11 Latest Research : Bicycles Second To Automobiles In Child Injuries

Comment#30 or so from my last post really bothered me. I thought I'd address this and make some things really clear here, just to show everyone the severity of what we're looking at.

Here's that comment, delivered by an anonymous poster :

"As someone who has been closely affected by a loved one who died from a head injury I have to ask, what is it about riding a bicycle that brings up this issue? Does this happen to people on bicycles more than others, because I don't think it does.

The loved one I knew that died did so from falling down the stairs, not riding a bicycle. In my long life, i have also known others that have been hospitalized with head injuries from falls off ladders and automobile accidents as well. I paid attention when Dr. Atkins died from a head injury while walking on an icy sidewalk because I was on his diet at the time.

I don't understand why these head injuries seem to be getting ignored yet bicycle injuries get attention. I'm no scientist but I don't think it takes one to see there are far fewer of these injuries happening to people riding bikes than all those others.

In the memory of the one I loved, I would ask everybody to put this into perspective and not ignore the many and focus on a few. From the way I see this being played out around the neighborhood, no one seems to have any sense of perspective anymore. When I grew up, riding a bicycle was a good healthy thing to do and the only ones that ran into problems doing it were the ones who lacked a lick of common sense and probably would have had a similar problem doing something else because they lacked the common sense to behave safely in the first place."

Dear Anonymous,

I'm deeply sorry to hear about your loved one. While your comment is relevant and hearing about any kind of head injury is sad, realize two important things.

1) I'm addressing bicycling chiefly because I'm interested in exploring the bicycle as a consumer product on this blog and any interesting issues related to it.

2) One of the latest papers in the March 2009 publication of Clinical Pediatrics (Vol 48, No. 2) spells out the bad news for all of us in more clearer terms than I have seen anywhere else.

The paper is titled "Bicycle Related Injuries Among Children And Adolescents In The United States" authored by professionals from the Nationwide Children's Hospital Research Institute : Tracy J. Mehan, MA, Ricky Gardner, BS, Gary A. Smith, MD, Dr P.H and Lara B. McKenzie, PhD, MA.

Clipping 1 : The only consumer product associated with more childhood injuries than bicycles in the U.S are automobiles. Ouch.

Clipping 2 : The research involved a 16 year study of bicycling–related injuries treated in US emergency departments (EDs) using the CPSC NEISS (National Electronic Injury Surveillence System). The NEISS receives data from a network of approximately 100 hospitals that represent a stratified probability sample of 6100 hospitals with at least 6 beds and a 24-hour ED. The database provides information regarding injury events presenting to participating hospitals, including the patient’s age, sex, race/ ethnicity, injury diagnosis, body part injured, products involved, disposition from the ED, and a brief narrative of the incident. Each year, the NEISS provides data on approximately 500 000 injury-related ED visits. The probability sample method of the NEISS allows the use of statistical weights to make nationally representative estimates of the number of injurious events. What is to be remembered is that these are strictly ED cases, and exclusive of all other types of lesser injuries associated with bicycles.


Clipping 3 : For the 16 year research period, 6,228,700 children and adolescents (confidence interval 95% (95% CI, 5 439,376-7,018,002) under 18 years were treated in ED for bicycle related injuries. This represents a mean of 389,300 patients annually. The number of injuries decreased slightly during the 16 years studied; however, even in the year with the fewest injuries, there was a mean of more than 850 bicycle-related injury events per day.

Clipping 4 : Whats most interesting and revealing is this detailed epidemiology and breakdown of injuries, something no other research paper will provide you with. The head ranks among the top 4 body parts injured accounting for 12.4%. Anything within that bound may be fatal. In this study, children with head injuries were significantly more likely to require hospitalization and to have their injuries result in death.


Clipping 5 : And here's something for the product design people...just so you're aware that handlebars are causing abdominal injuries in children, so are wheel spokes. The authors offer two suggestions for design improvements. Remember, these are kids. Not experienced riders.


Clipping 6 : This research provides an important nationally representative analysis of bicycle-related injuries occurring to children and adolescents in the United States. These injuries continue to be a major problem for US children. According to Healthy People 2010, increasing bicycle safety is a national priority.

I hope I was able to clear any misconceptions in your mind and put a better perspective into what we're dealing with here. Child safety on bicycles is not to be taken lightly. The people who can really help are the ones designing bicycles for children, parents, and any volunteers who can cheer-lead and encourage safer biking practices among children. Shunning helmets and teaching kids to do the same is not the way to go.

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105 Statisculation & Sporting Prejudice In Anti-Helmet Propaganda

This post is In Memory Of Andrew Callighan, who died 21 April (Saturday), two days after he was struck by a pickup truck while riding his bicycle in Michigan. Andrew, who was not wearing a helmet, was thrown several feet from his bike by the impact of the crash and was found on the side of the road when police and other rescue workers arrived. He sustained severe and multiple skull fractures and was pronounced dead Saturday at Helen Devos Children's Hospital in Grand Rapids. Michigan has no state law regarding the use of bicycle helmets.

Get your coffee ready. We're going to explore 2 topics that I feel must be addressed. Each of those 2 topics involves a detailed case study (highlighted in blue font), and my comments are given below a table, or graph. My primary audience are the folks who use mis-information to suggest that helmets cause not only a decrease in cycling, but a host of other problems, some of which we will cover. I do not necessarily support mandatory helmet legislation, and don't give a damn about what is policy and what isn't. But I don't understand the logic of people who will use everything in their arsenal to fight law, if they are given the chance. I reckon at least 90% of these people would shut up if they had no 'mis-information', flawed or half baked research articles and spurious surveys to feed from in the first place. Helmets have their limitations, and I have no assumptions about them having super powers. While I do call for safety, what I'm calling for more is good research, accounting for alternative explanations, and applying caution and critical reading skills before believing in or spreading the material in research papers around.

Example : Mr. Burton, a transport planner, takes it upon himself to inform others that he read 'something' , somewhere that suggests helmets do zilch for safety.

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INTRODUCTION

There's that saying that when your number comes by, its time to go. But the more stubborn of us are bound to challenge that and ask : "Really?"

Leaving out any religious connotations, I'm convinced by the fact that if you hold yours or someone else's life in your hands, and if you choose to rule out common sense and smart thinking in favor of stupidity or negligence, then its more likely that you or the other party is at higher priority on death's list. In this case, the 18 year old driver who handled the pickup probably made some poor driving judgments that took the life of the 12 year old boy, who also decided (or maybe even taught to do) that day that he would avoid wearing a helmet and take some risks.

On a third level are the noble folks who build structurally unsound products that don't function when they are called to do so. I have nothing to say to these people if they don't realize the damage they're doing, but hey...that's for another topic another day.

Over the years, the above 3 elements have finger pointed at each other whenever a traffic related issue came up. Drivers complain about stupid cyclists, cyclists complain about stupid drivers, and both of them complain about stupid cars, stupid bikes, stupid helmets and why, even stupid transportation laws and politicians. I am sorry to say that I'm ashamed of all three parties! Human tendency is to always hold self righteousness high and pass the soup bowl of blame to someone else, or provide an excuse for stupidity. If only one of the three could have done the right thing themselves, and followed the rules, or made life easier for the rest and lived and let lived, or did something like they said they would do, then we could be a more safe and constructive society.

Accidents can be avoided. Injuries can be prevented. Even wearing a helmet may not prevent the accident, but just like entering a lottery increases your odds of winning by a huge margin than your neighbor who didn't (probability of winning by not entering is a big zero), wearing a helmet increases the odds of preventing critical head injuries that could otherwise rob the quality of your life pretty quickly. [See Brain Injury Library, TBI Consulting]

1. STATISCULATION

The cabal of cyclists who don't support the wearing of helmets always have some excuse to make. Fine. If you don't like them, that's your choice. But by choosing to do so, you're agreeing to taking a huge risk with your critical 3 pound brain, your skin, your bones, the value of your life and that of your family's.

But there's one interesting thing here. To make their case loud and clear, they do some sketchy things. Among them is pulling up statistics from heaven knows where that show the growth of some negative events for cycling and attribute those events to some form of helmet law. The event can be anything from the decrease of cyclist numbers on the road to the increase in head injuries.

How they come up with this definitive correlation is not explained to the rest of us. What matters to them is that it correlated, somehow. Finally they come to the wonderful conclusion that helmet laws are indeed responsible for decreasing cycling. Or that helmets actually increase the rate of head injuries.

But for every explanation, there are alternative ways to think. For instance, in the first scenario, did wearing helmets really decrease cycling or did cyclists just stop riding, having found something better to do with their time and money? In the second scenario, did helmets increase the rate of head injury or did cyclists ride more faster (due to the false sense of security) and push the helmet they were wearing beyond design conditions for which it was made?

Oops. Didn't think of those, did you?

Sadly, in the age of the internet, we don't have too much of information anymore. We have too much of mis-information. Mis-information is spread by people who have more time to waste than the person willing to read and agree to them.

Be careful with statistics and spurious looking "graphs". At best, they can help understand a trend and simplify this complex world we live in. At worst, they can be employed by the person creating and using them to deliberately tie in two unrelated events and LIE. When they are presented to the rest of the world, the flu is passed around. Misleading people with the use of statistics is called Statisculation. The people most likely to be misled/awestruck are the ignorant who don't give a damn how statistics work or how the figures presented to them were arrived at. If they have a thought process to begin with that they absolutely stand by, and if they find any 'statistic' that will support that thought process, they will welcome it by all means and pass it onto others. [See How Statistics Can Lie, United States Golf Association]

CASE-STUDY : DID THE HELMET LEGISLATION REALLY DECREASE CYCLING IN AUSTRALIA AND LEAD TO OBESITY?

JACOBSEN'S FIRST FORMAL ANALYSIS OF THE SAFETY PRINCIPLE : In 2003, in a paper written for Injury Prevention, P L Jacobsen famously validated the "Safety In Numbers" principle, a well known concept in transport circles. The paper proved this principle by using census data to show that the likelihood of a collision between motorists and cyclists in many Californian cities decreased as the numbers of cyclists and pedestrians increased (inverse proportionality). This principle was represented by his exponential growth equation relating "relative risk of cycling" with the "amount of cycling". If cycling doubled, he said, the risk per km falls by 34% according to his exponential relationship. You can read the original paper here [Free, PDF].

D. ROBINSON'S RESEARCH TO VALIDATE JACOBSEN : On the other end of the globe in Australia, D. Robinson, a researcher from University of New England in New South Wales, tried to replicate and validate Jacobsen's safety principle. In 1990, a mandatory helmet law was passed in Australia, making it the first in the world to do so. Robinson sought to also find out if there was any correlation between the injury rates as reported by hospitals prior to and after 1990 (year of helmet law), compared with the number of cyclists on the road in the same time periods. She chose localized areas in Australia for this reporting, as opposed to several cities and communities that would make up the continent. You can read the original paper here [Free, PDF]

BEFORE THE HELMET LAW WAS PASSED : Robinson reported that cycling dramatically gained popularity in WA in the 1980's and as a result, cycling became more safer because the number of cyclists being admitted to hospitals decreased as per information from WA Health Department! Between 1982 and 1989, number of regular cyclists on the roads doubled. Take note that Robinson defines a "regular" cyclist as anyone who cycled at least once every week. The number of injuries and deaths per 10,000 cyclists decreased from 5.6 in 1982 to 3.8 in 1989, a 32.14% decrease. She rounded that to 33%, and finally concluded that it is consistent with Jacobsen's growth rule which states that if cycling ever doubles, the risk per km falls by 34%.

ESTIMATIONS WERE USED : Australia did not have data on bicycle use for these years. So Robinson used "estimates" that she borrowed from the Australian Bureau of Statistics for 1982, 1986 and 1989. The amount of error in these estimations are unknown and how they were estimated is also largely upto the guessing of the reader of the paper. If the estimations had error in them, we might as well find that the number of cyclists didn't increase, but they fluctuated or stayed somewhat constant in that time frame. In that case, the data wouldn't really validate the Jacobsen's growth principle for Australia or the rest of her theory that is to follow.

ROAD VEHICLE TREND? What gets cloudy here is that she does not show how the trend of motor vehicles on the road varied in this time frame. Suppose the number of motor vehicles decreased (due to population migration, motorists choosing biking instead of driving, or other reasons) then logically, that reason could also be attributed to the lesser number of fatal injuries in cyclists. No data of number of vehicles and the trends in their use during these years in WA has been provided to us.

AFTER THE HELMET LAW WAS PASSED : Robinson reported that certain "surveys" showed cycling had decreased in the years following the legislation year of 1990. The graph on the right side is extremely unreadable, as obtained from the original paper, so I've obtained a better one from a primary source that Robinson cited in her references. This primary source happens to be a 1995 paper from Monash University by Carr et. al which I will discuss a little below. You can access the paper here here [Free, PDF].

WHAT SURVEYS? : What the source "surveys" were, we not told explicitly. It is often assumed by many people that somehow surveys provide accurate information. But are they really scientific? How can you remove biases and the tendency to report wrong beliefs like we often see in surveys? What is the amount of error in these surveys? What is its confidence rate in %? Afterall, robots aren't behind surveys. Humans are. Also, if census data was used to distill the details of how much people were using their bicycle, the amount and frequency of data collection always has limitations. A census may take place infrequently (every 5 or 10 years) and it also may not yield comprehensive data about bicycle use by the population.

SMALL DATA SAMPLES : Even if the surveys were well documented and have 90% confidence , they reported on a small sample set for Melbourne, Victoria for the years 1987 to 1992. The number of years in that sample after the legislation was passed is a mere 2. It is not for the whole of Australia either. It is for Melbourne, Victoria. More importantly, the counting of cyclists was done in the same month (May) between 1990-92. What about the rest of months? Did the count decrease or increase? People may have different agendas from the May of one year compared to the May of the other year. Some may just be late to get on the bike due to being busy with other engagements. Robinson's data does not explore the cycling trend in those other months.

THE CYCLING TRENDS BETWEEN 1990-92: Now for years 1990-92, for the month of May, the decrease is not so dramatic as shown by Table 2. More cyclists were wearing helmets and the number of cyclists counted decreased in the first year and then rose again in the next if you check the numbers. Going by Robinson's numbers for adult cyclists, there was a 29% decrease change in cycling counts in 1991 from 1990, after the helmet legislation. However, in 1992, there was a 34% increase change in adult cycling counts from 1991. The levels had almost returned back to 1990 levels. Robinson doesn't delve into this too much, but still diverts the reader's attention to decrease in child cyclists and injuries.

DEDICATION OF CHILD CYCLISTS VS ADULT CYCLISTS : We all know that children are fickle minded. As they grow up, or due to some form or another of peer or parental pressure, their interests and hobbies and life goals change. Pretty darn quick. Children also could have been discouraged of cycling not because of helmet laws, but due to the fact that the helmets they were now required to wear by law were DORKY LOOKING, uncool, user unfriendly, or plain ugly to show around in public. I'm very much interested to see a sample helmet from 1990 in Australia and what kids thought about it THEN. Was there a survey of that?? Robinson does not go deep into this very important issue at all. But she's quick to take the naked numbers of decrease in child cyclists and point fingers at helmet laws. It is adult cyclists who are the dedicated ones. They have to go to work, and if that is to be done by riding a bike, they'll do it because they're the ones to put food on the table, not their kids. In the year following helmet law in 1990, according to table 2, the decrease in adult cyclists was lesser than the decrease in number of child cyclists compared to 1990 (-461 adult to -649 child, 1991) . In 1992, the increase in number of adult cyclists from 1991 was more than those of child cyclists (+378 adult to +89 child, 1992). As one can see, child cycling never recovered properly in that year compared to adult cycling. Robinson really didn't question this and find out WHY? She just quickly moves on to prove her big theory.

ROBINSON'S LOGIC : From the data in the table above, Robinson's logic is that the increases in numbers wearing helmets were "generally" less than decreases in numbers counted...which led her to write that this proves non-helmeted cyclists are more likely to be discouraged to wear helmets and continue cycling.

Wow. Wait a minute.

How can she relate 'discouragement' in Australian cycling with numbers for a small sample set of 30 days for 2 years for Melbourne, Victoria?? I can't understand that logic. Also, the more dedicated of cyclists are in the adult population, not in children. The decrease in child cyclists was more than that of adults.

SEASONAL VARIATIONS UNACCOUNTED FOR : The data also doesn't account for seasonal variations in cycling precisely because it investigated only the month of May. We all know that cycling is a seasonal activity. Only few are brave to venture out in winter in the elements. Victoria has a winter season. People ski there on its slopes, among other activities. Melbourne is colder than other mainland Australian state capital cities in the winter. More commonly, Melbourne experiences frost and fog in winter. Also looking at a climate chart from the Bureau of Meteorology, the month of May is one of the coldest in Melbourne, with temperatures ranging between a low of 9 deg C to a high of 17 deg C.

PRE-MODIFIED 8 YEAR HOSPITAL ADMISSIONS DATA (June, 1986 - June, 1994) : This comes from the Monash University citation that Robinson provided in her paper. The original data from hospitals for cyclist head injuries showed a decrease after 1990 but a sudden increase in 1993 and it was determined by "examiners" that this apparent increase was due to some "Casemix" anomaly in the Victorian Hospital System (increased admissions from hospitals because of the promise of more hospital funding from the government that year). So anyway, the original Hospital Admissions data for head injuries for cyclists was then modified through some sophisticated "multi-variate time-series modeling techniques" that even I have a hard time researching what they exactly did to the data. Anyone who didn't complete a sophisticated course in statistics can really bite the dust here.

MODIFIED 8 YEAR HOSPITAL ADMISSIONS DATA WITH MULTI-VARIATE TIME SERIES ANALYSIS : The modified graph after they applied their time-model to it just surprised me. Observe the lessened curve in helmeted cyclist head injuries after 1990 as shown by dotted line, compared to the solid lines that show the same before the model was applied. Again, the original data was modified through sophisticated statistical methods that only the researchers know exactly. Anyone has to seriously question the validity of these 'intervention analysis' techniques employed by different groups of researchers and understand it thoroughly before taking it, misplacing it and chanting slogans with it. At this point, I challenge all the people who decry the use of helmets : Do you fully understand these type of sophisticated statistical tools that researchers use to modify and play around with data? Do you understand the complex decisions that are behind these actions? Can you blindly say yes, before you've done your research and link to these articles to support your cause? A course in Time Series Analysis to fully understand what the Monash researchers have done in this paper requires atleast a semester or two of university-level study. This isn't the introductory level statistics that you do in your biology class.

The modified hospital data looked encouraging for cycling than the original. It was estimated from these modified data that in the first four years of helmet legislation, a 39.5% reduction in the number of head injuries was observed in Victoria(level shift). I presume that is what this graph shows. However, in comes at group of Australian researchers - Cameron et al, Mead et. al etc - who suggests that hey, the decrease in head injuries is dramatic compared to pre-law levels and then declare that this decrease MAY have been due an overall decrease in bicycle use, and not helmet use at all. Infact this has been suggested in Page 1 of the Monash report.

CONFLICTING RESEARCH CONCLUSIONS/SUGGESTIONS : Interestingly, in page 21 of the Monash report, there's evidence of some conflicting statements. They say their analysis is insufficient in distinguishing between reductions due to helmet wearing and reductions solely due to the possible reductions in exposure, and then boldly go on to say a little later that they think "its fair to assume" from their analysis that helmet legislation and the subsequent discouragement in cycling caused the decrease in head injuries that they "modeled" all this time. So what's the correct and final story on this one?

If you also didn't read between the lines of the report, page 15 says that the researchers didn't even investigate other measures of road safety in their models which may explain what happened to the decrease in head injuries to cyclists. How safe is this ignorance?

The rest of the paper from Robinson, which referenced the Monash paper for food, delves into injury rates for Victoria and finally concludes that : "Thus, as predicted by the growth rule, the risk of injury per cyclist increased when cycling decreased because of helmet laws in Australia."

Robinson's paper provides an inadequate picture of what really happened to cycling in the months after the helmet legislation in Australia. More so, one of the prominent references from Monash University she's given in her citation (Carr et al) use murky modeling techniques to modify original data, (which needs deep and further study). They also seem to be inadequate in their research as reported by themselves and make conflicting statements in several pages of their report, yet they say its "fair to assume" that helmet legislation decreased cycling numbers and hence cycling head injuries.

Robinson uses all this to do too much generalizing. She uses small sample sets, and data for localized regions in Australia (possibly from other researchers) to arrive at the grand conclusion that because the helmet law was passed in 1990, cycling collectively decreased in Australia in years thereafter! I may agree with the fact that there is safety in numbers but I cannot validate this paper to make a conclusion that helmet laws decreased cycling in Australia and dramatically increased the risk of injury just due to it. The trends for cycling that Robinson has reported is episodic and localized, and I would encourage her to investigate the effects of cycling over a long period of time and in many different places, at the same time, also delving into some of the other causes, apart from helmet law, that affected the numbers. I highlighted some of these possible causes in the writeup. It doesn't hurt to sometimes ask "WHY", even more than once.

Without giving a picture of all the factors mentioned above and their relative contributions to Australian cycling, no intelligent person reading Robinson's paper can accurately put faith in the fact that helmet law was the prime motivator for a long term, permanent, and nation wide cycling decrease in Australia. I urge her and the umpteen groups of researchers who have all fed on each other's research material to give these old papers a good second look. Continue to explore alternative explanations for a decrease in cycling levels. See if they are accurate, and still really relevant for 2009.

These are the papers that are being used to bring down safety laws in several countries of the world. I'm not even sure that the people who reference this material fully understand the use of your sophisticated statistical analysis techniques, and data manipulation tools and the implications of these actions.

PASS IT ON, BUDDY!

Many different websites, bloggers, forum participators and "medical experts" link directly to cycle-helmets.com, a website which makes it own interpretations based on Robinson and other Australian papers. Then they twist it to their liking and start throwing the bombs. Like this misinformation, portraying helmet laws as fighting with public health :

Most people who read this would not have read the original research papers but will assimilate other people's wrong interpretations of it and finally, what they'll receive, believe in and spread out to others are false assertions such as "helmets decrease cycling", or "helmets cause more injuries" or "helmets decrease public health" and so on and so forth.

If Australia has an obesity problem, does it really have to do a lot with "punishing" helmet laws or more to do with laziness of people (an age old problem, even before helmet laws), personality and psychological issues, and the human desire to put in more calories into the body than what is burnt. There is a definite science behind obesity and understanding it will help solve problems. Does the author of cycle-helmets really believe that there is some sort of major underworld partnership going on between obesity in Australia and bicycle helmet legislation?

Many other sections of cycle-helmets.com contain mis-information through videos. My favorite one was the following below, a link to a video showing a car running over a helmet, as if suggesting to the reader that a helmet should be somehow designed with super powers to withstand the weight and force of a car over your head.

Oh, and if it breaks, it must be a worthless piece of junk right?

Websites like cycle-helmets.com are easily visited by people because of its suggestive URL. Any one trying to do an internet search for cycle helmets will be caught unwary and visit the link. Then they'll be pulled into reading some fantastic BS on the drawbacks of helmets, helmet laws and how it brought down the entire continent of Australia and continues to do so.

Choose wisely what you read. Scrutinize everything, especially research papers. Case in point : After multiple peer reviews, Ed Coyle's research study on Lance Armstrong (Improved muscular efficiency displayed as Tour de France champion matures, 2005) which tried to show how Armstrong's body became more efficient between 1993 and 1999, was found to have some glaring calculation errors in the delta efficiency. [See Coyle Study on Armstrong : A Minor Error Or Scientific Hoax?] Ofcourse, Lance will not talk about this on his Twitter page. He may not even understand how the numbers were arrived at.

2. SPORTING PREJUDICE

Taking the example above of the "helmet laws & decreasing cyclists" correlation, it could very well be that the number of people cycling decreased because some of them discovered another sport and chose to commit to that over biking. I'm not saying that's exactly true, but what if it were? The question to ask then is : Is cycling the only way to keep fit?

If a person wants to be healthy and lead a better life, cycling is not the only avenue. If he got discouraged in cycling because of the need to wear helmets, he may not necessarily have gone back to drinking and smoking and sitting on the couch watching football all day. Unless you can prove that, this argument has no weight in it.

As cyclists, we all love to support our cause and make ridership grow. No harm in that. But healthy living comes in many forms. Bicycling is a solution. But its not THE solution. You can walk to work, golf, or play tennis on weekends, or even chill out in the swimming pool. Why the heck do you have to ride a bike to remain fit? Is it the only sport around? Please stop the desire to homogenize sporting and let people be themselves. Embrace your hobby and talk about it, but learn to shut up and let people do their own thing. Simple. Lately, pushing has come to shoving to make people ride more. I do not approve of this behavior, either from cyclists, advocates, or public health politicians. Promote all healthy ways of living, don't bias yourself to one.

CASE-STUDY : DOES LACK OF CYCLING SUDDENLY CAUSE DISEASE?

In a letter to the editor of the Canadian Family Physician, Thomas DeMarco MD argues that helmet legislation could decrease cycling. In his writeup, he references an Australian experiment with helmet law and connects it to the falling in ridership. We already covered the Australian Helmet Law crisis above and the flaws in a prominent research paper. But the citation given here is some 'C. Komanoff' who read 'some data' from a so-called 'Monash University' at some 'pro bike conference' in Ore, 1994. Great. What the heck is that 'data'? We won't know.

NO CYCLING = DISEASE ARGUMENT : In the following lines, he emphasizes that "most importantly, less cycling means less physical activity which translates to more atherosclerosis, obesity, non-insulin dependent diabetes mellitus and osteoporosis." Wow! Thats a big bunch of disease. How did Mr. DeMarco arrive exactly at the definitive correlation? No cycling = disease? And did he begin with the false thinking that cycling is the only sport, past time or recreation around, or that people who don't commit to cycling suddenly commit to physical inactivity in an instant, which inturn gets them sick and about to die? Can you please prove that?

IS CYCLING THE ONLY WAY TO STAY HEALTHY? What gives Thomas DeMarco the monopoly to generalize the human mind and the complex wants and desires of people? Or ignore other sports that can help one stay healthy? Most importantly, what gives cycling the monopoly to make people healthy? If this was the only way to be fit, we'd imagine a health fanatic world full of cyclists. That's not the case.

I, for one, am thankful that cycling is not the only sport/recreation around. I'd go beserk, otherwise.

CONCLUSION

The more I think about people complaining over helmets or helmet laws, the more I feel that they just care about the advance of their dogmas to others. They don't really care for their safety first and foremost. They don't think about the situation and environment they're cycling in (Europe is very different from America, where the status quo is motorship), and for them, the sport of cycling is the only salvation to a better life. If helmet laws are passed, they say that it will quickly bring down the numbers of cyclists on the road by quoting and data mining from questionable research articles and surveys done in other countries in different time periods. Then they argue that if ridership decreases, the number of people with AIDS, malaria, obesity, osteopororis, diabetes, blood pressure, cancer and any other ailment that you can think of will INCREASE. And we are to believe that.

False interpretations of statistics, or statisculation, and making absolutely baseless correlations between two unrelated events have been the defacto tools for these groups of people to fight helmet laws.

Yet, given all this, you oddballs may still opt to rule out helmets and decry the need for safety to ride the way you feel is best. Which is absolutely fine, as long as you don't mis-inform others, while forgetting the personal risks of going riding without a helmet.

But there could be a point when you arrive at the cross-roads. Say it was a Monday morning and you see your 12 year old kid, your own life and blood, walk out of the house with a bicycle. He's going to ride beside the road to get to school, which is about a mile away. He's not wearing a helmet. (At least that's what he learnt from the family growing up).

In a chilling moment a few hours later, the telephone rings at your house and the local cops have some life changing news for you and your wife. Its very distressing and there are no words to describe that sinking feeling. They happened to bring some really bad news about your son. He was riding his bike to school but apparently... he never made it there. They are requesting you at the scene immediately. Suddenly when your world was going all smoothly, someone in your family has become a statistic.

What will your line of thinking be then? I'm just curious.

ADDITIONAL/RELATED RESOURCES :

How A Bicycle Helmet Works

How Bicycle Helmets Are Made

Helmets : How They Work And What They Do

The Effectiveness Of Bicycle Helmets : A Review by Dr. Michael Henderson, who is a physician who has spent most of his professional life in highway safety research and administration. He established and ran Australia's first government crash research group and test lab, and he chaired the Standards Australia committee that wrote the first standard covering bicycle helmets.

How Helmets Are Tested In Snell Labs

Damned Lies And Statistics : Untangling Numbers From The Media, Politicians And Activists

Brain Injury Resource Center

What's Your Excuse, Washington City Paper (March 11, 2009)

Bicycle Accident Victim, 12, loved the outdoors

Current U.S Bicycle Helmet Laws

Continuing Misinformation About Declining Hunter Numbers

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10 Design Case Study : Thomson Elite Seatpost

Readers will remember that a couple of days back, I ran a controversial story of a Thomson Elite seatpost that broke off at one of the bolting ears due to a "fall". I placed known marketing information about the product alongside the given failure situation. Why some readers were irked is hardly surprising, since the Elite is widely considered as one of the best designs in the market. For many, it has provided years of faithful service.

Did you know that the Elite seatpost has an elliptical bore?

So what has made this seat post so popular? It must be in the design, right? Please see the latest update to my previous post. I go through most of the design features of the seat post and comment on its attributes with the help of high resolution photos. I also run through the product manual and high light some of the factual installation warnings that Thomson has made clear pretty upfront. A seat post failure while riding can be absolutely dangerous, no question about that. Hence, installation directions and warnings cannot be taken for granted and ignored however mundane reading them maybe.

See you there.

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11 EE-yikes : 5 Pivot Brakes, Modulation, Cost

"The real question is, 'Does the design work really work?'. The short answer, “OH YA!” The wide stance and vise like look of the eebrake translates directly into outstanding braking performance. Optimized leverage and modulation is realized through our multiple lever system. Our efficient structure does this all with a minimum weight; less than 200 grams per complete brake set with pads."

- EE Brakes

With the economy in shambles, and people trying to be more conservative with their money, here's a party launching out another 500 dollar brake set to market. Whats wrong with cycling?

The new 5 pivot EE brake is sure to polarize. They are ornately crafted, and on the surface, there seems be be some real work that has been put into them. In this age of KISS (keep it simple, stupid), you may have to like steam locomotives or complicated medieval torture devices to comfortably find pleasure in this creature.

However, for their steep asking price, their website was choke full of marketing hoopla and devoid of useful information. A cautious/intelligent consumer wanting to know how on earth their 'multiple lever system' generates better modulation than what was previously realized is left with little but a colorful picture of an FEA screenshot that's too small and blurry to even understand.

That is a little substandard.

If you want someone to part with their precious coin in your favor, your first rule of thumb is to give them a good reason 'why'!! Words like "bigger", "super stiff", "beefy", "pure awesomeness" etc are a tad bit overdone these days to lure someone to purchase.

So in my honest opinion, you're missing the beat. Since your design is unique, it opens itself to serious scrutiny. I suggest you consider writing a white paper on the brakes and posting it on your website so as to back up bold claims. How do your brakes work and how is modulation enhanced compared to the best dual pivot offerings? I certainly cannot see how. Give us a free body diagram of multiple leverage action. Is the mechanical advantage constant? Is the brake behavior linear or non-linear? Explain briefly the FEA involved. Pictures don't make sense if you can't read them! And if you have testing done, show us some numbers from the setup runs. This is good, and proper engineering practice.

This way, we'll hope to arrive at a conclusion as to what those extra dollars/gram is doing. Are they :

A) Affording one comfort and peace of mind in installation/adjustments and superior performance exactly as promised at the brake end?

OR

B) Just a feeling of psychological advantage of possessing a lightweight product, which is then quickly canceled out by application inconvenience through over-complication?

EE Brake installation must be meticulous and doubles the time required for simpler designs. This reviewer showed a picture of sand and grime in the linkages, and reported a nasty-sounding “crunch” when the brakes were used in wet weather (5 pivot means 3 additional crunches than dual pivot).


FEA snapshot. Good looking but deliverables are zero.

A clipping of the sequence of steps involved in installation. A mechanically disinclined person might need a fair amount of coffee to get through this successfully.

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64 Thomson Elite Seatpost Failure

BOLTING EAR FAILURE ON IMPACT

Despite all the reputation that Thomson has in making reliable cycling components and giving the best cushions against catastrophic failures on impact, this person's Elite seatpost (in particular, one of the bolting ears that stick out sideways ) broke off like chalk piece after a fall. The bike was leaned on a wall when it tipped over and fell sideways. Hence, the owner was apparently not even seated on the bike at the time of impact. The seatpost ear broke as he straightened the bike and it dropped in his hand. You can read some back and forth question/answers between me and the owner of the post as you scroll down. That will give some background information into the incident.

Courtesy : Khabar Bike

Compare this to Thomson's marketing literature online. Among several other things, the company happens to generously regard itself as producing the only seatpost in the market incorporating a "bending fuse" against catastrophic failure.

Their website says :

"The Thomson seatpost design incorporates a bending fuse to prevent catastrophic failure. All brand-x seatposts we tested - every one of them - failed in catastrophic failure with the seat and clamp components - and sometimes pieces of the tube and head - flying off in all directions. This type of failure would dump the rider."

And something about impact absorbing clamps :

"Impact absorbing clamps - clamps, head, and assembly will spread and flex on impact to protect seat, rails, seatpost and rider. Easy on seats - allows seat to survive heavy impact loads without bending rails."

The owner of the seatpost, however, had a contrasting experience. He wrote on his blog after the incident :

"Forget the hype! Despite the claim that their seatposts are over "40% stronger" on ultimate strength test than the strongest production seatposts on the market, the Thomson Elite seatpost is not tough enough to withstand even a simple fall. And here's proof of that! This four-year-old post on my GT broke in the upper tube area, which is apparently 'strong enough to withstand 350 foot-lbs of torque', when the bike took a tumble sideways while it was stationary. It didn't "bend slightly" on impact like what the Thomson folks had you believe would happen but just crumbled like a cookie at the top. Actually, the OEM seatpost that I was using before I got the Thomson in a moment of weight-weenie lunacy seemed to take much harder knocks! And it looks like it could take plenty more! So, if you've got an Elite seatpost on your bike, watch out mate! It could be a disaster waiting to happen. "

I'm not sure what went wrong at Thomson's end to cause the seatpost to be brittle, but I'm just going to have to drop this one in the "Marketing Mishaps" section for now. This doesn't mean your Elite seatpost has the same problem. But it won't hurt to be informed. Out of 1000 apples, its likely that 2 end up being bad and that's the nature of manufacturing. When those bad apples that dont meet the standards turn into the customer's hands, that's where the issue reveals its uglier side. If Thomson stands by their word, they should delve into this incident and redress the issue (i.e If they are responsible. Corrosion, or user over tightening cannot be ruled out at this stage).

Take note that the lighter weight Masterpiece seatpost is essentially a machined out Elite. Also note that I suspect some of the brittleness MAY be caused due to anodizing, since the anodized Aluminum Oxide on the surface of the substrate is pretty brittle, even though hard. When the part elastically deforms, the oxide layers starts cracking and it propagates down into the substrate metal. This will only reduce the part's fatigue strength. [Source : Aluminum And Aluminum Alloys by J.R Davis & Associates (ASM)]

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UPDATE March 19 12:00 pm

A CONVERSATION WITH THE USER OF THE SEAT POST

TO THE BLOGGER OF KHABAR BIKE (and user of the seat post) :


Due to the number of requests I'm getting to dig further into this issue, I have to put you in the spot light by flexing my Bee Muscles (crunnch). Please tell us the following if you don't mind :


1) Did you over tighten the seat clamp outside limiting values specified in the product sheet?

Khabar Bike : Not as far as I'm aware of. And it's been untouched since I last changed out the saddle about a year ago.


2) Did you wash the seat post a number of times without letting drying it out? Or have you used the bike a good number of times in the rain?

Khabar Bike : Definitely not. And I hate riding in the rain.


3) Is this the first time that the seatpost fell, taking a hit on the same area on the post in question?

Khabar Bike : Yes, as far as I can remember. And this is the first time I've ever had a broken seapost in the 12 years I've been a serious bike buff, with seven bikes including a lugged steel Pinarello, an old Trek bonded/carbon road bike and a 12-year-old Gary Fisher hardtail. They have a Syncros, ITM or OEM seatpost.


4) Did you buy the post from a recognized Thomson dealer? Brick and mortar shop? Online? Ebay? The possibility of a knock-off cannot be ruled out.

Khabar Bike : Yes. My LBS is one of the most reputable in the area. And the seatpost (paid about $70 for it) came with Thomson's unique but pretty useless bag and folded manual. I also have another Thomson seatpost (with layback), on my hardtail, which has been holding up fine for more than three years.


5) Pretty Useless Bag... the manual was in this useless bag. Did you read it?

Khabar Bike : Yes, I did and didn't find it useless at all.

6) Do you recall how the bike fell (orientation)?

Khabar Bike : It fell sideways. I picked it up by handlebar and the saddle and the back part broke off in my left hand.

7) Were you riding it when this happened (added weight) or did it free fall as it tipped over (just the bike weight)?

Khabar Bike : It was leaning against the wall when it tipped over.

8) Did the seatpost also have the saddle attached during that time?

Khabar Bike : Yes, the clamp was secure and undamaged, and still attached to the saddle.

Finally, I'd just like to say that I'm not as upset about the whole thing as I would've been a few years back when I was really into lightweight products. These days, anything that doesn't cost and arm and a leg and lasts is just fine with me.

Thank you.

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UPDATE March 25


DESIGN FEATURES OF THOMSON ELITE SEATPOST.

THIS IS A WELL REGARDED SEAT POST AND MANY CONSIDER IT TO BE AMONG THE BEST DESIGNS.

KNOWN FACTS ARE GIVEN IN BLUE FONT. ANY EXTERNAL REFERENCES TO LINKS ARE IN RED.

This is the patent for the Thomson seatpost in question. The patent is titled "Lightweight High Strength Bicycle Seat Post And Associated Clamp Including Seat Angle Indicating Indicia". The main idea behind the intention was to provide a lightweight, strong seat post that has a wide range of adjustment and adequate cushion against catastophic failure.

The product is made from a 7000 series (Zn added) Al alloy and marketing materials claim that it is "40% stronger in ultimate strength tests, and has twice the fatigue life of 75 of the most strongest production seat posts on the market." The post also seems to have what is an obvious anodized black finish.

According to Thomson : "The head is not pressed or bonded in. This allows for superior strength and minimum weight, allowing higher strength at low weights."

One of the apparent design goals was to make this seat post able to withstand 350 in. lbs of torque, with bending taking place at 250 in. lbs of torque. There appears to be shoulder fillet at the tube-head interface (machined). The bigger the fillet radius, the more the stress concentration factor is reduced. Thomson designers should have selected the fillet radius for a desired stress concentration factor for this shaft for the particular loading case (torsion, tension, bending etc). The critical numbers here are the D/d ratio and the r/d ratio which can be referenced to known and published charts to find the stress concentration factor (you can work backwards in design as well). See Peterson's Stress Concentration Factors by Walter Pilkey for more information.

When you first feel the seatpost in your hand, you'll come across the sharp features at the sides of the head. At the edges as shown, chamfer radii appear to be very small, hardly noticeable. See picture below.

This isn't a circular cross-section, as you can see. Thomson says : "Natural ellipse bore inside tube for optimum strength to weight ratio." The thickness is higher on the front and rear end of the seat post, corresponding with the directions of the bolt locations on the head above it.

Moment of Inertia (or Second Moment of Area) of a hollow elliptical section beam about a horizontal axis passing through the center of gravity. Practically, it is the measure of the capacity of a cross-section to resist bending. See The Design Of Structures By Samuel Anglin, C.E

The same for a circular hollow cross section

If you look carefully to the tube body section under the light close to the logo, you'll see some fine marks/grooves that extends throughout the length of the tube. Is this a deliberate feature to prevent slippage of the post when clamped at the seat tube? Its pretty nice.

Here's the top and bottom clamp together with the swivel nuts inside. This arrangement on the tube supposedly allows the claim : "Infinite tilt adjustment minus 5° and plus 29°."


The product sheet says : "All Thomson seatposts are designed with positive metal to metal stops. These positive stops and bolt lengths are designed to work together to allow a maximum 5 upto 29 degree down tilt. This means the tilt adjustment of the clamps will be stopped by the positive stop before the back bolt runs out of the nut. This prevents damage to bolts, nuts, ears, and clamps that may otherwise occur with over adjustment."

On the product sheet, Thomson mentions very clearly : "Never tighten the front bolt hard against the positive stop. Make sure that bolts are tightened against each other. Always tighten the back bolt to 60 inch lbs of torque. If the front bolt is tightened hard against the front ear, the force created by that tightening will be subtracted from the bolt's available force to withstand high impact loads. If the front bolt is tightened hard against the stop and not against the rear bolt, the rear bolt could loosen during the impact loads."

Recommended torque values have been set in the product sheet to 60 inch lbs for each bolt.

A warning in the product sheet cautioning that if the clamp lip touches the tube, the seatpost could dimple during clamp tightening.

Another warning that post is for use with 7mm seatrails only.

Thomson says : "The Thomson seatpost design incorporates a bending fuse to prevent catastrophic failure. All brand-x seatposts we tested - every one of them - failed in catastrophic failure with the seat and clamp components - and sometimes pieces of the tube and head - flying off in all directions. This type of failure would dump the ride."

What stumps me is that for all that marketing on their website, there is actually no bending fuse description on the instruction sheet. I'd actually like to see a description of this and how it works. Is this incorporated into the top and bottom clamp design somehow, and not mentioned? What say, Thomson?

Finally, the highlight of the Thomson marketing is this statement :

"The Thomson seatpost has a clamp, head, and upper tube strong enough to withstand 350 foot-lbs of torque. The tube will start to yield and bend at the seat tube clamp at about 250 foot-lbs of torque. Remember all brand-x posts we tested flew apart at less than 150 foot-lbs of torque. Under severe impact the Thomson seatpost would bend slightly and allows the rider to come to a safe stop or finish the ride. The ride could continue."

My thoughts on this statement are that putting this alongside with what was actually observed by the user who broke his seat post (see top picture of failure), the tube did not withstand the force and there was no observation of bending. It appears that the impact forces approached ultimate strength for the broken area in question and broke catastrophically. It looks like the rider was not injured in any serious fashion.

What remains to be researched is how the bike with the seat post and saddle fell, validate the claims of the user (see above) when he replied that he did not overtighten any of the two bolts, validate the claims of the presence of a bending fuse and the actual strength of the product from the manufacturer, do a small paper and pencil analysis of the forces and stresses encountered and compare this with known the known design limits of the seat post.

The owner has made it known to us that for about a year, he did not have to change the saddle on the seat post. It is likely that during this time, he may have lost notice of the critical areas of the seat post. A stress riser may have led to the formation and propogation of a tiny crack, which, upon the post striking the ground in this fall, led to the severing of one of the bolting spots from the tube due to the torsional shear stresses encountered.


What was nice from writing this post so far has been the fact that this issue has been exposed to the world. Users must remain careful of how they install and use cycling products. At the same time, competition in the cycling industry is cutthroat. Over the years, we've seen an increasing number of bad designs with bold marketing claims and promises. Few have stood the test of time.

UPDATE APRIL 12, 2009

A reader notified me of another Thomson seatpost failure incident, only this time it was a setback post and the failure occurred on the post body itself, very close the bolting ears. These pictures were shown on Mtbr.com Forums, by user Apacherider. Incidents like these are not safe and opens up a range of possibilities for injury. Since the above incident and this new one is not very far apart in occurence date, Thomson must really dig into the backgrounds of the causes. It seems to me as if these posts are in need of more reinforcing in the areas around the bolting ears, including the ears themselves.

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