Re: Helmet efficacy test

On 3/27/2025 8:11 AM, Zen Cycle wrote:

On 3/26/2025 11:28 PM, Frank Krygowski wrote:

On 3/26/2025 3:57 PM, Zen Cycle wrote:

On 3/26/2025 11:47 AM, Frank Krygowski wrote:

>

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Trouble is, the protection from a bike helmet is far, far less
than people are led to believe. Look up the standardization test.

>
"led to believe" by what metric? I've never seen any literature
claiming a helmet _prevents_ serious head trauma.

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WHAT???

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No helmet manufacturer or helmet advocacy group claims helmets
_prevent_ serious head trauma. They _can_ reduce severity, not
prevent it.

>
Seems to me you're focusing on the difference between "_always_
prevents" (which was never stated by anyone) and "can reduce severity."

 
Yes, I am.

The latter is more honest, but is NOT how helmets are promoted.

 
So you're saying helmets are promoted as preventing serious head trauma,
yet your only "evidence" is:
 

Try googling "Do bike helmets prevent serious head trauma?" After
reading AI's "Yes" try follow the resulting links.
>
And logically, if a helmet did prevent serious head trauma in one out
of ten cases, that would justify a "Yes" answer. In those cases a
helmet would have done what was asked.

 
Yet there is no published literature from any manufacturer or advocacy
group which supports your claim 'thats how helmets are promoted'. an AI
answer does not qualify as marketing literature.

>
I don't have a stock of marketing literature, but I suppose we can both
search online. There's this:
https://sonomasaferoutes.org/sites/default/files/lesson_7.pdf  that
states "Why Are Helmets Important? (10 minutes)
• Ask students to articulate why wearing helmets is important (because
they protect against brain injury, disability, and death). Share that
helmet use has been estimated to reduce brain injury risk by 85 percent."
>
So "they protect against brain injury, disability, and death" (with the
never corroborated "85%" that's been disallowed in U.S. government
publications). Perhaps you'll now say "That's not _exactly_ the same
wording?"
>

Well, since the helmet certification standard was established
(essentially less than 300gs linear deceleration in a 14 mph
impact), it became known that linear deceleration was far less of
a problem than rotational acceleration. Twisting the head and
brain caused far more brain injury than smacking them. But a
helmet protrudes at least an inch from the head, providing a
longer lever arm for glancing blows, potentially worsening
rotational acceleration. (Note that a bare head's slippery hair
and very loose scalp are probably evolutionary tricks to reduce
that hazard. The helmet makes those ineffective.)

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a specious argument with no scientific substantiation.

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What part did you not understand?

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I understood all of it. What I'm stating is that you have no data to
support the that helmets "provide a longer lever arm and thus can
cause more injury" claim. Every study I've link states the exact
opposite.

>
Well, I suppose the "thus" is not totally proven. I don't see how you
can claim they do not provide a longer lever arm for glancing blows.

 
I didn't. I wrote that " you have no data to support the that helmets
"provide a longer lever arm and thus can cause more injury" claim. Every
study I've link states the exact opposite."

>
I don't see you've linked any studies that specifically address the
lever arm! And I'll note a parallel between your previous objection on a
related issue, and my statement:
>
You put high value on the word "can" by saying "... They _can_ reduce
severity..." to excuse the countless times they do not. Yet you're
ignoring my statement where I'll emphasize: "... a longer lever arm and
thus CAN cause more injury."
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We're both discussing possibilities, not definite 100% effects, aren't we?
>
>

 

 A helmet absolutely is larger than the head. The radius upon which a
glancing force acts on a helmet is certainly larger than the radius on
a bare head. And BTW, that means that a certain number of misses must
be converted to hits. I hope that's obvious to you.

 
In terms of physics it's a logical path, but you have to purposely
ignore that are no studies done which show the added leverage of the
helmet causes more injuries than an beare head,...

>
Of course there are no studies on that detailed point. How on earth
would such a study be done? By testing a helmet with and without a
radius larger than a bare head?
>

In any case, _something_ seems to be causing a correlation between
rising helmet use and rising cyclist concussions. If it's not the
factors I speculated on, I'd be interested in hearing your theories.
>
See https://www.cbsnews.com/boston/news/i-team-concussions-on-the-
rise- among-cyclists/
>
https://www.slatervecchio.com/blog/bike-helmets-dont-protect-against-
concussions/
>
https://www.cbc.ca/news/health/bike-helmets-should-address-concussion-
risk-scientists-say-1.1367454
>

 
wow...ok, first off, you're again stuck in the past. All three of those
are over 11 years old.

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It's still the same universe, Zen.
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Secondly, you missed one important statistic, as

stated in
 
"Traffic-related bike fatalities decreased despite the sharp increase of
cyclists on the road.....Fatalities were down, but brain injuries were up".
 
More people wearing cycling helmets means less fatal head trauma. The
result is more _non_ fatal head trauma.

>
Look at the numbers, please. They're comparing 1997 to 2011 (in the same
old universe!).  Wiki says 1997 had 814 bike fatalities. 2011 had 682
(one of the lowest counts ever).  That difference of 132 can't possibly
be enough to explain this: “Between 1997 and 2011 the number of
bike-related concussions suffered annually by American riders increased
by 67%, from 9,327 to 15,546”?  You've got at least 6000 concussions you
haven't explained.