Helmets cramp my style
09-04-08, 09:20 AM
#3926
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I always like Andy Rooney's line about lottery winners and newspapers. He said, he'd like to see the newspapers print the names of not the winners of the lottery, but all those names of those who bought a ticket and lost. That way, people would have some sort of realistic perspective of what they were buying.
Maybe you'd feel different if you were to see helmeted cyclists injured. It's easy to show injured cyclists who were not wearing helmets because so few wear them, but once they do start to wear them, outside of a bit of superficial injury mitigation, they are just as injured as the ones who don't wear them.
Zealots, of course claim their injuries would have been worse without the helmet but there's no way they can show that's the case, they just shout loud enough to make it the case.
I have no problem with people wearing helmets, and I do so myself, but to claim life saving qualities when even the manufacturers do not claim this quality and no reduction of death has been recorded in any area that has adopted the widespread use of helmets, is bordering on zealotry and decidedly away from a reasonable analysis of their true quality.
Maybe you'd feel different if you were to see helmeted cyclists injured. It's easy to show injured cyclists who were not wearing helmets because so few wear them, but once they do start to wear them, outside of a bit of superficial injury mitigation, they are just as injured as the ones who don't wear them.
Zealots, of course claim their injuries would have been worse without the helmet but there's no way they can show that's the case, they just shout loud enough to make it the case.
I have no problem with people wearing helmets, and I do so myself, but to claim life saving qualities when even the manufacturers do not claim this quality and no reduction of death has been recorded in any area that has adopted the widespread use of helmets, is bordering on zealotry and decidedly away from a reasonable analysis of their true quality.
09-04-08, 10:11 AM
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yes it was. In 1943, and followed up by Gennarelli in 1974
Funny how this was researched long ago, the results not disputed, yet the results ignored by those who want to sell us helmets with the impression of protection from brain injury, but no claim of brain injury reduction, just a claim of impact absorption that can only be achieved through little to no forward momentum even though bicycles have been known to move forward, sometimes with much forward momentum...[/i]
Funny how this was researched long ago, the results not disputed, yet the results ignored by those who want to sell us helmets with the impression of protection from brain injury, but no claim of brain injury reduction, just a claim of impact absorption that can only be achieved through little to no forward momentum even though bicycles have been known to move forward, sometimes with much forward momentum...[/i]
John
09-04-08, 05:25 PM
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If that were the only criteria I had to go with, then yes, I'd take the one tested to the higher standard.
Now, suppose I decide to be a good consumer, and actually tried these two helmets on. I found that the one tested to the higher standard did not fit, and had a helmet retention system that was antiquated. When I tightened the chin strap, and got it adjusted, it still rotated significantly and would not stay in place. When I pushed up on it, it went high up on my forehead. When I rotated side-to-side, it had a significant wiggle to it.
But when I tried on the helmet with the lower standard, it fit very nicely, had an adjustable headband, and sat correctly on my head. I tried to push this helmet up onto my forehead, and it would not go. Wiggling my head side-to-side, the helmet stayed in place.
Now, suppose I decide to be a good consumer, and actually tried these two helmets on. I found that the one tested to the higher standard did not fit, and had a helmet retention system that was antiquated. When I tightened the chin strap, and got it adjusted, it still rotated significantly and would not stay in place. When I pushed up on it, it went high up on my forehead. When I rotated side-to-side, it had a significant wiggle to it.
But when I tried on the helmet with the lower standard, it fit very nicely, had an adjustable headband, and sat correctly on my head. I tried to push this helmet up onto my forehead, and it would not go. Wiggling my head side-to-side, the helmet stayed in place.
There's no direct evidence that I know of (and please correct me if you do have any) that indicates that the tighter fit of modern restraint systems actually make helmets safer. Just because helmet moves a bit on your head doesn't mean it won't protect you in an impact; what matters is that the helmet material is in-between your head and the object impacted. They certainly make helmets more comfortable, but safer? Where's the evidence, man?!!
My point is that, over the last twenty plus years, the standards are only one of the many factors that give a helmet a competitive advantage. People do look at safety, especially for their head, and that impacts what the helmet companies produce. Comfort is another issue, as well as fit. So there is not a single factor, such as the standard to which it is tested, that drives companies to develop better, and safer, helmets.
John
John
As I said before, I am not demonising them. They are commercial, profit-making enterprises, and act as such. If they were genuinely interested in developing safer helmets, they would be funding more rigorous research programmes (and as we have discussed, the research into helmet performance is hardly exceptional; it's taken years to even get to a paper which considers testing oblique impacts, which you helpfully linked for us). The fact that they are not funding such research indicates that improving the safety of the helmets they produce (beyond that required for the standards they need to meet in order to be able to sell them) is not a priority for them.
09-04-08, 06:34 PM
#3929
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I wonder at some of John's postings as well.
If he did indeed read some of Halbourn's work, (and there's no reason to think he did not) he must understand or be aware of the work involving the effects of different forces on the brain in impacts, yet he doesn't acknowledge it.
Even I don't turn a blind eye to some of the effectiveness of helmets, but it's important to understand it's shortcomings as well. A blind eye cannot be turned to shortcomings because with work, these shortcomings can be improved upon.
If he did indeed read some of Halbourn's work, (and there's no reason to think he did not) he must understand or be aware of the work involving the effects of different forces on the brain in impacts, yet he doesn't acknowledge it.
Even I don't turn a blind eye to some of the effectiveness of helmets, but it's important to understand it's shortcomings as well. A blind eye cannot be turned to shortcomings because with work, these shortcomings can be improved upon.
Last edited by closetbiker; 09-04-08 at 07:03 PM.
09-04-08, 07:37 PM
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Trombone,
Here is a quote from my Giro helmet manual:
One of our Trek bicycle manuals states:
Am I the only one who actually reads the owner’s manuals?
In addition, I know of at least two papers on the subject:
In short, fit is important to the protection of parts of the head, especially the forehead area. It is written into the helmet and bicycle manuals that fit is important too, and I really thought this was something all you us should already know as "common knowledge." But as I say in many of my training sessions at work, "common knowledge is only common if it is taught."
In the above paper’s discussion, there is this quote:
Note the sentence about helmet design, as it is important, and has improved greatly of late. This is why I thought it was a “no brainer” that helmets had improved over the years, but apparently this hasn’t gotten through yet. Hopefully, this food for thought will help.
By the way, in my own little informal survey today, 15 of 18 bicyclists I saw (myself not included) were wearing helmets. That's without a MHL here for adults. Two of those not wearing helmets were kids, who are covered on a MHL. But that's an 83% helmet wearing rate here today.
John
Here is a quote from my Giro helmet manual:
A Giro helmet can only protect you if it fits well. Make sure you try on different sizes and choose the size which feels secure and comfortable on your head. If properly fitted, this helmet is designed to stay on your head in an accident.
Wear a helmet
Trek urges all bicycle riders to wear helmets. An unprotected head is highly susceptible to injury, even from the slightest contact. There are many new helmets on the market which are both lightweight and comfortable. Trek recommends buying a helmet that is comfortable, fits properly, and meets ANSI and Snell safety testing standards. Trek has designed its own Trek brand helmets to meet the above standards (Fig. 20).
Trek urges all bicycle riders to wear helmets. An unprotected head is highly susceptible to injury, even from the slightest contact. There are many new helmets on the market which are both lightweight and comfortable. Trek recommends buying a helmet that is comfortable, fits properly, and meets ANSI and Snell safety testing standards. Trek has designed its own Trek brand helmets to meet the above standards (Fig. 20).
In addition, I know of at least two papers on the subject:
Pediatrics. 2003 Aug;112(2):320-3
Bicycle helmet assessment during well visits reveals severe shortcomings in condition and fit.
Parkinson GW, Hike KE.
Falmouth Pediatric Associates, Falmouth, Massachusetts 02540, USA.
gparkinson@massmed.org
BACKGROUND: Improper bicycle helmet fit increases the risk of head injury. Information on the rate of proper use of bicycle helmets is lacking. Promotion of helmet use is recommended at well-child and adolescent visits. Actual helmet assessment during such visits has not been reported. OBJECTIVES: The primary goal of this study is to measure the proportion of children whose helmets are in proper condition and can be made to fit properly by the child and/or parent. The secondary goal is to begin to assess the value and practicality of helmet inspection during well-child and adolescent visits. METHODS: The study took place at a private pediatric office in Falmouth, Massachusetts, from June 1 through August 31, 2001. Eligible children and adolescents were those aged 4 to 18 years presenting for well examination, along with siblings present at the visit. Eligible families completed a questionnaire, then had a timed attempt to fit a helmet, followed by an assessment of helmet fit and condition against a predetermined standard. RESULTS: Eighty-four percent (395/473) of eligible families participated. A total of 479 participants were assessed. Eighty-eight percent of participants (419/478) owned a helmet. Reported helmet use "always" or "almost always" was 73% for bicycling (317/434), 69% for in-line skating (193/279), 58% for scootering (179/310), and 50% for skateboarding (79/158). Compared with younger children, teenagers were less likely to wear helmets for all activities. Complete pass rate for every aspect of condition and fit was 4% (20/478, 95% confidence interval: 3-6). The pass rate when the parent alone fit the helmet was 0% (0/52). Three individual aspects of fit were most problematic: 1) helmet 'resting position' too high on the forehead (pass rate 249/479; 52%), 2) improper strap position (pass rate 157/476; 33%), and 3) excessive movement of the helmet from front to back of the head (pass rate 247/479; 52%). Mean time for questionnaire completion was 4 (standard deviation: +/-1) minutes, and 7 (standard deviation: +/-3) minutes for helmet assessment. CONCLUSIONS: Ninety-six percent of children and adolescents wore helmets in inadequate condition and/or with inadequate fit. This occurred despite a high acceptance of helmet use by this population. Initial evidence suggests that helmet assessment during well visits may be practical and valuable.
Bicycle helmet assessment during well visits reveals severe shortcomings in condition and fit.
Parkinson GW, Hike KE.
Falmouth Pediatric Associates, Falmouth, Massachusetts 02540, USA.
gparkinson@massmed.org
BACKGROUND: Improper bicycle helmet fit increases the risk of head injury. Information on the rate of proper use of bicycle helmets is lacking. Promotion of helmet use is recommended at well-child and adolescent visits. Actual helmet assessment during such visits has not been reported. OBJECTIVES: The primary goal of this study is to measure the proportion of children whose helmets are in proper condition and can be made to fit properly by the child and/or parent. The secondary goal is to begin to assess the value and practicality of helmet inspection during well-child and adolescent visits. METHODS: The study took place at a private pediatric office in Falmouth, Massachusetts, from June 1 through August 31, 2001. Eligible children and adolescents were those aged 4 to 18 years presenting for well examination, along with siblings present at the visit. Eligible families completed a questionnaire, then had a timed attempt to fit a helmet, followed by an assessment of helmet fit and condition against a predetermined standard. RESULTS: Eighty-four percent (395/473) of eligible families participated. A total of 479 participants were assessed. Eighty-eight percent of participants (419/478) owned a helmet. Reported helmet use "always" or "almost always" was 73% for bicycling (317/434), 69% for in-line skating (193/279), 58% for scootering (179/310), and 50% for skateboarding (79/158). Compared with younger children, teenagers were less likely to wear helmets for all activities. Complete pass rate for every aspect of condition and fit was 4% (20/478, 95% confidence interval: 3-6). The pass rate when the parent alone fit the helmet was 0% (0/52). Three individual aspects of fit were most problematic: 1) helmet 'resting position' too high on the forehead (pass rate 249/479; 52%), 2) improper strap position (pass rate 157/476; 33%), and 3) excessive movement of the helmet from front to back of the head (pass rate 247/479; 52%). Mean time for questionnaire completion was 4 (standard deviation: +/-1) minutes, and 7 (standard deviation: +/-3) minutes for helmet assessment. CONCLUSIONS: Ninety-six percent of children and adolescents wore helmets in inadequate condition and/or with inadequate fit. This occurred despite a high acceptance of helmet use by this population. Initial evidence suggests that helmet assessment during well visits may be practical and valuable.
In the above paper’s discussion, there is this quote:
DISCUSSION
This is the first study to examine the issue of helmet condition and fit in detail. In short, even in our controlled setting, the overwhelming majority of children, adolescents and their parents cannot properly fit a bicycle helmet. This is true regardless of age, gender, level of education or frequency of bicycle use. By measuring the different components of condition and fit, it was possible to specifically identify the problem areas. There were 3 particular problems: 1) resting position too high on the forehead, 2) improper strap position and, as a result, 3) excessive helmet movement from front to back off the forehead. All of these factors expose the frontal region, the most common site of impact in bicycle head injuries. [12][14]
In 1989, Thompson et al [8] reported that helmet use reduced the incidence of bicycle related head injury by 85%. According to Consumer Product Safety Commission date, [15] helmet use increased from 18% in 1991 to 59% in 1999. Reported overall helmet use in this study was high (73% overall for bicycles). Although the validity of this data depends on reporting accuracy, this rate of helmet use would be one reason for cautious optimism.
However, Rivara et al [1] reported that improper helmet use is estimated to increase the risk of head injury by a factor of 3. In this light, our data suggests that most children and adolescents are receiving suboptimal head protection. Increased attention to teaching of helmet fit skills is required. We speculate that repeated reenforcement of proper helmet use techniques (ie, practice) will improve helmet fit rates. Possible locations for ntervention include retail outlets, schools, bicycle rodeos, and (potentially) sites of pediatric care. A similar multimimentional approach has been shown effetive for increasing the rate of helmet use [16-19] Improvements in helmet design could also potentially simplify the process…
This is the first study to examine the issue of helmet condition and fit in detail. In short, even in our controlled setting, the overwhelming majority of children, adolescents and their parents cannot properly fit a bicycle helmet. This is true regardless of age, gender, level of education or frequency of bicycle use. By measuring the different components of condition and fit, it was possible to specifically identify the problem areas. There were 3 particular problems: 1) resting position too high on the forehead, 2) improper strap position and, as a result, 3) excessive helmet movement from front to back off the forehead. All of these factors expose the frontal region, the most common site of impact in bicycle head injuries. [12][14]
In 1989, Thompson et al [8] reported that helmet use reduced the incidence of bicycle related head injury by 85%. According to Consumer Product Safety Commission date, [15] helmet use increased from 18% in 1991 to 59% in 1999. Reported overall helmet use in this study was high (73% overall for bicycles). Although the validity of this data depends on reporting accuracy, this rate of helmet use would be one reason for cautious optimism.
However, Rivara et al [1] reported that improper helmet use is estimated to increase the risk of head injury by a factor of 3. In this light, our data suggests that most children and adolescents are receiving suboptimal head protection. Increased attention to teaching of helmet fit skills is required. We speculate that repeated reenforcement of proper helmet use techniques (ie, practice) will improve helmet fit rates. Possible locations for ntervention include retail outlets, schools, bicycle rodeos, and (potentially) sites of pediatric care. A similar multimimentional approach has been shown effetive for increasing the rate of helmet use [16-19] Improvements in helmet design could also potentially simplify the process…
By the way, in my own little informal survey today, 15 of 18 bicyclists I saw (myself not included) were wearing helmets. That's without a MHL here for adults. Two of those not wearing helmets were kids, who are covered on a MHL. But that's an 83% helmet wearing rate here today.
John
Last edited by John C. Ratliff; 09-04-08 at 07:43 PM.
09-04-08, 10:42 PM
#3931
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Thanks for the paper, John; I am familiar with this research.
Interestingly, if you take it at face value, it shows that badly fitted helmets are extremely effective at preventing head injury.
In reality, it doesn't really show anything much at all, other than that a lot of people have problems fitting their helmets correctly.
It asserts at the beginning that badly fitted helmets increase the risk of head injury. It offers no quantification of that statement, nor comparator (risk increases compared to what? I'm being a bit harsh here, but precision is important in academic research, and it is lacking in this paper).
It does nothing to demonstrate that they are less effective, which was my initial question.
I'm also highly doubtful about any research from 2003 that relies on that discredited 1989 Thompson et al paper. Frankly, for me this loses all credibility at this point. Research needs to build on the latest and best findings, not outdated and superseded research.
The last point, about improvements in helmet design, also supports my point about the manufacturers not prioritising making safer helmets. If they were, they would have been carrying out this type of research, as part of an R&D programme to develop better restraint systems focussed both on ensuring the helmet was comfortable, and was also hard / impossible to fit incorrectly on the head. I don't see them carrying out that research, nor evidence that they are focussed on anything other than the former.
Interestingly, if you take it at face value, it shows that badly fitted helmets are extremely effective at preventing head injury.
In reality, it doesn't really show anything much at all, other than that a lot of people have problems fitting their helmets correctly.
It asserts at the beginning that badly fitted helmets increase the risk of head injury. It offers no quantification of that statement, nor comparator (risk increases compared to what? I'm being a bit harsh here, but precision is important in academic research, and it is lacking in this paper).
It does nothing to demonstrate that they are less effective, which was my initial question.
I'm also highly doubtful about any research from 2003 that relies on that discredited 1989 Thompson et al paper. Frankly, for me this loses all credibility at this point. Research needs to build on the latest and best findings, not outdated and superseded research.
The last point, about improvements in helmet design, also supports my point about the manufacturers not prioritising making safer helmets. If they were, they would have been carrying out this type of research, as part of an R&D programme to develop better restraint systems focussed both on ensuring the helmet was comfortable, and was also hard / impossible to fit incorrectly on the head. I don't see them carrying out that research, nor evidence that they are focussed on anything other than the former.
Last edited by trombone; 09-04-08 at 10:48 PM.
09-05-08, 12:40 AM
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Thanks for the paper, John; I am familiar with this research.
Interestingly, if you take it at face value, it shows that badly fitted helmets are extremely effective at preventing head injury.
In reality, it doesn't really show anything much at all, other than that a lot of people have problems fitting their helmets correctly.
It asserts at the beginning that badly fitted helmets increase the risk of head injury. It offers no quantification of that statement, nor comparator (risk increases compared to what? I'm being a bit harsh here, but precision is important in academic research, and it is lacking in this paper).
It does nothing to demonstrate that they are less effective, which was my initial question.
I'm also highly doubtful about any research from 2003 that relies on that discredited 1989 Thompson et al paper. Frankly, for me this loses all credibility at this point. Research needs to build on the latest and best findings, not outdated and superseded research.
The last point, about improvements in helmet design, also supports my point about the manufacturers not prioritising making safer helmets. If they were, they would have been carrying out this type of research, as part of an R&D programme to develop better restraint systems focussed both on ensuring the helmet was comfortable, and was also hard / impossible to fit incorrectly on the head. I don't see them carrying out that research, nor evidence that they are focussed on anything other than the former.
Interestingly, if you take it at face value, it shows that badly fitted helmets are extremely effective at preventing head injury.
In reality, it doesn't really show anything much at all, other than that a lot of people have problems fitting their helmets correctly.
It asserts at the beginning that badly fitted helmets increase the risk of head injury. It offers no quantification of that statement, nor comparator (risk increases compared to what? I'm being a bit harsh here, but precision is important in academic research, and it is lacking in this paper).
It does nothing to demonstrate that they are less effective, which was my initial question.
I'm also highly doubtful about any research from 2003 that relies on that discredited 1989 Thompson et al paper. Frankly, for me this loses all credibility at this point. Research needs to build on the latest and best findings, not outdated and superseded research.
The last point, about improvements in helmet design, also supports my point about the manufacturers not prioritising making safer helmets. If they were, they would have been carrying out this type of research, as part of an R&D programme to develop better restraint systems focussed both on ensuring the helmet was comfortable, and was also hard / impossible to fit incorrectly on the head. I don't see them carrying out that research, nor evidence that they are focussed on anything other than the former.
You state that because it mentions in passing the Franklin report, that it looses credibility. They you apparently missed completely this statement:
However, Rivara et al [1] reported that improper helmet use is estimated to increase the risk of head injury by a factor of 3.
What is of interest to me is that Closetbiker is stating that he sees no data saying that, on an epidemiological basis, helmet laws work. We have studies that show definitively that the helmets work within the design limitations for mitigating injuries from falls. We have data here saying that helmets, when not fitted correctly, do not protect by an estimated factor of 3. Could all of this be tied together, and cause some of the lack of data that Closetbiker is asking for?
On another level, when a bicycle helmet is sold at your LBS, how long does the store attendant spend showing the person, especially parents or children, how to fit the helmet? Or do they spend any time at all? Department stores don't have the expertise to show this, so most likely these people do not get any kind of training at all. Does this fit into the overall equation of bicycle injuries?
More food for thought, and it's late here so I'll quit for now.
John
09-05-08, 01:21 AM
#3933
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You know, as a safety and health professional, I find it very interesting that you would think that ill-fitting PPE (personal protective equipment) will function as expected. It doesn't occur with hearing protection, it doesn't occur with respirators, it doesn't occur with eye protection, so why should it occur with head protection?
The paper you quoted indicated that 96% of people had their helmets fitting incorrectly. Assuming this is representative, this means that 96% of cyclists have badly fitted helmets.
They then quote the the extraordinary levels of protection offered by helmets (85% reduction head injury!) from the Thompson report. That report as based upon a general sample of cyclists, not a sample of those who had correctly fitted helmets. So if both papers are correct, it means that this is the level of protection offered by badly fitted helmets (actually it could be very slightly less, but the 4% of the sample that would have been correctly fitted is not enough to swing the result very much in any case).
Wow. Badly fitted helmets can reduce head injuries by close to 85%!
And double wow! This result was obtained despite the fact these people were three times more likely to receive a head injury than someone wearing a correctly fitted helmet! So if everyone wore correctly fitted helmets, we'd be reducing head injuries by, erm, 255%! Hang on, that can't be right...
The stats just don't add up, John.
God catch, I missed this in my original reading. Sorry. I don't know this paper, and would be keen to read it. However, the quality of Rivara's other work hardly inspires confidence in me, especially considering the way the odds stack up as explained above. Something is fishy here...
09-05-08, 08:17 AM
#3934
Senior Member
Yeah, that's quite a posting John made in response to your post. I've had similar responses from John after a couple of my posts. It makes it hard to discuss when posts are made about something that was never on the table to begin with. It's one of the problems I have when John responds. I'm not confident he's reacting to what was posted but something else going on in his mind.
Rivera is something of a questionable researcher on this topic. Prior to the report in question, he was already engaged in surveying and lobbying for helmet use.
Read, "Bicycle helmet use by children. Evaluation of a community-wide helmet campaign." Journal of the American Medical Association 1989;262:2256-61.
Read, "Bicycle helmet use by children. Evaluation of a community-wide helmet campaign." Journal of the American Medical Association 1989;262:2256-61.
Last edited by closetbiker; 09-05-08 at 10:24 AM.
09-05-08, 10:15 AM
#3935
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Trombone,
In my statement above, I was reacting to this comment of yours:
This is where I thought you were saying that ill-fitting PPE is still safe. Is this not what you are stateing here? I ask because in a subsequenet post, you say in reply to my statement below,
So I guess I'm a bit confused.
Loose, ill-fitting helmets can move during a crash, in response to centripital force and inertia. If they leave vital areas, such as the forehead or the temple areas unprotected in a fall, then they are not of much use.
Today, I drove to work, but did see four bicyclists, all of whom had hemets on--100%.
John
In my statement above, I was reacting to this comment of yours:
There's no direct evidence that I know of (and please correct me if you do have any) that indicates that the tighter fit of modern restraint systems actually make helmets safer. Just because helmet moves a bit on your head doesn't mean it won't protect you in an impact; what matters is that the helmet material is in-between your head and the object impacted. They certainly make helmets more comfortable, but safer? Where's the evidence, man?!!
Originally Posted by John C. Ratliff
You know, as a safety and health professional, I find it very interesting that you would think that ill-fitting PPE (personal protective equipment) will function as expected. It doesn't occur with hearing protection, it doesn't occur with respirators, it doesn't occur with eye protection, so why should it occur with head protection?
Originally Posted by Trombone
That's not what I think, and not what I stated. However, you can draw that conclusion from the research
Loose, ill-fitting helmets can move during a crash, in response to centripital force and inertia. If they leave vital areas, such as the forehead or the temple areas unprotected in a fall, then they are not of much use.
Today, I drove to work, but did see four bicyclists, all of whom had hemets on--100%.
John
09-05-08, 05:55 PM
#3936
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OK, apologies if I wasn't clear. Let me clarify.
Saying 'I do not know of any evidence' is not the same thing as saying 'I think'. Yes, of course it intuitively seems likely that tighter fitting helmets would work better. But intuition is a poor substitute for empirical evidence.
And as I then pointed out, if we take all these papers at face value, the 'expected' performance of helmets (eg the 85% reduction figure) is being delivered against a background of 96% of cycle helmets being incorrectly fitted.
I thought it was an interesting idea that all the statistics about helmet effectiveness drawn from hospital admissions data represent predominantly mis-fitted helmets.
Saying 'I do not know of any evidence' is not the same thing as saying 'I think'. Yes, of course it intuitively seems likely that tighter fitting helmets would work better. But intuition is a poor substitute for empirical evidence.
And as I then pointed out, if we take all these papers at face value, the 'expected' performance of helmets (eg the 85% reduction figure) is being delivered against a background of 96% of cycle helmets being incorrectly fitted.
I thought it was an interesting idea that all the statistics about helmet effectiveness drawn from hospital admissions data represent predominantly mis-fitted helmets.
09-05-08, 07:30 PM
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OK, apologies if I wasn't clear. Let me clarify.
Saying 'I do not know of any evidence' is not the same thing as saying 'I think'. Yes, of course it intuitively seems likely that tighter fitting helmets would work better. But intuition is a poor substitute for empirical evidence.
And as I then pointed out, if we take all these papers at face value, the 'expected' performance of helmets (eg the 85% reduction figure) is being delivered against a background of 96% of cycle helmets being incorrectly fitted.
I thought it was an interesting idea that all the statistics about helmet effectiveness drawn from hospital admissions data represent predominantly mis-fitted helmets.
Saying 'I do not know of any evidence' is not the same thing as saying 'I think'. Yes, of course it intuitively seems likely that tighter fitting helmets would work better. But intuition is a poor substitute for empirical evidence.
And as I then pointed out, if we take all these papers at face value, the 'expected' performance of helmets (eg the 85% reduction figure) is being delivered against a background of 96% of cycle helmets being incorrectly fitted.
I thought it was an interesting idea that all the statistics about helmet effectiveness drawn from hospital admissions data represent predominantly mis-fitted helmets.
Just realize that this is your conclusion, and did not come from the study. The study addressed the fit of helmets only. The reference you talk about was in the discussion section, and not the results section. And by the way, I meant to say that you were thinking along those directions, as evidenced by your comment, and not that "you think" exactly this way; I stand corrected.
Today's numbers were 15 of 22 people riding bicycles were riding with helmets. That's 68% usage. I noted several with mal-adjusted helmets and/or head straps. Interestingly, the ones without the helmets were kids under 18, some of whom were on BMX bikes coming from a skate park. There is no MHL here for adults, but all the adults were wearing helmets. There is a MHL for kids, but only a couple were wearing them.
John
Last edited by John C. Ratliff; 09-05-08 at 07:44 PM. Reason: add text and context
09-06-08, 01:57 AM
#3938
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The study you cited indicates that most cyclists do not fit their helmets correctly. If this is true (and if you don't think it is true, then you are rejecting the study), then it follows that the majority of the general population of cyclists are riding around with mis-fitted helmets.
The studies which show the reduction in head injury - like the 85% figure quoted - are based on studies of the general population of cyclists. I'm assuming you believe this is true; if it is not again the study becomes invalid.
So taking those two truths we conclude that the 85% reduction in head injury comes about despite the fact that most cyclists have mis-fitting helmets.
Finally we also have a study that seems to say mis-fitted helmets lead to a three-fold increase in risk of head injury. I don't have that paper, but let us assume that this is correct on face value. (note that if it is not correct on face value, then it has been quoted incorrectly in the first paper which is not a good reflection on the quality of that research).
Assuming you agree with the logic up until now (and assuming you think the research papers are valid), you now have to conclude that the 85% figure could be very significantly improved upon if everyone were to start fitting their helmets correctly. Indeed, the figure seems to rise to above 100%, although without having the original paper it is hard to quantify exactly was is meant by 'three-fold'.
I'm not making any conclusion or leap of faith here. If you think all three of those papers are correct, this is the inescapable conclusion you reach. If you think that conclusion sounds fishy, then it has to be the case that at least one of the papers has an error.
Do you agree with the conclusion that the 85% figure could be very significantly improved upon if people started fitting their helmets correctly?
09-07-08, 07:16 PM
#3939
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Trombone,
I'm going to reply, but things are getting busy. I do not agree with your logic, and therefore it will take me a few days to compose a response. Please be patient.
John
I'm going to reply, but things are getting busy. I do not agree with your logic, and therefore it will take me a few days to compose a response. Please be patient.
John
Last edited by John C. Ratliff; 09-07-08 at 07:16 PM. Reason: remove repeated phrase.
09-08-08, 06:22 AM
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No worries, John. I know you are busy. Are you still studying?
09-08-08, 04:04 PM
#3941
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not assumptions John. It's based on examination of facts
You're familialar with New Zealands example:
This next graph shows head injuries to cyclists that do not involve a motor vehicle. Just a scenario that fits into the the design performance of helmets.
Show the year that the law was introduced and police enforced an over 90% compliance rate of wear
You're familialar with New Zealands example:
This next graph shows head injuries to cyclists that do not involve a motor vehicle. Just a scenario that fits into the the design performance of helmets.
Show the year that the law was introduced and police enforced an over 90% compliance rate of wear
What explains the reduction of "all" head injuries? What explains the reduction of "bicycling" head injuries? Is there one explanation for both? Or are there different explanations for different subpopulations? What is the detail for the "all" numbers (ie, how are these people hurting their heads)? What percentage of overall head injuries are bicycle related?
It looks like there was about a 20% reduction in head injuries. We don't know what caused the reduction. Would a 10% difference in the %change rate (ie, 2%)be noticible? Would a 20% difference? Maybe the data isn't sensitive enough to show the benefits of wearing helmets.
Note that the source for the top graph is using it to refute the statement that "there is an 85% reduction in head injuries with helmets". (I think it serves that purpose pretty-well.)
https://www.chapmancentral.co.uk/wiki...est_helmet_lie
Last edited by njkayaker; 09-08-08 at 04:15 PM.
09-08-08, 04:52 PM
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IOW, the rational person looks at the side curtain air bag statistics and says "Well, you're probably a little safer in a car with side curtain airbags". The irrational person rolls down the window and screams epithets at passing motor traffic about how they deserve to die because they don't have them.
09-08-08, 09:42 PM
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Could someone please link the original paper by Dr. Nigel Perry here. Simply seeing Dr. Perry's graph without the context of the paper doesn't tell us much. In the paper here:
https://www.chapmancentral.co.uk/wiki..._helmet_debate
tries to show a table that goes from 1990 to 1996 to this graph, which goes from 1988 to 1996.
Again, it is getting busy trombone, and I will answer your question logic. This post took only a couple of minutes, while researching the logic for your post will take longer, as you have thought it through. And...classes started today, a week late as the hurricane evacuated New Orleans.
John
https://www.chapmancentral.co.uk/wiki..._helmet_debate
tries to show a table that goes from 1990 to 1996 to this graph, which goes from 1988 to 1996.
Again, it is getting busy trombone, and I will answer your question logic. This post took only a couple of minutes, while researching the logic for your post will take longer, as you have thought it through. And...classes started today, a week late as the hurricane evacuated New Orleans.
John
Last edited by John C. Ratliff; 09-09-08 at 07:20 PM. Reason: Correct spelling error
09-08-08, 10:58 PM
#3944
You gonna eat that?
Why wear a helmet? Because after doing a faceplant on concrete, this was the worst of my injuries:
If I didn't have a helmet, it would have been my skull that cracked in half instead.
If I didn't have a helmet, it would have been my skull that cracked in half instead.
09-08-08, 11:16 PM
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Glad you`re OK, Doohickie. How did you end up doing a faceplant?
09-08-08, 11:29 PM
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seriously, in the past three weeks I witnessed one crash and treated a second crash victim both of whom were wearing full face helmets, and the helmets saved both of them from broken teeth, broken jaws or worse.
full face helmet
'normal' helmet
09-09-08, 09:10 AM
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I know that this has been said before, but even though I question how much protection a helmet offers, I still wear one.
09-09-08, 01:23 PM
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Insults are a bizarre (and ineffective) way to make an argument.
Last edited by njkayaker; 09-09-08 at 01:26 PM.
09-09-08, 11:57 PM
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Originally Posted by trombone post #3938
Originally Posted by John C. Ratliff
by the way, I meant to say that you were thinking along those directions, as evidenced by your comment, and not that "you think" exactly this way; I stand corrected.
Originally Posted by John C. Ratliff
Just realize that this is your conclusion, and did not come from the study. The study addressed the fit of helmets only. The reference you talk about was in the discussion section, and not the results section.
The study you cited indicates that most cyclists do not fit their helmets correctly. If this is true (and if you don't think it is true, then you are rejecting the study), then it follows that the majority of the general population of cyclists are riding around with mis-fitted helmets.
The studies which show the reduction in head injury - like the 85% figure quoted - are based on studies of the general population of cyclists. I'm assuming you believe this is true; if it is not again the study becomes invalid.
So taking those two truths we conclude that the 85% reduction in head injury comes about despite the fact that most cyclists have mis-fitting helmets.
Finally we also have a study that seems to say mis-fitted helmets lead to a three-fold increase in risk of head injury. I don't have that paper, but let us assume that this is correct on face value. (note that if it is not correct on face value, then it has been quoted incorrectly in the first paper which is not a good reflection on the quality of that research).
Assuming you agree with the logic up until now (and assuming you think the research papers are valid), you now have to conclude that the 85% figure could be very significantly improved upon if everyone were to start fitting their helmets correctly. Indeed, the figure seems to rise to above 100%, although without having the original paper it is hard to quantify exactly was is meant by 'three-fold'.
I'm not making any conclusion or leap of faith here. If you think all three of those papers are correct, this is the inescapable conclusion you reach. If you think that conclusion sounds fishy, then it has to be the case that at least one of the papers has an error.
Do you agree with the conclusion that the 85% figure could be very significantly improved upon if people started fitting their helmets correctly?
First point, from above, that most cyclists do not wear properly fitted helmets. Actually, that study was done in well-child visits:
OBJECTIVES: The primary goal of this study is to measure the proportion of children whose helmets are in proper condition and can be made to fit properly by the child and/or parent. The secondary goal is to begin to assess the value and practicality of helmet inspection during well-child and adolescent visits.
To be continued...