Helmets

Quoted message said:

Benjamin Lewis said:

Quoted message said:

[email hidden] wrote:
> Arm or no arm, falling off a bike does not
> "very likely" mean you'll bash your brains out! Serious head injuries
> were never "very likely" no matter what.

Wrong. A mere "topple" on from a bicycle even standing still will
accelerate your head to a high enough speed that you can sustain a
fatal head injury. It's that simple.

I notice that these two statements are not mutually exclusive. "Can" is
very different from "very likely".

There are pretty objective answers to this: the average brain in the
average head will be fatally injured in an unbroken fall from six feet
to an impact with an unyielding surface. It does not mean that that
type of impact will always or even usually occur in a "topple",

Indeed. Regardless of whether your first statement is true or not, I don't
see why you're saying Frank's statement was "wrong". Falling off a bike is
*not* "very likely" to lead to serious head injuries, just as he said.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips
over, pinning you underneath. At night, the ice weasels come."
--Matt Groening

Bill Sornson said:

You should have used it twice: "A mere 'topple'...from a bicycle even
standing still /will/ (*can*) accelerate your head to a high enough speed
that you can sustain a fatal head injury."

No, the acceleration of gravity is constant and a topple "will always"
accelerate your head to the same speed in the six feet to the
ground(disregarding unimportant variations in ambient air pressure and
head weight), hence the use of the word "will"; because of other
variables it "will not always" result in a fatal head injury, hence the
use of the word "can".

Quoted message said:

Bill Sornson said:

You should have used it twice: "A mere 'topple'...from a bicycle
even standing still /will/ (*can*) accelerate your head to a high
enough speed that you can sustain a fatal head injury."

No, the acceleration of gravity is constant and a topple "will always"
accelerate your head to the same speed in the six feet to the
ground(disregarding unimportant variations in ambient air pressure and
head weight), hence the use of the word "will"; because of other
variables it "will not always" result in a fatal head injury, hence
the use of the word "can".

Perhaps for a crash-test dummy, but human beings tend to protect their heads
with hands, arms, neck muscles, etc. -- the latter of which /can/ decrease
said acceleration to less than fatal limits.

Minor distinction, admittedly...

BS

yk said:

The price range from $10 - $200. What are the differences ? Are
expensive helmets safer or more aero-dynamically designed ? What to look
for besides fit and color ?

Opinions only:

Cheaper helmets, from what I have seen, appear to have more foam in
them. More expensive helmets have more open spaces and fancier
sculpting. It has been stated by others that the fancier, more
expensive helmets have been shown to be just barely able to pass the
impact tests in the labs, while the cheaper ones pass with a greater
margin, presumably due to having more foam. I do not know if this is
the case in fact.

As far as the rest of it is concerned, there is no doubt in my mind
that the principle functional differences between the expensive
helmets and the cheap ones are insufficient to explain the price
gradient. In my opinion, a $200 helmet has that price tag because
there is a perception in the helmet industry that there is a market
for a $200 helmet. Everything done to justify that price in the
buyer's eye is, in my estimation, purely a matter of marketing hype.

(I will note, however, that if you ride in a sweltering climate like
mine, the difference in ventilation between a $25 helmet and a $45
helmet may be worth the expense. Beyond that point, I personally
can't see enough of a difference to merit more expense...and I paid $5
each for the last two that I bought, both from Goodwill, apparently
unused.)
--
Typoes are a feature, not a bug.
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Art Harris said:

Alex Rodriguez said:

ANSI or SNELL sticker is important.

Alex, I see this all the time (especially on ride event applications).
Guess what? If your helmet is less than 10 years old, it is NOT ANSI
certified. And it's there's only a very slim chance it's SNELL
certified.

Most helmets sold in the US are CPSC certified.

See:
http://www.bhsi.org/standard.htm

IIANM, they aren't certified by the CPSC, but rather are certified by
the manufacturer as meeting CPSC requirements. US government agencies
are notorious for coming up with a standard, requiring that it be met,
and then not providing the testing themselves.
--
Typoes are a feature, not a bug.
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In article
<[email hidden]>,

Quoted message said:

Bill Sornson said:

You should have used it twice: "A mere 'topple'...from a bicycle even
standing still /will/ (*can*) accelerate your head to a high enough speed
that you can sustain a fatal head injury."

No, the acceleration of gravity is constant and a topple "will always"
accelerate your head to the same speed in the six feet to the
ground(disregarding unimportant variations in ambient air pressure and
head weight), hence the use of the word "will"; because of other
variables it "will not always" result in a fatal head injury, hence the
use of the word "can".

Get the physics correct. In free fall in a uniform gravitational
field the speed parallel to the field of the center of mass
increases linearly with respect to time; increases linearly with
respect to the square root of the distance traversed parallel to
the field. The kinetic energy increases linearly with respect to
the distance traversed.

The center of mass is never located in the region of the cranium.
Add angular momentum to a human body in free fall and movements of
the body itself and the acceleration of the cranium when the body
meets the ground varies widely.

No cans, no ifs. Categorical statements. Arguments from
experiments dropping melons in helmets are laughable.

When the cranium meets the pavement before any other portion of
the body serious injury ensues, helmet or no helmet, regardless of
the starting altitude; as the body follows torque on the cervical
vertebrae can fracture them, damage the brain stem, injure the
spinal cord, or swirl the brain in the brain pan like jelly in a
bowl. The best anyone should expect from a helmet is protection
from scalp laceration.

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.
Would a helmet have saved her life?

--
Michael Press

In article <[email hidden]>, [email hidden]

Quoted message said:

yk said:

The price range from $10 - $200. What are the differences ? Are
expensive helmets safer or more aero-dynamically designed ? What to look
for besides fit and color ? TIA

Fit is high on the list. If you don't like it, you won't wear it, it
won't be there when, not if, you need it. Christopher Reeves became a
paraplegic from a fall from a horse. Yes he was higher but dirt is
softer than asphalt.

What injuries did Mr. Reeve (note spelling) sustain in the fall?
How did the impact cause the injuries? Was he wearing a helmet
that horsemen wear?

--
Michael Press

In article <[email hidden]>,

E Willson said:

yk said:

The price range from $10 - $200. What are the differences ? Are
expensive helmets safer or more aero-dynamically designed ? What to look
for besides fit and color ? TIA

As far as I know, all helmets sold in the US meet basic safety standards

As far as you know.

Quoted message said:

defined by the consumer protection agency. I believe the standard is Z90

You believe.

Quoted message said:

(IIRC), and the helmet liner is marked accordingly. Moreover there used
to be a more stringent standard used by the SNELL institute. Helmets
with SNELL ratings used to be more safe (for penetration) than helmets
that just met the Consumer protection standards. I am not sure if SNELL

You are not sure.

Quoted message said:

still exists, but I would suggest that you look for a helmet that has a
SNELL rating if you are looking for the ultimate in safety. I would
appreciate comments from anyone who knows the current situation, because
I am not sure of it.

No, you are not. Do your own research.

--
Michael Press

In article
<[email hidden]>,

Quoted message said:

Eric Hill said:

E Willson said:

I am not sure if SNELL
still exists, but I would suggest that you look for a helmet that has a
SNELL rating if you are looking for the ultimate in safety. I would
appreciate comments from anyone who knows the current situation, because
I am not sure of it.

The Snell rating still exists, in that any manufacturer who has a
helmet that meets Snell requirements, and who wants to pay to have it
certified by Snell, can do so. However, manufacturers seem to have
decided en masse that it's not worth paying for that certification.
The US law requires CPSC certification, and they're happy enough with
that.

And I wouldn't call Snell " the ultimate in safety." Snell is just
slightly more stringent than CPSC. (CPSC requires a 2 meter drop;
Snell a 2.2 meter drop.) The impact speeds are very nearly equal.

The kinetic energy is 1.1 times as great for the 2.2 m drop as the
2.0 m drop

[...]

--
Michael Press

Quoted message said:

Quoted message said:

:-) So a 50% error doesn't matter? You're being awfully charitable
toward yourself!

4' ot 6', they're both within the design limits for which a helmet is
designed to protect a head during a fall. Arguing the distance between
your head and the pavement when you're sitting on a bicycle is
completely irrelevant UNLESS YOU ARE GOING TO ALSO MAKE THE POINT THAT
THE HEIGHT IS OUTSIDE THE LIMIT FOR WHICH THE HELMET IS DESIGNED TO
PROVIDE PROTECTION!

Well, again: General population statistics show there has not been any
decrease in rates of serious bike head injuries since helmet use has
soared. Such injuries have always been rare, but they're no more rare
now that helmets are so common.

_Something_ must be responsible for this failure. We can discuss
what's responsible - but one obvious one is that helmets, designed and
tested for disembodied heads falling six feet, are simply not up to the
task.

Again, don't misunderstand me. I'm not calling for thicker, heavier
helmets. The data I've found shows that cycling is adequately safe
without a helmet. But people need to get realistic about the observed
effects (or lack of benefits) of helmets. The idea that they are
miraculous life-savers is
clearly wrong.

Quoted message said:

Quoted message said:

Arm or no arm, falling off a bike does not
"very likely" mean you'll bash your brains out! Serious head injuries
were never "very likely" no matter what.

Wrong. A mere "topple" on from a bicycle even standing still will
accelerate your head to a high enough speed that you can sustain a
fatal head injury. It's that simple.

Would you please re-read and note the words "very likely"? Those were
the words you originally used, and they are wrong! It's NOT very
likely to happen as you describe. As evidence, we know that people
have been falling off bikes since the 1890s with very, very few
incidents such as the one you're describing.

(You must have learned to ride after 1975, and had protective parents
who made you wear a helmet while learning. Those of us who are older,
or who otherwise rode without helmets, know that head injuries were
never a serious concern.)

Quoted message said:

Quoted message said:

Certainly, there is no justification for thinking a helmet
certified only to protect a decapitated headform at only 14 mph will
suffice for any large percentage of the impacts.

I said something along the lines of, "it will protect your upper brain
tissue while the rest of your body (including brain stem) gets beat to
hell". Again, arguing with me where I agreed with you three posts back.

We disagree on how much, or whether, it will protect "your upper brain
tissue." Again, the record is not good. All those helmets appeared on
bicyclists heads, and head injuries did not drop. The helmets are
designed for very low-energy impacts. Why do you think it's impossible
that these facts are related?

Quoted message said:

Quoted message said:

"A Bicycling Mystery: Head Injuries Piling Up." [Despite greatly
increased helmet use, that is.] New York Times, July 29, 2001.
http://www.cyclehelmets.org/1028.html

It says, "No one is very sure, but safety experts stress that while
helmets do not prevent accidents from happening, they are extremely
effective at reducing the severity of head injuries when they do occur.
Almost no one suggests that riders should stop wearing helmets, which
researchers have found can reduce the severity of brain injuries by as
much as 88 percent."

"'Bicycle helmet technology is the best we have for protecting the
brain,' Dr. Kelly said. 'The helmets serve the function of an air
bag.'"

"But the most effective way to reduce severe head injuries may be to
decrease the number of accidents in the first place."

Nothing in that article suggests that helments don't provide protection
from head injuries.

???

The fact that helmet use rose tremendously, but head injuries did not
reduce? That doesn't suggest that helmets don't provide protection?

Perhaps you didn't notice the link to the actual data? Here it is:
http://www.cyclehelmets.org/1041.html

To quote from the footnotes of that data table: "The proportions of
head injuries did not change over the period despite helmet use in the
USA ncreasing from 18% of cyclists in 1991 to 50% in 2000. However,
cycle use during the period fell by 21%. Thus those who continued to
cycle were 40% more likely to suffer head injury by 2001 than in 1991."

Now, personally, I wouldn't be surprised if some of numbers in the
footnotes contain some error. I don't have high confidence in the 18%,
the 50% or the 21% - but whatever the exact numbers, those figures do
describe the trends. And with those trends, it's hard to see evidence
that all those helmets are protecting heads.

(I'm sure you won't complain about inaccurate numbers anyway, since you
believe your own 4' guess is close enough to 6'! ;-)

Quoted message said:

Quoted message said:

Hmm. Well, one of the most common serious car-bike collisions is the
left hook: car turns left into cyclist. Typical closing speed perhaps
35 mph. Do you think the impact with the cyclist will usually be
below 14 mph?

No, and if your head impacts the car, you will be in trouble. But, if
what happens is that you get knocked away from the car, when you hit
the ground the speed vector in the direction of the ground will be <
14mph, and your head will be protected while the "rest of your body is
beat to hell".

OK, I give. You are apparently unable to understand that a
multi-jointed body will behave differently than a single concentrated
mass, and you can't understand that the energy input by the striking
automobile can cause much higher speeds than gravity.

It's OK. Everyone has their limitations.

Quoted message said:

Quoted message said:

Nobody suggested that "slide out" doesn't happen. In fact, I take
great comfort in the fact that it's _always_ happened, yet it's never
caused any significant number of serious head injuries.

Brain injuries are about the only way to die from a "slide out".

Fine. Provide me with a few dozen incidents where people died when
their bikes slid out. Feel free to dig back into pre-helmet days, if
that helps.

I contend that such a fatality has always been vanishingly rare. Prove
me wrong.

Quoted message said:

Quoted message said:

Cyclists make up less than 1% of the head injury fatalities in America.

That is a meaningless statistic, so ridiculous that I am not going to
spend the time picking it apart in the many ways it could be done.

Need I say your rebuttal is not impressive?

Quoted message said:

Quoted message said:

This has _always_ been the case. The "bashing of brains" that you
fear was never an issue UNTIL Bell had a new product that needed to be
sold.

My memory of it was that it was recognized that the leather hairnet did
not provide any significant protection, and people wanted more. I knew
racers that had had concussions, they were scared, and they wanted real
protection.

To explain my position: I believe the relationship between bicycle
racing and ordinary road riding is the same as the relationsip between
NASCAR and driving out for groceries.

But having said that, road racers rarely wore leather hairnets. They
were seen almost exclusively on trackies and crit riders. Before the
hype and hysteria, even road racing was considered reasonably safe.

Quoted message said:

Quoted message said:

And it's certainly being sold! We now have an entire generation of
people who have been taught to link "bicycle" and "serious head injury"
without ever examining the data. We now have avid cyclists who mock
anyone who chooses to ride without the hat they prefer.

If you don't personally understand the relationship between head injury
and bicycling, you either don't ride enough, or you and your
acquaintances have been very, very lucky.

Good grief! I've ridden as an enthusiastic adult since 1972. I've
held many offices (including president) of a large club. I've commuted
by bike since 1977 and have done extensive touring. And I've spent
years studying bike safety data. Why do you think you know more than
I?

Let me repeat:

Quoted message said:

Quoted message said:

Here's some reading for you, complete with citations.

http://www.bicyclinglife.com/SafetySkills/SafetyQuiz.htm

Bicycling is NOT very dangerous. It does us no good to pretend it is.

I didn't say it was. But don't pretend that this cite is suggesting
that bicycling is so safe that you don't need to wear a helmet.

Talk to me about data. Use numbers. Read that article, read the
answers to the questions, and explain to me why cycling is so dangerous
that you need to wear a helmet.

Be specific! So far, you've been hand waving and speaking imprecisely.
Get precise. Use numbers.

Quoted message said:

This is the crux of the matter: there are many types of injuries that
you can have on a bike, from the bruise I have on my leg right now from
a little mtbing last weekend, to road rash, to broken bones. But,
because, of the fact that cycling is a relatively safe activity, there
are very few types of injuries that are likely to be fatal. Like a
said, a mere "topple" at a standstill is all it takes to accelerate
your brain to a speed high enough to scramble it against the inside of
your skull, so a helmet provides protection against the type of injury
that is most likely to be fatal to a bicyclist.

Get specific. Tell us how frequent that type of injury is. Tell us
how many cyclists die that way in a year. Tell us how many die that
way per hour. Prove, using numbers, that you're not fixating on some
remote possibility placed in your mind by an advertisement, or by some
mindless safety blurb.

Give us numbers. And no more of your "50% error doesn't matter"
nonsense. Give us reliable numbers, with sources. In that article,
that's what I've done.

- Frank Krygowski

Michael Press said:

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.

Ouch, scary. I had a similar experience about a year ago, but I caught
most of the impact on my shoulder instead of my head. My shoulder still
bothers me. I got a nasty bump on my head as well, but that healed in a
day or two.

Come to think of it, the *only* times I've hit my head on anything were
times when I was not riding a bicycle.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips
over, pinning you underneath. At night, the ice weasels come."
--Matt Groening

Michael Press said:

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.
Would a helmet have saved her life?

Maybe, maybe not.

What's certain though is that if she was instead riding a bicycle at
the time, the Helmet Nazis would have said that she deserved to die
unassisted.

They're very, very concerned about other people, you see.

SNELL died in the 60's from a race car crash in which his helmet
failed, spliting the shell. His wife established the standard against
which manufacturer's could be held liable in the future.

The research on low speed impact, ie. cycling, is that *rebound* does
more damage and disability upon blunt force trauma.

Designs, good ones, use deformation compliant foams which ended the
popularity of the SkidLid type helmets in the 70's. Newer designs
employ pointy glancing blow radii to avoid dead-on blunt force impacts.
The logic being far superior to have survived w/neck injury than
brainstem damage.

Quoted message said:

SNELL died in the 60's from a race car crash in which his helmet
failed, spliting the shell. His wife established the standard against
which manufacturer's could be held liable in the future.

The research on low speed impact, ie. cycling, is that *rebound* does
more damage and disability upon blunt force trauma.

Designs, good ones, use deformation compliant foams which ended the
popularity of the SkidLid type helmets in the 70's.

Hmm. While I don't recall all the details, ISTM that Skid-Lid was done
under by the first Snell standard - which was set at a level that the
Bell Biker, already in production, could pass, but the Skid-Lid could
not.

Of course, Bell had a very close relationship with Snell, and Skid-Lid
did not. But I'm sure that had _nothing_ to do with the standard being
set at that precise level!

I was at a few bike conventions at that time. For a while, Skid-Lid
had sales booths showing letters of testimony from its "satisfied
customers," the now standard "My helmet saved my life!!!!" tales. I
recall one that came with an illustration of a cyclist going forward
over the bars and landing on the top of his Skid-Lid protected head.

Of course, in our enlightened times, we know that tale must have been
inaccurate. A below-standard helmet couldn't _possibly_ have saved his
life!

But if it happens with a slightly more protective modern helmet, it's
absolute proof the helmet saved a life!

;-)

- Frank Krygowski

Michael Press said:

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.
Would a helmet have saved her life?

[censored], my niece died in a car accident from a brain stem injury. Go
back and read my ealier posts in this thread.

Darwin at work! Too bad you escaped the bloody clutches of evolution.
Social (in)security won't save you.

<[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Michael Press said:

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.
Would a helmet have saved her life?

[censored], my niece died in a car accident from a brain stem injury. Go
back and read my ealier posts in this thread.

In article
<[email hidden]>,

Quoted message said:

Michael Press said:

A young woman of my acquaintance, after a session in dance class,
dehydrated and weak from self-induce hunger, was talking to her
friends, fainted, and fell to the ground. Her brain swelled up
forcing the brain stem through the foramen magnum and she died.
Would a helmet have saved her life?

[censored], my niece died in a car accident from a brain stem injury. Go
back and read my ealier posts in this thread.

Tetchy. Reply to the rest of the posting that you excised without
comment; you could go for the full out cerebral event. Sadly, your
helmet will not help you there.

--
Michael Press