published helmet research - not troll

Pete wrote:
"Steven Bornfeld" wrote

As long as this is not libertarian, and allowing that proper bicycle
maintenance and effective cycling are more important to cyclist safety,
what would your feelings be about:
1) Mandatory licensing of cyclists (as per motor vehicles)
2) Mandatory minimum age for cyclists on public streets and roads
3) Mandatory registration of bicycles and periodic bicycle inspections



This list is a perfectly good way of eliminating cycling injuries completely
within one generation.

Of course, it would also eliminate cycling in general. If you don't cycle as
a kid, it is highly unlikely you would ever do it as an adult.

Pete

Maybe. I put up with this for my car. No reason I wouldn't for my
bike. Not saying I would advocate any or all of this, but I might on
reflection. Mandatory inspection makes a lot more sense to me than
mandatory CPSC regs such as reflectorized pedals.

Steve

"Steven Bornfeld" wrote in message
...


Pete wrote:
"Steven Bornfeld" wrote

As long as this is not libertarian, and allowing that proper bicycle
maintenance and effective cycling are more important to cyclist safety,
what would your feelings be about:
1) Mandatory licensing of cyclists (as per motor vehicles)
2) Mandatory minimum age for cyclists on public streets and roads
3) Mandatory registration of bicycles and periodic bicycle inspections



This list is a perfectly good way of eliminating cycling injuries
completely
within one generation.

Of course, it would also eliminate cycling in general. If you don't
cycle as
a kid, it is highly unlikely you would ever do it as an adult.

Pete

Maybe. I put up with this for my car. No reason I wouldn't for my
bike. Not saying I would advocate any or all of this, but I might on
reflection. Mandatory inspection makes a lot more sense to me than
mandatory CPSC regs such as reflectorized pedals.


Item: Brake inspection. Do you mandate two functional brakes? One? I can
ride a no-brake fixie very well.
Item: Lights. Required? Why?
Item Registration. What price would you put on a years bike registration?
$1? $5? The same as a car? Either way, its a bad choice. Either not cost
effective, or wildly out of proportion.
Item: Licensing and minimum age. What age would this be? 16? 14? 12? By age
14 or so...if they haven't ridden yet, they arent likely to.

Motor vehicles are thusly regulated because of the enormous potential for
damage. Bikes, and other forms of transport have no such potential.

I have a house on a very short, 8 house cul-de-sac. Zero traffic, except for
residents. Rules such as this would prevent my 8 year old neighbor from
riding across the street to her friends house.

Do we license pedestrians next?

Pete
Nice troll, though.

Pete wrote:
"Steven Bornfeld" wrote in message
...


Pete wrote:

"Steven Bornfeld" wrote


As long as this is not libertarian, and allowing that proper bicycle
maintenance and effective cycling are more important to cyclist safety,
what would your feelings be about:
1) Mandatory licensing of cyclists (as per motor vehicles)
2) Mandatory minimum age for cyclists on public streets and roads
3) Mandatory registration of bicycles and periodic bicycle inspections



This list is a perfectly good way of eliminating cycling injuries

completely

within one generation.

Of course, it would also eliminate cycling in general. If you don't

cycle as

a kid, it is highly unlikely you would ever do it as an adult.

Pete

Maybe. I put up with this for my car. No reason I wouldn't for my
bike. Not saying I would advocate any or all of this, but I might on
reflection. Mandatory inspection makes a lot more sense to me than
mandatory CPSC regs such as reflectorized pedals.



Item: Brake inspection. Do you mandate two functional brakes? One? I can
ride a no-brake fixie very well.
Item: Lights. Required? Why?
Item Registration. What price would you put on a years bike registration?
$1? $5? The same as a car? Either way, its a bad choice. Either not cost
effective, or wildly out of proportion.
Item: Licensing and minimum age. What age would this be? 16? 14? 12? By age
14 or so...if they haven't ridden yet, they arent likely to.

Motor vehicles are thusly regulated because of the enormous potential for
damage. Bikes, and other forms of transport have no such potential.

I have a house on a very short, 8 house cul-de-sac. Zero traffic, except for
residents. Rules such as this would prevent my 8 year old neighbor from
riding across the street to her friends house.

Do we license pedestrians next?

Pete
Nice troll, though.

Not at all. You can make the rules as draconian as you wish, or not.
One might regulate driving on public roads, or designate certain areas
that might be exempt (like snowmobiles, for example). You may set a
reasonable age (say 10) but mandate passing a test. One could tax
bicycle components and dedicate funds for enforcement.
I'm not a legislator, but the choice shouldn't be between no regulation
and stupid over-regulation. Of course if you believe there is no safety
issue to speak of, there's no reason to speak about this at all.

Steve

"Steven Bornfeld" wrote

Not at all. You can make the rules as draconian as you wish, or not.
One might regulate driving on public roads, or designate certain areas

Public roads are public roads. That includes the 6 lane arterial and the 5
house cul-de-sac.
Do we exempt certain streets? Or only include certain streets?

that might be exempt (like snowmobiles, for example). You may set a
reasonable age (say 10) but mandate passing a test.

10 is a reasonable age? So I can't ride with my 9 year old on quiet
residential streets?

One could tax bicycle components and dedicate funds for enforcement.

They already are. Sales tax on bike parts goes into the general fund, like
everything else.

I'm not a legislator, but the choice shouldn't be between no regulation
and stupid over-regulation.

The 'regulation' is already there. Pretty much every city and state code
says cyclists *must* follow most of the same rules as motorists. Enforce as
necessary.

Of course if you believe there is no safety
issue to speak of, there's no reason to speak about this at all.

To be sure, a large number of bike-car crashes are due to the cyclist doing
something stupid. Riding at night with no lights, wrong way riding, zooming
out of a driveway.
Is giving a 10 year old a test and making her parent pay a registration fee
the answer? It doesn't seem to have helped in the other large percentage of
bike-car crashes that are due to the tested, licensed, and registered
motorist doing something stupid.

Education and enforcement is the key...not more unenforced rules.

Pete

On Sat, 19 Jun 2004 22:31:00 -0400, Steven Bornfeld
wrote:

Mandatory inspection makes a lot more sense to me than
mandatory CPSC regs such as reflectorized pedals.

Who and how many people would this help? In talking about public
policy, you've got to ask what is the benefit and what is the cost? I
see benefit for an extremely small amount of people and cost for an
extremely large number of people. So I don't understand the point of
this suggestion.

JT

On Sat, 19 Jun 2004 18:38:51 -0400, Steven Bornfeld
wrote in message
:

Let me see if I get this straight. All the studies showing a benefit
have fatal flaws; all the studies that show no benefit are well-designed.

Not necessarily.

There are, as I said, essentially two sorts of study. Small-scale
prospective studies, of which the 1989 Thompson, Rivara and Thompson
is the best-known; these show unequivocal benefit and large scale
savings in injuries. Then there are population-level studies, which
are equivocal. They show no measurable bnefit. They show lots of
confounding factors.

I have seen rebuttals of all the major pro-helmet papers. Most of
these rebuttals are valid, like the criticism of the control group in
TR&T which effectively makes the whole thing worthless. I have yet to
see any rebuttal of a population-level study. I do read everything I
can find, and I was originally strongly pro-helmet and in favour of
compulsion for children.

One of the key factors in changing my view was the fact that I had no
idea the population level studies even existed. Helmet promoters were
telling me that helmets save 85% of head injuries and 88% of brain
injuries, stated as fact, but then I found that even the original
authors had revised these estimates downwards, and that the figures
were well known to be unreliable. It's like the business of WMD: as
the lies start to be exposed, you have to question whether there is
any basis of truth at all.

Actually the real position is probably that helmets prevent most
trivial injuries and very few serious ones. There is a probably
narrow band of cases where helmets may turn a serious injury ionto a
minor injury, but risk compensation also means that there is another
band of cases where the crash would not have happened in the first
place had the rider not been wearing a helmet. So overall there are
solid reasons why, at the population level, where only serious and
fatal injuries are counted, there would be no visible effect; while at
the detail level, where all injuries are counted, some effect may be
seen.

All that, I have no problem with.

I do have a problem with helmet promotion which igniores the
distinction between different kinds of crash and different kinds of
injury. The idea that because a helmet saves a cut head it will
necessarily prevent massive brain trauma when hit by a pseeding truck
is laughable, but by using a single figure for injury reductions that
is exactly what the promoters are trying to imply.

I also have a problem with the excessive focus on helmets. In the
minds of the medical and legislative communities, wearing a helmet
seems to be viewed as the first, best thing a cyclist can do to ensure
their safety. There is no credible evidence to support that
prioritisation. The only thing which I can think of which has been
proved everywhere to omprove safety, is more people cycling. So if
you want cycling to be safer, you have to promote cycling (and good
cycling skills, obviously). Promoting helmets requires that you build
the perception of cycling as a hazardous activity, which works against
that goal.

The studies I saw cited are all retrospective studies. I believe it is
possible that somewhere a paper may have been published that confuses
percentages for percentage points. It is hard to believe this happened
multiple times in referreed journals.

There are recognisable flaws with many of the key papers. You can
find some good critiques at http://www.cyclehelmets.org and
http://www.cycle-helmets.com and other places too.

Let me be clear--I am not an expert in safety data nor in epidemiology.
But I am up to my eyeballs in newsgroup pundits (in unrelated fields)
making patently ridiculous claims about the body of evidence in fields
in which I do have expertise. It is impossible for me to evaluate
helmet data for myself, nor have I found it prudent to believe folks
such as yourself who may very well have that expertise.

OK, but some of us are not your garden-variety newsgroup pundits.
Some of those who post have actually done research. I have analysed
UK child hospital admissions returns and found that there is no
significant difference in the proportion of head injuries suffered by
road cyclists and pedestrians, despite helemt wearing rates only
around 15%. That doesn't suggest to me that cycling is especially
dangerous. I work with John Franklin, probably the UK's leading cycle
safety expert, and I've talked to the people who test helemts against
the standards. It was they who told me that modern helmets are far
weaker than those in the TR&T study, and that many helmets fil the
tests anyway.

These guys have shown me that scepticism is not a contrarian view.
That's the point. We are no anti-helemt, we are anti-FUD. Someone is
trying to sell you an expensive product; the manyufacturers can't say
it will save you if you are hit by a car because they know damn well
it won't, so they fund studies and they fund groups like Safe Kids and
they get someone else who won't get sued when you die to tell you that
helmets are a magic panacea to all cycling injuries.

One hopes that people in position of authority choose carefully in whom
they listen to when policy is made.

If only. The UK's Department of Transport currently bases its policy
on an "independent review" written by a team of people all of whom
work together, and several of whom have published papers calling for
helmet compulsion. No sceptic was included in the review body. Some
factual errors have since been removed, but it remains a dogma-driven
document written by those promoting helmets.

There are three sides, you see: pro-helmet, anti-helmet and sceptic.
Most cyclists who have read all the facts become sceptics: they make
up their own minds and think others should also be allowed to do so.
Newbies tend to be pro-helmet, until they realise that their
pro-helmet view is largely the result of not being given all the
facts. The number of anti-helemt people is very small. And I'n not
one of them. See my website if you are in any doubt of that.

That, of course, is a fundamental problem. Any agnostic who argues
with a True Believer will end up sounding like an atheist, even though
they are not.

See, I'm going to have to look up that paper. It is very, very
difficult for me to believe that NEJM would publish a paper with a flaw
that blatant.

Sure. Just as it is hard to believe that the percentage points
problem would have got past the peer review process. But what you
have to remember is that these guys are looking for helmets to work.
When I was training as an engineer i was told to guard against that.
The idea of an experiment is to test a hypothesis, not to find data to
support it. You're supposed to try to disprove, not prove, your
initial premise. In this case the researchers (funded, unless I've
been misinformed, by the Snell Insititue) had already decided on the
outcome before they started.

Anyway, if you have trouble getting a copy, let me known and I'll send
you a PDF. I can also give you John Franklin's comments on it.

The fact that head injury rates have risen by 40% in the USA in a
period when helmet use rose from 18% to 50% surely tells us something.

Are we talking about cycling head injuries, or total head injuries?

Cycling.

As does the fact that the pro-helmet British government has admitted
that it knows of no case where cyclist safety has improved with
increasing helmet use.

I'd love to hear some context.

It was a letter from the road safety minister to an MP, in response to
a question about whether the Government would be supporting a bill to
compel children to wear cycle helmets, which had been introduced as a
Private Member's Bill. There's a commentary on the process he

url:http://www.chapmancentral.co.uk/web/public.nsf/Documents/martlew_bill

In order to get the Member concerned to move the Bill, the propsers (a
singl;e-issue pressure group) provided a lot of statistics like
"28,000 cycling-related head injuries annually" (which turned out to
be 1,200), and compulsion representing "20,000 tragedies saved every
year" (which turned out to be 500 known serious injuries, almost all
sustained in crashes with motor vehicles).

I return to my earlier point: if the case were that clear-cut, why is
it necessary to exaggerate the figures?

The pressure group also got one grieving mother to travel to London to
promote the Bill, having told her that her child would have lived had
he been forced to wear a helmet (which, of course, you can't prove;
his injury sounds as if it could have been caused by rotational forces
which helmets can't mitigate). So I read the Coroner's report. He
had ridden off the footway into the path of a car because his bike had
defective brakes. Footway riding and riding a bike with defective
brakes are already offences. So why is this a case for comlsory
helemt use, rather than enforcement of existing regulations? And why
should we believe that a teenage boy already breaking two laws would
obey a third? And in any case, telling the mother that if only there
had been a law to compel helmet use her child would be alive today is
a heartless and cynical piece of manipulation.

It is certainly understandable to me that racers who'd become
accustomed to the wind in their hair would object to the "intrusion" of
the insurance companies. Certainly there had been no studies back then
demonstrating the uselessness of helmets in preventing serious injuries,
but those I spoke to (some of whom you undoubtedly know personally) were
just as opposed to mandated helmets as you are now.

That was not, in my opinion, an actuarial judgement; there was not
enough data to go on at the time. Quite why a device designed for a
crash at around 12mph should be mandated for racing is an interesting
philosophical question.

Actually in this area you have a point. It was a decision made for the
USCF by whichever insurance carrier was willing to write the liability
policy. Far be it from me to tell you their decisions are made on the
basis of good, rational data. ;-)

Just so. Actuarial data relies on long-term trends and large data
sets. In this case it looks more like a kneejerk reaction to asingle
incident. As those who follow pro racing know only too well, the
mandatory use of helmets has not stopped racing cyclists from dying of
head injuries. The numbers are in any case too small for robust
statistical comparisons to be made.

Only about 10% of cyclist injuries are to the area covered by the
helmet and many (possibly most) cyclists who die of head injury also
have other mortal injuries. Most fatal cyclist injuries are of course
sustained in crashes involving motor vehicles: it is motor traffic,
not cycling, which is dangerous.

Statistically you are right of course. But we are talking about
cycling; we might have much more to talk about were this a political or
automotive ng. But I know of several folks who have suffered head
injury, a couple of which were life-threatening (prolonged coma and
permanent neurological damage) without the benefit of motor vehicles.

Sure, but the fact remains that the risk of serious head injury is
(roughly an order of magnitude, according to my figures) higher where
a motor vehicle is involved. Although there is a risk there of
falling into the trap of the compulsion zealots (most of whom seem not
to be cyclists) and bundling all cycling together under a single
heading. That would be like considering a walk in the park and
free-climbing under a single heading. I know one guy who will never
walk again following a bike crash, it was probably caused by wheel
ejection due to his disc brakes. Some people do mad downhilling.
Others ride along traffic-free bike trails. Cycling is a broad
church.

I have crashed my bike and hit my head, and I've crashed and not hit
my head. I know two veterans who had similar crashes, the one wearing
the helmet died and the other survived, both the result of hitting
potholes in the road, no car involved. Life is one giant crapshoot,
after all. In the end, though, the evidence suggests that cycling is
not an unusually dangerous activity.

The biggest problem with helmet promotion is that it reinforces the
perception of cycling as dangeorus without teaching any of the
techniques which reduce the danger. In doing so, it actively deters
cycling, which paradoxically /increases/ risk.

Clarification please: are you talking about relative risk to the rider,
or total risk to the population?

Sound question.

An individual cyclist can reduce the risk to themselves by using good
riding techniques (e.g. Effective Cycling). "Cyclist hit by turnign
goods vehicle" is nasty, often leading to fatal crushing injuries of
the torso. The solutionis simple and obvious: don't ride up the
inside of trucks and buses. If you are going to pass in a traffic
line, do so on the outside, ensure that the driver is not signalling
before you start, be aware that they swing round corners and that the
trailer of a semi cuts in, make sure the driver can see you (if yo
can't see his mirrors, he can't see you). All of which sounds
blindingly obvious, but you'd be amazed at how many cyclists have a
lightbulb moment when you tell them this. There are lots of other
simple techniques and bits of knowledge which help cyclists coexist
more safely with motor traffic. So, the general answer is: for the
individual.

Also, risk to the individual rider is lower where more people cycle.
Cycling also brings health benefits which offset some of the external
risks imposed on the cyclist by motorists, so a regular utility
cyclist will enjoy a lifespan two years or more longer than average
(Mayer Hillman puts the benefits as outweighing the risks by 20:1).

In terms of the general population, mode switching to cycling has huge
potential benefits. Crashes involving cyclist v cyclist or cyclist v
pedestrian are very rarely fatal or even serious.

My objections to helmet compulsion are not libertarian, but
evidence-based. We have the experience of laws in Australia, New
Zealand and Canada to draw on. In no case did injury rates reduce.
In every case cycling was deterred.

As long as this is not libertarian, and allowing that proper bicycle
maintenance and effective cycling are more important to cyclist safety,
what would your feelings be about:
1) Mandatory licensing of cyclists (as per motor vehicles)
2) Mandatory minimum age for cyclists on public streets and roads
3) Mandatory registration of bicycles and periodic bicycle inspections

All of these have been suggested at various times. They all share one
of the fundamental weaknesses of helmet compulsion, in that they deter
cycling. Almost no restriction is going to affect me, riding 5,000
miles per year or more and with an investment of around $10,000 in
bikes. The rider who has an x-Mart bike and is prompted by a "get off
your ass!" promotion to try riding to the corner shop for his
newspaper will be faced with either going out and getitng a whole load
of expensive training and licenses; breaking the law; or driving
(again). You can guess which is going to win.

There are other reasons, too. For example: most adults already have a
car driver's license. For example: we don't require pedestrians or
horse-riders to be licensed. Licensing is a requirement which applies
to motor vehicles as a response to the extraordinary levels of danger
they impose on others. They have the potential to go very fast, and
they weigh a lot. In an exchange of knietic energy, the final
velocity of pedestrian plus car is indistinguishable form the velocity
of the car beforehand. Massive accelerations cause massive damage.
Bikes are small, light, and relatively slow. So there is not
sufficient concern to justify a licensing scheme. I am absolutely in
favour of voluntary schemes, and schemes run by schools and councils.

Minimum age? Well, where would you put that? My ten-year-old can
ride safely on the roads here, he has already passed Cycling
Proficiency and he's ridden day rides of 50 miles or more with groups.
He doesn't get to ride on some roads because they might require
evasive techniques he's not learned yet, and because they require too
much concentration. His friend of the same age is not allowed on the
road on his own because he has no road sense yet. Most parents should
be smart enough to realise when their child will be safe on the road,
and those who aren't will be placing their child in danger in other
ways too.

Registration and inspection? The deterrent effect, of course, plus
the fact that it would be virtually unenforceable. I would make bike
repairs free fo any local sales taxes, encourage "Dr. Bike" schemes
with free inspections at schools and community centres. I'd even have
beat cops tag bikes which are obviously unsafe. But the danger is
principally to the rider. The danger of a defective car is to those
around the driver.

It's a bit like Russian roulette. With cycling you have five empty
chambers and the gun is pointing at your head. With driving you have
six loaded guns, only one of which is pointed at you, and pull one
trigger at random.

But of course, these are unwelcome messages. When you compare child
head injury rates for road crashes you find that pedestrians and
cyclists have around the same proportion of head injuries, and
pedestrian injuries are much more numerous (the risk levels in
off-road cycling for children are an order of magnitude lower). Any
justification of cycle helmet promotion applies to a much greater
extent to walking helmets. And even more so for car occupants, whose
fatality rate from head injuries is much greater.

Another clarification please: The head injury rates for cyclists vs.
pedestrians vs. auto passengers are for 1) Mile traveled
2)total number in population 3) hour spent in activity

These are the proportions of all admissions which are due to head
injury. So, if you have a bike crash, you are not markedly more
likely to suffer head injury than if you are hit as a pedestrian.

The risk levels comparison: 10% of cycling is on road, 90% off road.
Slightly over 50% of admissions are due to road traffic crashes,
slightly under half due to crashes with no motor vehicle involved.
Allowing for a small number of simple falls in road riding, the risks
are, to a first approximation, an order of magnitude higher for road
riding.

I think that making the auto industry the focus in this discussion in
very much the same way makes it too easy to absolve ourselves of
responsibility in this issue.

The thing is, though, at the moment the entire focus is on us.
Looking at the figures, that's not going to work. Apart from anything
else, the same motor risks affect pedestrians, and the number of
pedestrians killed and injured is very much higher than the number of
cyclists (5-10 times in the UK). Of course motor drivers should not
be the sole focus of attention. But right now they are not the focus
of /any/ attention in the cycle safety debate. That is what needs ot
change.

if we wish to appear to be "doing something",
it is not enough to fault those who think helmet laws will save us; we
must have the courage (and the political clout) to do something that
WILL be meaningful.

Trust me, I am doing far more than bashing the Liddites. My point is,
really, that it is not sufficient for motorists to come along and say
it's all my own fault for not wearing a helmet when they knock me off
my bike. It's been tried by several insurers in the UK, and in each
case thus far they have failed, but that is in part due to work done
by our CTC (largest cycling club) who have set up a Cyclists' Defence
Fund to fight such cases. There is a debate to be had on cycle
safety, and the helemt issue is merely drawing attention away from it.
Actually I'm composing a letter on that issue at present:

url:http://www.chapmancentral.co.uk/web/public.nsf/Documents/IP

Anyway, I can see that you have started to question the orthodox view
on helmets, wich is a good thing. Whether you conclude that you
personally should or should not wear a helemt, I can't say; and
actually I think that's up to you anyway. I think you will probably
come to agree (if you don't already) that helmet compulsion is an
essentially facile solution, an experiment which has failed wherever
it's been tried. It is time to move on to the real issues, as
discussed above.

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

88% of helmet statistics are made up, 65% of them at Washington University

On Sat, 19 Jun 2004 23:34:30 GMT, "Shayne Wissler"
wrote in message
944Bc.71708$eu.12036@attbi_s02:

Casual observation would imply the opposite. Helmets are more slippery than
skin,

Er, not quite. That only really applies to hard shell helmets.

and they have a larger radius than the skull.

Correct. This amplifies rotational forces.

Also, the helmet is not
as tightly coupled to the head as the skin is

Incorrect. A correctly fitted helmet will not rotate on the head.

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

88% of helmet statistics are made up, 65% of them at Washington University

On Sat, 19 Jun 2004 23:43:18 GMT, "Shayne Wissler"
wrote in message
qc4Bc.71740$eu.47441@attbi_s02:

Dayum, Shane! No one ever thought of this clever insult before!

Gee, I guess when someone had thought of something before, then it must not
be worth saying, eh?

In this case it wasn't worth saying in the first place, of course...

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

88% of helmet statistics are made up, 65% of them at Washington University

John Forrest Tomlinson wrote:
On Sat, 19 Jun 2004 22:31:00 -0400, Steven Bornfeld
wrote:


Mandatory inspection makes a lot more sense to me than
mandatory CPSC regs such as reflectorized pedals.


Who and how many people would this help? In talking about public
policy, you've got to ask what is the benefit and what is the cost? I
see benefit for an extremely small amount of people and cost for an
extremely large number of people. So I don't understand the point of
this suggestion.

JT

I don't know the answer to this. One might think that self-interest
would make automobile inspections unnecessary as well--maybe you agree.
But if you don't, I do not see a fundamental difference in principle.

Steve

"Just zis Guy, you know?" wrote in message
...
On Sat, 19 Jun 2004 23:34:30 GMT, "Shayne Wissler"
wrote in message
944Bc.71708$eu.12036@attbi_s02:

Casual observation would imply the opposite. Helmets are more slippery
than
skin,

Er, not quite. That only really applies to hard shell helmets.

If you say so.

and they have a larger radius than the skull.

Correct. This amplifies rotational forces.

The rate of rotation is diminished with the larger radii. And it's the
acceleration to that rate that matters not the torque.

Also, the helmet is not
as tightly coupled to the head as the skin is

Incorrect. A correctly fitted helmet will not rotate on the head.

I wasn't talking about the helmet spinning freely here, I'm talking about a
small rotation on impact. Surely you don't fasten your helmet to your head
with epoxy?


Shayne Wissler