How to protect your brain by not wearing a helmet

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
Steady rider
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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 26 Aug 2020, 7:34pm

The paper. 'Effects of bicycle helmet wearing on accident and injury rates' page 12 details;

Research has reported cyclists incurring up to 10g forces due to hitting pot holes and lower g forces from road humps, manholes covers and situations where the road/path is not smooth and even. A recent article details g forces from slow cycling speeds incurring up to 6g acceleration forces . A lightweight helmet at 0.25 kg incurring a 4g acceleration would involve a force of about 10N or 2.2 lbs force imperial. In general, helmet use results in extra forces per typical hour cycled and, on some occasions, they may add to problems in maintaining balance. Therefore, the increased "other" rate, mainly falls, is what could be expected from helmet use.

Zang, K.; Shen, J.; Huang, H.; Wan, M.; Shi, J. Assessing and Mapping of Road Surface Roughness based on GPS and Accelerometer Sensors on Bicycle-Mounted Smartphones. Sensors 2018, 18, 914.
https://www.mdpi.com/1424-8220/18/3/914

The research reporting a 10g acceleration came from 1986 when hitting deep potholes. it said forces were in random directions. The time to cross a pothole at say 15 mph, about 24 km/hr, 6.6m/sec, say 0.3m wide, would be about 0.045 seconds, less than a persons typical reaction time. the out of balance forces will occur before a person can react is the likely situation, assuming the surface defect has not been noticed prior to impact.

Assuming helmeted and non-helmeted ride identically except for wearing a helmet, both may encounter say, 1g - 3g during a typical 2 hour ride. The out of balance forces will be higher for helmeted on occasions. Riding on rough surfaces and gravel will also lead to g forces of perhaps 2g-4g accelerations.

page 11 of the paper refers to;
Other explanations for increased accident and injury occurrence for helmeted cyclist may be increased head diameter, impaired vision, impaired hearing, sideways wind shear and forces, reduced riding stability and loss of "safety in numbers" due to reduced cycling participation following helmet law enforcement
.
Reference to wind forces are
Fintelman, DM, Sterling, M, Hemida, H & Li, FX 2014, 'The effect of crosswinds on cyclists: An experimental study' Procedia Engineering, vol 72, pp. 720-725. DOI: 10.1016/j.proeng.2014.06.122
Brownlie L, Ostafichuk P, Tews E, Muller H, Briggs E , Franks K, The wind-averaged aerodynamic drag of competitive time trial cycling helmets, 8th Conference of the International Sports Engineering Association (ISEA), 1877-7058 c 2010 Published by Elsevier Ltd. https://www.sciencedirect.com/science/a ... 5810002638

Side wind forces may be extra for a typical cyclist wearing a helmet and combined with extra out of balance forces from g forces results in a higher fall off rate. It may well be possible to measure the degree of movements but not easy to compare riders who in practice will all be slightly different. Reproducing the 1986 research and measuring forces from helmets when encountering road surface defects should be feasible.
At the same time measuring the bicycle stability may be possible.

Robinson 1996 refers to the Wasserman data that detailed the incidence of cyclists hitting their head/helmet during an 18-month period was “significantly higher for helmet wearers (8/40 vs 13/476 - i.e. 20% vs 2.7%, p 0.00001)." A bare head width of approximately 150mm may avoid contact compared to a helmeted head at approximately 200mm wide (Clarke 2007 ). Assuming the 20% and 2.7% figures are typical, on a yearly average for helmeted and non-helmeted the risk of hitting their helmet or head would be 13.2% and 1.8% respectively. The increased risk of impact for helmeted is about seven times higher. A degree of protection could be expected plus a degree of risk from the extra impacts.


Extra falls and more helmet impacts compared to not wearing helmets, a general statement, based on available evidence

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pjclinch
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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 27 Aug 2020, 6:48am

There will be far, far more effect on suffering through potholes through tyre choice. The ones that suffer most will be narrow racing tyres. It is not entirely coincidental that sport riders, who tend to use helmets more, also use narrow, high pressure tyres more, and are likely to be going faster when they hit the potholes.
The problem would be worse with TT bikes, where the ride position makes seeing potholes in advance harder and the handling characteristics and ready access to brakes from the skis makes them harder to avoid. Ever see a TTer these days without a lid?
None of that is accounted for in papers like those you quote because of the simplistic assumption that the only differences between riders are whether or not they wear a helmet.

Cycle stability will be far more affected by geometry, steering trail, baggage loading etc. than whether you're wearing a lid. Anyone who's ever ridden a heavily laden bike will be well aware of this, particularly if it's not ideally laden. Anyone who's ridden a small wheel, low trail bike will be well aware of this. Anyone that's gone through potholes on a MTB vs a road bike will be aware of this. Ignoring all this (which is inevitable, because the data sources won't have it) is real elephant-in-the-room stuff.

Comparison work to show an effect of an intervention requires everything to be as similar as possible bar the intervention. Population work is very useful in showing cycling doesn't get significantly safer with rising helmet rates, but the nature of the data makes it hard to do more: it's too coarse grained. It doesn't tell you that a helmet is a cause of more falls.

I dismiss the likes of Thompson, Rivara and Thompson because the methodology is terrible. If I'm going to do that with "helmets are wonderful!' papers I am obliged to do it with "helmets are terrible!" papers that use the same simplistic assumption that everything different is down to a helmet. However detailed the calculations, they simply miss too much contextual data.
You end with "based on the available evidence", but the available evidence simply isn't good enough. That has to be recognised.

Pete.
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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 27 Aug 2020, 9:06am

Yes Pete it is judgement call to some extent.
The NZ data on whole population figures, that can be broken down by age group indicates the fall off rate increases. TT and MTB as a proportion of total cycling and total accidents is probably less than 10%. Some reports mention data but could take some finding.

Regardless of who is wearing a helmet, if they hit a large pothole and incur a high g force and did not see the pothole previously, the helmet is likely to add to out of balance forces and the rider would be at a higher risk of falling, Newtons law of motion.

The question to me is the percentage increase in the fall off rate. I would suggest extra research on the forces from helmets during typical and various forms of cycling.

I have a few bikes but nearly always ride the old bike with 27 x 1.25 tyres. If I ride the bike with narrow tyres, I would be more careful when required.

https://www.aph.gov.au/Parliamentary_Bu ... rt%20d/c02

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pjclinch
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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 27 Aug 2020, 9:38am

Steady rider wrote:Yes Pete it is judgement call to some extent.
The NZ data on whole population figures, that can be broken down by age group indicates the fall off rate increases. TT and MTB as a proportion of total cycling and total accidents is probably less than 10%. Some reports mention data but could take some finding.

Regardless of who is wearing a helmet, if they hit a large pothole and incur a high g force and did not see the pothole previously, the helmet is likely to add to out of balance forces and the rider would be at a higher risk of falling, Newtons law of motion.

The question to me is the percentage increase in the fall off rate. I would suggest extra research on the forces from helmets during typical and various forms of cycling.

I have a few bikes but nearly always ride the old bike with 27 x 1.25 tyres. If I ride the bike with narrow tyres, I would be more careful when required.

https://www.aph.gov.au/Parliamentary_Bu ... rt%20d/c02



The question to me is why are we worried about helmets here when there are so much more obvious factors affecting the question of "will I lose it if I hit a pothole". What tyres (width and pressure), what wheel size, what riding position, what handlebars, what suspension, what luggage (how much, where and how it's mounted), what fork geometry, how strong the front wheel is, if the rider is clipped in, what riding position they have adopted etc. etc.

All of these will be more significant, and all will vary by far more than the tiny effect of a lightweight helmet. I've been riding regularly for transport for over 40 years. I've been properly taken out by a pothole once in that time.

If you look at the June/July 2018 Cycle the cover has a lady with a splendid bit of headgear. That will create at least as much extra momentum as a typical EN1078 helmet, is that sort of thing a problem too? https://issuu.com/ctc_cyclists/docs/cycle.83.june_july_lite

Very prevalent in the UK is the use of rucksacks for luggage. Especially in riders who live on the drops that'll have greater motion effects in the case of going down a hole than a helmet, so where's the research effort in to rucksack wearing, where is the vitriol surrounding wearing/not waring rucksacks on a bike?

Pete.

[edited to add rucksack paragraph after seeing someone go by with one perched unsteadily]
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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 27 Aug 2020, 5:49pm

Yes most seem valid points but little data to connect each aspect with an increased accident rate. The difference between helmets and the other aspects is that helmets may contribute to head movement and there is data showing the impact rate is much higher than for a bare head when falls occur and data showing the accident rate is higher according to various indicators.

https://en.wikipedia.org/wiki/Righting_reflex

http://www.jvr-web.org/Download/Volume_ ... 2-3_a9.pdf

Helmet use is also subject to legislation and promotion in general terms, so it needs considering specifically and determining the total effects from their use. The film 'Concussion' was interesting to watch and avoiding helmet impacts is one message the film illustrates.

https://www.youtube.com/watch?v=RY1FQGd1Bb4

Jdsk
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Re: How to protect your brain by not wearing a helmet

Postby Jdsk » 27 Aug 2020, 5:53pm

Steady rider wrote:... and there is data showing the impact rate is much higher than for a bare head when falls occur...

What's the best single primary study that shows that, please?

Thanks

Jonathan

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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 27 Aug 2020, 6:06pm

Wasserman R.C, "Bicyclists, Helmets and Head
Injuries: A Rider-Based Study of Helmet Use
and Effectiveness". AJPH September 1988, Vol
78, No 9, pp 1220-21.

Jdsk
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Re: How to protect your brain by not wearing a helmet

Postby Jdsk » 27 Aug 2020, 6:23pm

That's the one with the Abstract, in full:
"We interviewed 516 bicyclists over age 10 regarding helmet use and head injuries. Although 19 per cent owned helmets, only 8 per cent were wearing them when interviewed. Riders wearing helmets were more highly educated and reported higher car seat belt use. Nearly 4 per cent of the bicyclists reported striking their heads in a cycling mishap during the previous 18 months; those wearing helmets at the time of the mishap were less likely to have sustained head injuries"."

And in the Results:
"Head injuries were reported by seven of 13 unhelmeted, and none of eight helmeted riders [odds ratio= 19.6,95% confidence interval(1.2, 31) ]. No associations were found between head injury and other variable, including the type of surface the head struck and involvement with a motor vehicle. In addition, helmet use was not associated with protection from nonhead injuries, suggesting that the injury events experienced by helmeted and unhelmeted riders were similar in severity.

and in the last paragraph:
"... these data offer very suggestive evidence that helmets afford protection from bicycling head injuries. Given the research design, it is also possible that a true association between helmets and protection from head injury might have been underestimated, since riders who had been kiled, severely injured, or who gave up riding would have been unavailable for interview at the time of the study. Future research should further define the role of helmets in reducing bicycling head injuries, and focus on ways to increase helmet use among bicyclists."

How do you get to
Steady rider wrote:... and there is data showing the impact rate is much higher than for a bare head when falls occur...

from that paper?

Thanks

Jonathan

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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 27 Aug 2020, 7:58pm

Robinson 1996 refers to the Wasserman data that detailed the incidence of cyclists hitting their head/helmet during an 18-month period was “significantly higher for helmet wearers (8/40 vs 13/476 - i.e. 20% vs 2.7%, p 0.00001)." see page 464

Robinson DL; Head injuries and bicycle helmet laws; Accid Anal Prev, 28, 4: p 463-475, 1996 http://www.cycle-helmets.com/robinson-head-injuries.pdf

They interviewed 516 cyclists at road side, 21 reported falling and hitting their heads, 8 were helmeted and 13 not. From 40 wearing helmets, 8 reported falling and hitting their heads. From 476 non-wearers, 13 reported falling and hitting their heads. 20% v 2.7%.

It may be worthwhile considering the differences that can occur between helmeted and non-wearers regarding the USA, http://worldtransportjournal.com/wp-con ... 4.4opt.pdf Table 12.
For example,
'A number of other factors for helmeted v no helmet could
also have a bearing - alcohol use (4.2% v 22.2%),

in the 40 sample, 4.2% would equate to 1 to 2 cyclists, and 22.2% in the 476 sample, 105-106 cases.

mikeymo
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Re: How to protect your brain by not wearing a helmet

Postby mikeymo » 29 Aug 2020, 12:15am

pjclinch wrote:Very prevalent in the UK is the use of rucksacks for luggage. Especially in riders who live on the drops that'll have greater motion effects in the case of going down a hole than a helmet, so where's the research effort in to rucksack wearing, where is the vitriol surrounding wearing/not waring rucksacks on a bike?


It must make things very top heavy. I remember seeing somebody cycling up Glencoe with a huge rucksack on, I assume touring. It looked all wrong, I just thought - get a rack and panniers.

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philg
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Re: How to protect your brain by not wearing a helmet

Postby philg » 29 Aug 2020, 5:42pm


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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 29 Aug 2020, 6:23pm

I expect braking may have played a part, was he braking at the time?

Another important thing that needs to be considered is the installation position of smartphones on bicycles. When the smartphone is fixed to different parts of a bicycle, different acceleration data might be recorded by the smartphone. Among all other places, the center of the handlebar seems to be a typical place for fixing smartphones on bicycles, according to cycling web platforms, like Cycling Weekly (http://www.cyclingweekly.com/) and ChinaBike (http://www.chinabike.net/). Therefore, in the current study, we fixed the smartphones to the center of the handlebar, as can be seen in Figure 4. We further discuss this issue in Section 5.

https://www.mdpi.com/1424-8220/18/3/914/htm

In this study, we fixed smartphones on the center of the bicycle handlebar. While this is a typical place where cyclists fix their smartphones, it might be interesting to investigate whether different installation positions on the bicycle lead to different measurement results. To comprehensively address this issue, the installation position of the smartphone should be considered together with the length of the wheelbase of the bicycle. In some extreme cases, the accelerometer sensor on the smartphone might be only subjected to angular acceleration. Therefore, it makes sense to investigate this issue in detail, and identify an optional installation position based on the length of a wheelbase.


Using several smart phones, say one on a rucksack, helmet and bicycle and using a standard course to test results may provide some data. The DfT or others may help with funding, see if CUK can help by asking for interested parties to contact them?

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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 30 Aug 2020, 8:48am



Kudos to him for the control he displayed... though I imagine he won the peloton's We Told You So! award for the day, presented by Captain Hindsight pointing out that Tony Martin might just know a thing or two about when to push it!

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Re: How to protect your brain by not wearing a helmet

Postby Steady rider » 30 Aug 2020, 7:20pm

I did wonder about the disc brakes and if they result in braking harder and a more difficult/quicker reaction slide to control.

I do not every recall so many riders having problems controlling their bikes in wet conditions.

Braking on the rim may result in less harsh braking and more time to control a slide?

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Re: How to protect your brain by not wearing a helmet

Postby pjclinch » 31 Aug 2020, 8:45am

Steady rider wrote:I did wonder about the disc brakes and if they result in braking harder and a more difficult/quicker reaction slide to control.

I do not every recall so many riders having problems controlling their bikes in wet conditions.

Braking on the rim may result in less harsh braking and more time to control a slide?


You should still be able to stream most of stage 1 on catchup. Conditions were bonkers, the roads were like rivers, it was the opening stage of Le Tour so very high stakes but nobody has had much real racing this year, and the chap in question had pointedly ignored a peoloton-suggested "take it steady boys" from Tony Martin, much egg oh Astana's face.

The thing about all the disc complaints are that discs have been completely normalised in 'cross for a few years and mountain bikes for far longer, so it really looks as if it's resistance to change rather than actual braking issues. The real issues are getting quick wheel changes, particularly from neutral service.

Pete.
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