why is there not a definative study about helments?

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Re: why is there not a definative study about helments?

Postby Vorpal » 12 Dec 2014, 3:09pm

TonyR wrote: Now in BMX nobody has done the studies AFAIK but why do you think that common sense works there and not on the roads? Certainly the helmets make your head a bigger target in an offie and you can almost guarantee that riders would not try such big stunts without the assumed protection of helmets.

I was going to post about BMX as a modern sport, but pjclinch beat me to it. What I will say is that the sort of BMX riding that kids do, and have done since the invention of BMX is often without helmets.

It's anecdotal, but there was an informal BMX track near the village in Essex where I lived, and lots of kids 'played' there on their bikes, and I seldom saw any helmets on the kids that used it. BMX club riders in the area wore helmets, but they didn't always when they were just riding around the village.

When BMX first became a thing in the USA, people didn't wear helmets. My friends and I built a BMX track in an abandoned quarry in the late 70s, and spent hours and hours there, jumping bikes, improving the track, racing on it, etc. I started with cheap and cheerful toy shop bikes, and broke a few frames, but never seriously injured myself. The only injuries I recall were a couple of kids who broke arms or collarbones doing it. I didn't know anyone who wore a helmet. The only protective gear that I can recall anyone wore was gloves.

I think that it is reasonable to wear protective equipment when doing activities that present higher risk. It is likely that the use of protective equipment influences behaviour, but we do not know to what extent. To say that BMX riders are injured more because they wear protective equipment has at least a couple of logical fallacies.
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Re: why is there not a definative study about helments?

Postby TonyR » 12 Dec 2014, 4:42pm

Vorpal wrote:To say that BMX riders are injured more because they wear protective equipment has at least a couple of logical fallacies.


And those are? The problem is you have no evidence to know whether protective equipment protects or causes harm. Its just an assumption that it will protect and as with helmets on the road, that assumption may well be wrong. There was a time when smoking was seen as a healthy activity that was encouraged by the medical profession. All sorts of cases were made as to why it was good for you. As we now know, it was completely wrong and it was the evidence that overturned their assumptions. There are even some who still think smoking is good for you. So what evidence do you have that wearing a BMX helmet does good not harm?

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Re: why is there not a definative study about helments?

Postby Steady rider » 12 Dec 2014, 5:13pm

It seems the degree of risk designed into the activity is proportional to the level of perceived protection.

I feel a bit sorry for these cyclists, if that is the right word, because the protection provided leads them to take high risks. I watched a bunch start into a banked bend and all trying to get the best position, off course someone gets injuries. Skill, fitness, power to determine a winner is in part exchanged for high risk taking. Kids watching these events may follow with the same approach. It is still interesting to watch but so is boxing.

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Re: why is there not a definative study about helments?

Postby pjclinch » 12 Dec 2014, 6:06pm

I would say the desire to win is a lot of why they take risks. The PPE probably pushes them harder, but it's also part of why it's spectacular, which drives people wanting to do it.
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Re: why is there not a definative study about helments?

Postby Vorpal » 12 Dec 2014, 10:50pm

TonyR wrote:
Vorpal wrote:To say that BMX riders are injured more because they wear protective equipment has at least a couple of logical fallacies.


And those are? The problem is you have no evidence to know whether protective equipment protects or causes harm. Its just an assumption that it will protect and as with helmets on the road, that assumption may well be wrong. There was a time when smoking was seen as a healthy activity that was encouraged by the medical profession. All sorts of cases were made as to why it was good for you. As we now know, it was completely wrong and it was the evidence that overturned their assumptions. There are even some who still think smoking is good for you. So what evidence do you have that wearing a BMX helmet does good not harm?

I don't have any evidence, and I wasn't trying to suggest that it does any good. I *suspect* like you, that there is at least an element of risk compensation at play.

However, that doesn't mean that we can draw any conclusions from the available information.

What evidence do we have? There is some evidence (from Elvik's studies) that people wearing helmets whilst cycling on the road go faster down hills. There is also some evidence that people who cycle in ANZ, where helmet laws have been implemented, have more crashes. And there is the theory of risk compensation.

This only establishes a correlation between speed and helmet wearing and between crashes and legislated helmet wearing. Increased risk taking is one logical explanation, but it is unproven. Correlation does not imply causation. [questionable cause fallacy] Also, in the case of crashes we cannot necessarily attribute the risk taking behavior solely to the helmet wearer. It is likely that at least some of the behavior occurs on the part of other who interact with the helmet wearer.
Even if one accepts that there is a correlation between risk taking and helmet wearing, it doesn't necessarily follow that an individual who wears a helmet will consequently take more risk [ecological fallacy].

Also, pjclinch was trying to say that the correlation between helmet wearing and crashes *may* not be valid for a completely different type of cycling, and I agree.

It does seem likely that there is a some element of risk compensation involved, we do not have enough information to determine how much, or what the impact is.

Accepting the likelihood of risk compensation, however, we still do not know if is it harmful, or beneficial to wear protective gear for BMX. It may be that risk compensation only compensates for a small part of a significant benefit, or it may be that risk compensation more than reverses a very small benefit.
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Re: why is there not a definative study about helments?

Postby pjclinch » 13 Dec 2014, 9:37am

We know "common sense" can misfire... but evidence saying it appears to misfire for a population dominated by utility cycling using a device for mitigation of minor injuries to try and affect serious ones (all the studies are looking at, they may well be using them for minor injuries but we don't have the data) in an environment where it turns out the risks are pretty low in any case (to the point that the most experienced cycling nations don't regard it as "common sense" to do anything about it with PPE) isn't actually that useful in informing another thing which we know is dangerous and does produce a high rate of injuries and where the PPE is about risk management because the main aim is winning and that's more likely, at least up to a point, with more risks taken, so risks are very deliberately taken.

At the end of the day, if one of my children was at the top of the start ramp on an Olympic BMX course and for some reason the helmet rules had been waived, would I sooner they trusted to the injury-informed experience of the other riders, or decided that since some doctors have thought smoking must be good for you in the past that "not proven" made it a good idea not to bother? Me, I'd go for the first one. Would I be 100% sure it was the best call? No. But that doesn't make it a bad call, or a dumb one, simply not a certain one.

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Re: why is there not a definative study about helments?

Postby drossall » 13 Dec 2014, 9:49am

No, but this is crucial:

pjclinch wrote:... using a device for mitigation of minor injuries ...

and applies even in the racing situation. Alongside the increased chance of accidents, about which you are of course correct, the best argument for helmets in racing is that the likely injuries are minor, and therefore some of them will be within the capacities of helmets.

However, the requirement for helmets in racing followed, it seems, from the unfortunate loss of Fabio Casartelli and one or two similar incidents. Without getting into an uninformed debate about a tragic incident of which we have little direct knowledge, it seems to me to be from first principles unlikely that helmets would help in most accidents involving hitting something solid at 40mph plus, which is far more like a traffic accident than falling off a BMX bike.

The current logic seems to me rather to parallel this line of thought:

  • I've been given this as a bullet proof vest. People aren't sure whether this design is effective against small arms, but I'm going to make jolly sure I'm wearing it when the only thing around is tank shells.

There's a case then that, whatever the effectiveness of the garment, it's just a distraction from focussing on getting rid of the tanks, or getting them to stop shooting.

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Re: why is there not a definative study about helments?

Postby TonyR » 13 Dec 2014, 10:34am

pjclinch wrote:At the end of the day, if one of my children was at the top of the start ramp on an Olympic BMX course and for some reason the helmet rules had been waived, would I sooner they trusted to the injury-informed experience of the other riders, or decided that since some doctors have thought smoking must be good for you in the past that "not proven" made it a good idea not to bother? Me, I'd go for the first one. Would I be 100% sure it was the best call? No. But that doesn't make it a bad call, or a dumb one, simply not a certain one.

Pete.


At the end of the day, if one of my children was at the start of a cycle to the shops would I sooner they trusted to the helmet-saved-my-life-informed experience of other riders?

No difference. You have no idea whether the helmet will make things worse or better, just faith that it will. If you are going to provide personal protective equipment, and especially if you are going to mandate it, then the equipment should be proven to protect and do no harm. Otherwise the answer to your question is if you are not prepared to see your daughter launch off that ramp without a helmet you shouldn't allow her to launch off at all. Because if that helmet is like road helmets and turns out to provide no protection you are just kidding yourself and she is at just as great a risk as launching off without one.

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Re: why is there not a definative study about helments?

Postby Vorpal » 13 Dec 2014, 10:47am

TonyR wrote:At the end of the day, if one of my children was at the start of a cycle to the shops would I sooner they trusted to the helmet-saved-my-life-informed experience of other riders?

No difference. You have no idea whether the helmet will make things worse or better, just faith that it will. If you are going to provide personal protective equipment, and especially if you are going to mandate it, then the equipment should be proven to protect and do no harm. Otherwise the answer to your question is if you are not prepared to see your daughter launch off that ramp without a helmet you shouldn't allow her to launch off at all. Because if that helmet is like road helmets and turns out to provide no protection you are just kidding yourself and she is at just as great a risk as launching off without one.

For me, it wouldn't be a matter of whether I was prepared to see my daughter launch without a helmet. Despite the risk, if my daughter was really keen to race BMX bikes, I would let her. The helmet question is taken out of our hands because they are required.

If they weren't, I would do my best to help her understand the risks and the debate about the usefulness of helmets, then support her informed decision.
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Re: why is there not a definative study about helments?

Postby TonyR » 13 Dec 2014, 12:10pm

Vorpal wrote:
TonyR wrote:At the end of the day, if one of my children was at the start of a cycle to the shops would I sooner they trusted to the helmet-saved-my-life-informed experience of other riders?

No difference. You have no idea whether the helmet will make things worse or better, just faith that it will. If you are going to provide personal protective equipment, and especially if you are going to mandate it, then the equipment should be proven to protect and do no harm. Otherwise the answer to your question is if you are not prepared to see your daughter launch off that ramp without a helmet you shouldn't allow her to launch off at all. Because if that helmet is like road helmets and turns out to provide no protection you are just kidding yourself and she is at just as great a risk as launching off without one.

For me, it wouldn't be a matter of whether I was prepared to see my daughter launch without a helmet. Despite the risk, if my daughter was really keen to race BMX bikes, I would let her. The helmet question is taken out of our hands because they are required.

If they weren't, I would do my best to help her understand the risks and the debate about the usefulness of helmets, then support her informed decision.


The mandatory bit is a red herring. The bottom line is until there is proof they offer a benefit, your best course of action is to not do it unless you would happily do it without a helmet. In which case you might as well do it without unless they are mandatory. The worst thing you can do is take more risk because you think you are protected when you are not.

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Re: why is there not a definative study about helments?

Postby Phil Fouracre » 13 Dec 2014, 12:18pm

As usual, spot on! Taking more risk because you think you are protected, this really is the crux of the discussion - so many have posted, and I have even heard myself, comments like 'I'll have to be more careful without my helmet on!!! Perhaps a crucifix or St Peter might be a better option.
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Re: why is there not a definative study about helments?

Postby pjclinch » 13 Dec 2014, 1:12pm

TonyR wrote:
pjclinch wrote:At the end of the day, if one of my children was at the top of the start ramp on an Olympic BMX course and for some reason the helmet rules had been waived, would I sooner they trusted to the injury-informed experience of the other riders, or decided that since some doctors have thought smoking must be good for you in the past that "not proven" made it a good idea not to bother? Me, I'd go for the first one. Would I be 100% sure it was the best call? No. But that doesn't make it a bad call, or a dumb one, simply not a certain one.


At the end of the day, if one of my children was at the start of a cycle to the shops would I sooner they trusted to the helmet-saved-my-life-informed experience of other riders?

No difference.


Actually a big difference. The "helmet saved my life" is an guess, the "well I've broken both my arms, and Billy here ruptured his spleen last year, and we usually see a good crash or two at every meet" is an accident record. They're not the same thing. The second demonstrates you are in a higher risk environment, the first does not.


TonyR wrote:You have no idea whether the helmet will make things worse or better, just faith that it will. If you are going to provide personal protective equipment, and especially if you are going to mandate it, then the equipment should be proven to protect and do no harm.


But it's very easy to show it protects at some level, which given the numbers concerned in bonkers BMX is really the best you're likely to manage in any case. You persist in confusing no benefit shown against serious injuries in a whole population with no benefit, period.

TonyR wrote: Otherwise the answer to your question is if you are not prepared to see your daughter launch off that ramp without a helmet you shouldn't allow her to launch off at all.


What I was getting at is that experience of people who do something a lot probably has more credence in terms of chances of advice being okay than saying you'll ignore it unless they can come up with peer reviewed citations. So I'd like prospective BMXers to listen to experienced BMXers about BMX rather than ignore them, it's no comment about me being prepared for her to go or not.

TonyR wrote: Because if that helmet is like road helmets and turns out to provide no protection you are just kidding yourself and she is at just as great a risk as launching off without one.


You persist in confusing no benefit shown against serious injuries in a whole population with no benefit, period. A lot of the benefit of a helmet in a sports context is not having your whole day written off by a relatively minor crash which leaves you with a damn awful headache but not much worse. Population studies of utility riders have no bearing on that whatsoever, so you continuing to harp on about "no protection" is not actually reasonable and misses the point of something like competitive BMX where a minor whack is relatively likely and can easily ruin a whole day's riding.

You really do need to take a step back and realise the granularity of "no benefit" claims. They're a bit like saying gloves are pointless when pulling nettles because people don't end up in hospital with the stings.

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Re: why is there not a definative study about helments?

Postby TonyR » 13 Dec 2014, 8:05pm

pjclinch wrote:But it's very easy to show it protects at some level, which given the numbers concerned in bonkers BMX is really the best you're likely to manage in any case. You persist in confusing no benefit shown against serious injuries in a whole population with no benefit, period.


And you persist in believing there must be a benefit despite no evidence to support your beliefs. Remember Diana Pettiti's four lessons - don't turn a blind eye to contradiction; do no be seduced by mechanism; suspend belief and maintain scepticism.

At least the road helmet proponents can claim to have evidence from studies like TRT even if it has been discredited. You on the other hand have nothing for BMX other than belief and "helmet saved my life" anecdotes.

You really do need to take a step back and realise the granularity of "no benefit" claims. They're a bit like saying gloves are pointless when pulling nettles because people don't end up in hospital with the stings.


Its very easy to do the control experiment with nettles by pulling them with and without gloves. That experiment is not possible with helmets and head impacts.

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Re: why is there not a definative study about helments?

Postby pjclinch » 13 Dec 2014, 9:07pm

TonyR wrote:
pjclinch wrote:But it's very easy to show it protects at some level, which given the numbers concerned in bonkers BMX is really the best you're likely to manage in any case. You persist in confusing no benefit shown against serious injuries in a whole population with no benefit, period.


And you persist in believing there must be a benefit despite no evidence to support your beliefs.


I'm 48. Therefore I have banged my head a lot of times. Quite often it hurts: not enough to report to anyone beyond the immediate folk hearing the air go blue, but enough to stop me what I'm doing for a few minutes and really wish I hadn't done it. Being a caver I've also banged my head a lot with a helmet on, and though it's a little annoying it doesn't hurt.

That is actually plenty of evidence to support my belief that a helmet is at least of some benefit in a situation where a head-whack is reasonably likely and could make a useful difference between carrying on and taking some time out. In a sporting context taking more time out means not finishing the race. Not having to abandon a race is a benefit in a sporting context.

The only benefits you're talking about are against serious head injuries. We're entirely on the same page there, but that's not the only possible value of "benefit".

TonyR wrote:At least the road helmet proponents can claim to have evidence from studies like TRT even if it has been discredited. You on the other hand have nothing for BMX other than belief and "helmet saved my life" anecdotes.


I've not brought life-saving (anecdotes or otherwise) in to it all, what are you on about? I am claiming it is entirely reasonable to expect helmets to do what they are designed to do: mitigate minor injuries by the simple fact of getting between a head and something unpleasantly abrasive and/or bruising. I don't actually need a peer reviewed citation to make that a reasonable assumption.

TonyR wrote:Its very easy to do the control experiment with nettles by pulling them with and without gloves. That experiment is not possible with helmets and head impacts.


It's the experiment that is abused as an example to "prove" we ought to be wearing them all the time in all situations if we're on a bike: put on a helmet and bang your head against a hard surface. Repeat with it off. Which one hurts more? If it's bare headed you have a helmet benefit. That's not a cause on its own to wear one to ride to the shops because there's a whole can of worms we're all aware of, but if you can't accept that a helmet's ability to absorb minor impacts and prevent some degree of headache is a benefit then you're being disingenuous. Is that a net benefit? That's impossible to answer, but in an environment where lots of small accidents are reasonable to expect (caving being something of an extreme example) then protection against them makes some sense, even if it does nothing for the serious stuff.

We all know "helmet saved my life" stories are on terribly shaky ground. But if everyone that had one changed it to "my helmet saved me a nasty headache for some minutes" would you believe them a bit more? I would. And though that's pretty small as benefits go it's still a benefit, and one which can make the difference between finishing a race and not.

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Re: why is there not a definative study about helments?

Postby Steady rider » 13 Dec 2014, 9:27pm

There is limited evidence on the risks involved in different types of off-road recreational cycling
(from family riding to downhill mountain biking etc) and cycle sport. Likewise, evidence on the
potential for helmet use to mitigate (or exacerbate) these risks is equally limited. These are in
any case not matters for road safety policy.
 For sporting events, CTC recognises the right of governing bodies to require the wearing of
helmets in line with their own and international regulations for these events, given the different
types of risk to which sport cyclists are exposed.


http://www.ctc.org.uk/sites/default/fil ... icybrf.pdf

If the potential benefits of helmets are exceeded by added risks from how events are organised or set up is probably difficult to quantify.