 22 Aug 2005 11:31:28 +0800, Theo Bekkers wrote:

As a kid, I did most of my falling off bicycles on brick or
cobblrstone surfaces, and, like Euan, I'm not a vegatable either.

Didn't do much for your spelling though

Graeme (a few helmetless knocks to my head too many)

Hehe, I think my e key is too close to my r key. Didn't do too well with
'vegatables' though. Spent the whole weekend running fencing wire. Seriously
upsets your typing capabilities.

My other excuse is my new wireless keyboard. It leaves out or doubles up on
letters as is sees fit.

Theo :-).

Resound wrote:
"Theo Bekkers" wrote

Err, if you fall off your bike you will hit the ground at approx
20km/h regardless of the speed at which you are travelling.

So completely irrespective of the speed at which you are travelling,
you'll hit the ground at the same speed? Why do motorcyclists wear
leathers then?

Umm, yes, the velocity at which you hit the ground is dependent on the
height from which you fell. Your horizontal velocity will determine how far
you slide and how much skin you lose from abrasion. Hence the leathers.

Theo

Euan wrote:
... Dr Dorothy Robinson's concern, instead, is bicycle safety. She has
just published a study in the Health Promotion Journal of Australia that
is likely to send shock waves through Australian cycling communities
with its claim that mandatory bicycle helmet laws increase rather than
decrease the likelihood of injuries to cyclists.

http://melbourne.citysearch.com.au/profile?id=53571

Personally I'd still use a helmet in winter 'cause it's a handy place to
put lights :-) Summer I'd leave the lid behind and wear a sun hat.
--
Cheers | ~~ __@
Euan | ~~ _-\,
Melbourne, Australia | ~ (*)/ (*)

Maybe the annual research report was due and someone was low on
publications

"Theo Bekkers" wrote in message
...
Resound wrote:
"Theo Bekkers" wrote

Err, if you fall off your bike you will hit the ground at approx
20km/h regardless of the speed at which you are travelling.

So completely irrespective of the speed at which you are travelling,
you'll hit the ground at the same speed? Why do motorcyclists wear
leathers then?

Umm, yes, the velocity at which you hit the ground is dependent on the
height from which you fell. Your horizontal velocity will determine how
far you slide and how much skin you lose from abrasion. Hence the
leathers.

Theo

Ok, that's valid, assuming a dead flat surface wherever you ride a
bike...you know, no gutters, rocks, logs, parked cars etc.