Category Archives: Helmets

Can helmets cause permanent disability?

In 1993, a team of researchers conducted lab experiments on bicycle helmets. The purpose was to measure the chin strap forces in accidents. The researchers were shocked by what they found. They found that helmets can seriously damage cyclists neck:

“The non-shell helmet did in all trials grab the asphalt surface, which rotated the head together with the helmet. The consequences were in addition to the rotating of the head, a heavily bent and compressed neck, transmitted on through the whole test dummy body after the impact.”

A related incident was reported in the New York Times:

“In August 1999, Philip Dunham, then 15, was riding his mountain bike in the Great Smoky Mountains National Park in North Carolina and went over a jump on a trail. As he did, his back tire kicked up, the bike flipped over and he landed on his head. The helmet he was wearing did not protect his neck; he was paralyzed from the neck down.

Two years later, Philip has regained enough movement and strength in his arms to use a manual wheelchair. He has also gained some perspective. With the helmet he felt protected enough to ride off-road on a challenging trail, in hindsight perhaps too safe.

”It didn’t cross my mind that this could happen,” said Philip, now 17. ”I definitely felt safe. I wouldn’t do something like that without a helmet.


Look at a bicycle helmet. It has been designed with comfort in mind. It is made of light weight material that grip the road on impact rather than glance off it (as is the case with motorcycle helmets).

The increase in the volume of the head, coupled with the gripping of the road surface, means that when a head comes into contact with the ground at speed, the head or body is rotated, sometimes snapping the spinal cord.

This is a dangerous aspect of cycling with a helmet. You run the risk of paraplegia or quadriplegia.

Bicycle helmets can get caught in accidents, damaging the neck, as reported in the Canberra Times:

“Lud Kerec was training for one of the toughest triathlon events in the world when he smashed head-on into another cyclist in the ACT’s north. …

”It is unlikely I’ll walk one day,” said the 65-year-old Mr Kerec, who takes half a cup of drugs a day. He was nearly garrotted by the strap from his own helmet after he believes it became tangled in the other bike and yanked his head back.”

In 2010, a helmeted cyclist died in Wanniassa (Australian Capital Territory). The pathologist’s report to the coroner shows that that he suffered diffuse axonal injury. Diffuse axonal injury is a severe type of brain injury aggravated by bicycle helmets.

These are not unique incidents. Many studies have reported increased neck injuries from bicycle helmets. For example, research by McDermott et al. (Trauma, 1993, p834-841) found 75% more neck injuries among helmet wearers.

Why don’t bicycle helmets have warnings about the risk of permanent disability while wearing them?
This is a serious risk that people should be aware of.

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US government drops claim that helmets reduce 85% of head injuries

The US government has dropped its claim that bicycle helmets reduce 85% of head injuries. The claim came from “research” conducted by helmet advocates in 1989. Many researchers have tried to replicate its results, but have been unable to do so. Amid severe criticism, the authors had to re-work their data, and arrived at a lower effectiveness rate.

This invalid claim is often quoted by people eager to push helmets. The US government had quoted the claim on its web site.

In 2013,  the US Department of Transportation agreed to delete the claim. This followed a petition lodged under the Federal Data Quality Act. The Data Quality Act requires information on federal web sites to be accurate and supported by appropriate research.

This was first reported by the Washington Area Bicyclsists Association. This followed its successful campaign against a bicycle helmet law in Maryland in early 2013.

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Helmet manufacturer ordered to pay $3 millions as compensation for brain injury

US helmet manufacturer Riddell had to pay US$3 millions in compensation to an injured football player. Rhett Ridolfi suffered severe brain damage, as well as paralysis, despite wearing a helmet. A Colorado jury found Riddell negligent in failing to warn players about concussion.

This is one of many lawsuits about brain injury while wearing a helmet. The injured person lawyer said:

“If they had told the truth, and said, ‘You have a 50 percent change of getting a concussion with this helmet,’ what mother or father would let their kid play football in a Riddell helmet? And you can still buy this helmet today.”

Helmets provide the illusion of protecting against brain injury. Helmets cannot protect against rotational acceleration, the principal cause of brain injury. Report from the Toronto Star:

“Increasingly, what helmets have become are talismans. Riddell (and every other manufacturer) understands that no space-age resin, no lightweight polymer, no amount of high-tech bafflegab is going to fully protect you if you nail something hard and fast at just the wrong angle. They manufacture the illusion of full protection …

What they’re selling is witchcraft. The fault here does not lie with the manufacturers. It lies somewhere within the culture. …

There is very little difference between wearing a helmet and wearing a piece of the true cross. Both are faith objects. The power of any talisman is that its protective aura is self-reinforcing. As long as you aren’t hurt while you’re wearing it, one presumes the talisman takes the credit. …

the surest way to protect against brain injury is to either engage in pastimes that
A) don’t require helmets or
B) have adapted themselves to relatively safe, helmetless participation. …

With the helmet goes a misplaced sense of invincibility.”

As Jerry Seinfield noted, a key issue is the culture surrounding helmets:

Bicycle helmets have the same deficiency. Additionally, they can increase brain injury:

“Protecting the brain from injury that results in death or chronic disablement provides the main motivation for wearing helmets. Their design has been driven by the development of synthetic polystyrene foams which can reduce the linear acceleration resulting from direct impact to the head, but scientific research shows that angular acceleration from oblique impulse is a more important cause of brain injury. Helmets are not tested for capacity to reduce it and, as Australian research first showed, they may increase it.“

Helmets have been promoted by claiming they protect against brain injury. This can lead to people overestimating their benefit, taking more risks. As reported in the New York Times:

“the increased use of bike helmets may have had an unintended consequence: riders may feel an inflated sense of security and take more risks. …

The helmet he was wearing did not protect his neck; he was paralyzed from the neck down. …

”It didn’t cross my mind that this could happen,” said Philip, now 17.

”I definitely felt safe. I wouldn’t do something like that without a helmet.” “

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Barefoot running and cycling

An interesting analogy between barefoot running and cycling:

For years it has been ingrained in to folk that go hill-walking that it
is *essential* to wear “stout footwear with proper ankle support”, with
the latter taken to mean a high lacing cuff and the phrase really
meaning big, stiff hiking boots.

In more recent times folk have started to realise that this is a lot of
tosh, and in fact the literature on foot injuries tells you
counter-intuitive things about how and when feet get injured (like more
often in shoes than barefoot). Such people have started taking to the
hills in sandals and trainers, realising that the human foot isn’t an
evolutionary misfire but is perfectly capable of looking after itself as
long as the user engages in the ancient Zen mind-trick known as “looking
where they’re going”.

But you tell this to the boot die-hards, and they look at the scuffs on
their dreadnoughts and say they prefer intact toes to bloody puddings on
the end of their feet, and how their boots have saved them from terrible
injury etc. etc.

I used to preach the gospel of Big Boots too, but entering a Mountain
Marathon had a curative effect. All these people doing this regularly,
faster and over rougher terrain than I usually do, and hardly a pair of
boots in sight, perhaps they know something I’ve not been accepting?
c.f. cycling trip in Amsterdam and helmets…

This analogy is from by Peter Clinch, from Dundee, Scotland.

I love this part:

the ancient Zen mind-trick known as “looking where they’re going”

This highlights the difference in philosophy between the two groups.

  1. One takes responsibility for being cautious enough to avoid injuries.
  2. The other relies on technology to compensate for higher risk taking.

The belief in the “protection” using shoes is like the belief in the “protection” using helmets:

  • Both appear to “protect”, even though they can result in increased injuries.
  • Both seem so “obvious” than few people question them.
  • Both are harmful in ways that are counter-intuitive.
  • Both have their strong advocates who show a religious faith in them.
  • Both induce a false sense of safety, resulting in increasing risk taking.

In cycling, as the shoulders are much wider than the head, most falls do not result in the head touching the ground. Should it happen, the scalp makes the head slide, reducing friction and rotation. This reduces the risk of brain injury through rotational acceleration.

With a helmet, the larger volume of the head makes it more likely for the head to hit the ground. The polystyrene helmet tends to stick to the road and increases rotational acceleration. This increases the risk of brain injury.

Is this “protection”?

We can be fooled into accepting “protective” equipment that is not necessary, and even harmful. After the helmet law in Australia, the risk of injury tripled.

Helmet manufacturers know how to exploit our fears using scaremongering advertising. It takes effort to escape such insidious influence.

Next time somebody peddles “safety” equipment, ask

  • Does the risks warrant the equipment?
  • Could the “safety” equipment do more harm than good?
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The surprising impact of helmets on safety


Contrary to popular belief, helmets main impact on safety has not been the protection they provide, but the increased in the risk of accident associated with them. Helmets protect, but not enough to compensate for the increased risk of accident.

Although the motivation for wearing a bicycle helmet is to reduce the risk of death & serious brain injury, the net result of imposing a helmet law has been to increase the risk of death & serious injury.


Two types of injuries

Broadly speaking, there are two types of injuries relevant to bicycle helmets:

  1. Minor injuries like bruises and lacerations to the skull.
  2. Severe injuries like brain injury, skull fractured, or neck injury that can lead to disability.
Bicycle helmets provide cushion against minor head injuries.  On hitting a flat surface, the polystyrene compresses to attenuate the impact.  However, in a serious impact, helmets tend to “fail”, or break into pieces, providing little protection.  A polystyrene based helmet is not designed to protect in a serious accident:

“In cases of high impact, such as most crashes that involve a motor vehicle, the initial forces absorbed by a cycle helmet before breaking are only a small part of the total force and the protection provided by a helmet is likely to be minimal in this context. In cases where serious injury is likely, the impact energy potentials are commonly of a level that would overwhelm even Grand Prix motor racing helmets. Cycle helmets provide best protection in situations involving simple, low-speed falls with no other party involved. They are unlikely to offer adequate protection in life-threatening situations.

A soft-shell helmet is a piece of polystyrene covered by a layer of plastic less than 1mm thick.  It can protect in a minor accident.  However, it is not designed to protect in a serious accident.
Helmets make little difference in a serious accident, as Dr Hooper reports:

“Looking at evidence, it does not matter if people are wearing a helmet or not, any serious accident on a bike is likely to kill them,”

Wearing a helmet can induce cyclists to take more risks, sometimes with serious consequences:

“the increased use of bike helmets may have had an unintended consequence: riders may feel an inflated sense of security and take more risks. …

The helmet he was wearing did not protect his neck; he was paralyzed from the neck down. …

”It didn’t cross my mind that this could happen,” said Philip, now 17. ”I definitely felt safe. I wouldn’t do something like that without a helmet.” ”

While helmets can reduce minor head injuries, they can also increase the risk of neck injury.  Contrary to popular belief, helmets are not designed to protect against severe brain injury, and may aggravate it some circumstances.

Yet most  helmet studies fail to distinguish between minor and sever injuries.  Minor and severe head injuries are lumped together into a category called “head injuries”. The much larger number of minor injuries masks the trend in severe injuries. An apparent reduction in minor head injuries can mask an increase in severe injuries.

What does the data tell us?

Relevant data that can shed some light on this issue comes from New South Wales (NSW), Australia. It includes minor injuries, separated as head injuries and non head-injuries, for child cyclists before and after the helmet law. It also includes data for death & serious injuries for child cyclists and pedestrians.

Before the helmet law, about 20% of cyclists wore helmets. After the helmet law, about 80% of cyclists wore helmets. To make sense of the data, it is worth keeping in mind two key factors affecting injuries:
  1. There were 40% fewer cyclists after the helmet law. The risk must be adjusted per cyclist.
  2. The helmet law was introduced at the same time as other road safety measures, like a crackdown on speeding and drink driving. Injuries declined significantly for pedestrians, who face a similar risk as cyclists, being hit by motorists. By adjusting for safety improvements observed with pedestrians, we can isolate the effect of external factors, so that we can better understand what can be genuinely attributed to helmets.

A detailed analysis of the data can be found here.  Additional injury data for pedestrians can be found here.  Here is a short summary of the analysis of the data:

  1. Compared to what would have been expected without the helmet law, the risk of non-head injury for cyclist almost doubled. This indicates that the risk of accident almost doubled. Explanations for the increase in accidents include risk compensation and safety in numbers.
  2. Compared to what would have been expected without the helmet law, the risk of death & serious injury increased by 57%. This indicates that helmets did protect against some serious injuries, but not enough to compensate for the rise in accidents.
  3. Compared to what would have been expected without the helmet law, the risk of head injuries for cyclists increased by 40%. This indicates the helmets were more effective at preventing minor injuries.


Compared to what would have been expected without the helmet law, the risk of accidents almost doubled, the risk of death & serious injury increased by 57%, and the risk of head injury increased by 40%.

The data indicates that bicycle helmets do protect, but not enough to compensate for the rise in accidents.

Accident avoidance vs protection

Although helmets do protect, they have not protected enough to compensate for the rise in accidents.  The net safety effect of imposing helmet has been to increase the risk of  injuries, both head-injuries and non-head injuries, and both minor and serious injuries.

However, the sharp increase in the risk of accident is the most significant impact of helmets on safety. Why wear a “safety device” that increases the risk of accident while failing to protect sufficiently to compensate for this increased risk of accident?

There is an odd discrepancy between the motivation for wearing bicycle helmets (to reduce the risk of death & chronic disability), and the actual result of the helmet law: a much higher risk of death & serious injury.

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Misguided doctors or marketing agents?


In the 1980′s, Bell, a helmet manufacturer, was keen to expand the market for bicycle helmets, its most profitable product. It approached the Snell foundation and offered funding for research on bicycle helmets. The Snell foundation chose avid helmet lobbyists to conduct this “research”.

The helmet lobbyists initial “research” claimed that helmets reduce 85% of head injuries. This claim is impossible due to inherent limitations of helmets. The authors had to re-work their data, and withdrew their claim.

The Snell foundation has kept funding these researchers. Boosted by the “research”, the market for bicycle helmets expanded. At $100 for a piece of polystyrene, the profits are huge. Helmets manufacturers have reinvested their profits into lobbying for helmet legislation. They sent executives all the way to Australia to lobby for a helmet law.

In 2013, the US government dropped its claim that helmets reduce 85% of head injuries. It first made the claim based on the research mentioned above, but then admitted that there was no credible basis for the claim.


The misleading “research”

A 1989 study on bicycle helmets claimed:

“we found that riders with helmets had an 85 percent reduction in their risk of head injury”

How can helmets reduce 85% of head injuries considering they don’t cover the face where 70% of head injuries are?

Injuries to the skull (the part of the body a helmet covers) constitute 10% of cycling injuries,
or 30% of what is usually classified as head injuries (including face injuries).

How did they arrive at such impossible claims?
They compared a helmeted group who rode supervised in parks with an un-helmeted group who rode unsupervised on busy roads. The difference between the two groups was attributed to helmets. They failed to consider confounding factors, a common error in statistics.

The study compared helmeted cyclists in bicycle paths with un-helmeted cyclists on roads. It attributed the difference to helmets.

This flawed study was widely criticized. It failed to select a representative control group. It misused the odds-ratio. It lacked serious injuries. It failed to adjust the results by age group.

As summarised in this review:

“The study compares groups of cyclists who chose to wear helmets with those who did not. Many variables, such as the reasons for wearing a helmet and attitudes to risk, were not controlled for by the researchers and may have influenced the results.”

The 85% figure is meaningless. It does not correspond to physical protection provided by helmets. It is the authors own generous estimate misrepresented as the result of their “study”. Many researchers have tried to replicate its results, but have been unable to do so. The authors had to re-work their data, and withdrew the claim.

The data from the study indicates that helmet wearers were 7 times more likely to have accidents. The study ignored this.

Instead of claiming
“Helmets protect x% of head injuries”
A more objective assessment would be:
“Helmets appear to protect against some head injuries. However, they are also associated with more accidents.  It is not clear whether there is a net safety benefit.”

This study was influential. Few questioned it, as they were eager to believe its claims. Despite the authors withdrawing the claim, it is still quoted as if it was true.

This research became a model for further “research” replicating its flaws and bias. Such research tends to jump to a predetermined conclusion. Such studies exaggerate the protection provided by helmets while ignoring the increase in accidents. The sheer volume of this “research” has misled the medical community.

The vested interests behind this “research”

In 1956, a racing driver called Peter Snell died from head injuries despite wearing a Bell helmet. His death to the creation of the Snell foundation. Since, Bell has developed a close relationship with the Snell foundation.

In the 1970′s, Bell introduced polystyrene bicycle helmets. They were not adopted by mainstream cyclists. In the 1980′s, Bell started to market bicycle helmets more aggressively. They became the most profitable range of helmets. In the mid 1980′s, Bell suggested that the Snell foundation should commission research into bicycle helmets, and provided funding to do so.

Snell chose 3 researchers to do the study, including Dr. Frederick Rivara. Dr. Rivara was a bicycle helmet advocate and an active helmet lobbyist. This was an odd choice. Helmet research conducted by helmet lobbyists was likely to be biased.

Snell requested that the study was

“done to demonstrate the effectiveness of bicycle helmets in reducing head injury”.

Note the assumption of effectiveness upfront instead of asking an open-ended question. The bias also came from the Snell foundation.

Using sponsored “research” to promote helmets and lobby for legislation

Bell used the commissioned study in its advertising:

Bell advertising, using the “study” it sponsored to claim that helmets prevent 85% of head injuries

Scaremongering is a key tactic. Parents are an easy target, scared into buy a product to protect their child from an exaggerated danger.

Bell then used this commissioned research to lobby governments to promote helmets. Lobbyists funded by Bell started to lobby for mandatory legislation. The commercial benefits of such legislation was clear to the helmet industry.

Bell funded organisations like SafeKids. This was shrewd, as it made it look like there was popular demand for helmet legislation. This lobbying resulted in mandatory helmet laws for children in various US jurisdictions.

A vice-president from Bell flew to Australia to attend EVERY mandatory helmet law hearing.

The market for helmets almost doubled between 1993 and 1995. This lead to record profits for Bell bicycle helmet division. In 1995, the bicycle helmet market was worth about $200 million dollars. Large profits could be re-invested into further lobbying and funding of “studies”.

Funding more research

The Snell Foundation has kept funding these researchers. In 1996, they published a study claiming:

“Bicycle helmets, regardless of type, provide substantial protection against head injuries for cyclists of all ages involved in crashes, including crashes involving motor vehicles.”

There was a failure to disclose conflicts of interests:

“This research was supported by a grant from the Snell Memorial Foundation, to which the principal bicycle helmet manufacturers are contributors.”

The study attracted much criticism. The authors again failed to consider confounding factors. They made more implausible claims.

Close analysis of their data indicates that:

“The data show that, apparently, the protective effect of a helmet increases with increasing severity of injury. It is extremely difficult to accept such a result, and indeed, it is the opposite of what is seen in population level studies, which return the more sensible outcome of declining protection with increasing severity of injury. It must be the case that confounding factors systematically caused non-helmeted cyclists to be in more severe crashes”

These implausible claims did not cause the “researchers” to question their assumptions. Such lack of scientific discipline is disturbing.

The implausible Cochrane review

In 1999, the same researchers published a “review” of helmet studies in the Cochrane review, that claims

“helmet dramatically reduces the risk of head and facial injuries for bicyclists involved in a crash, even if it involves a motor vehicle”

This claim ignores the limitations of helmets.  Polystyrene helmets are designed for minor impacts. They do not cover the face.

Brian Walker,  a helmet testing expert from helmet-testing lab Head Protection Evaluations, reports:

“Cycle helmets are designed for falls without any other vehicle involved …

The tests that cycle helmets currently go through mean that they should offer similar protection to a pedestrian who trips and falls to the ground …

In today’s road traffic accidents, it’s not unlikely for a cycle helmet to be subjected to severity loads greater than it is designed to cope with.”

The study misleading claims were rebutted by an independent researcher:

“It is concluded that the review takes no account of scientific knowledge of types and mechanisms of brain injury

This biased review attracted much criticism, including the following:

“The review is not independent. Four of the seven papers selected for inclusion were the work of the reviewers themselves 

Only case-control studies were considered for inclusion, … studies of this type are acknowledged to be prone to bias …

The paradox presented by the failure of other types of studies to show any benefit from large increases in helmet use is left unstated and unaccounted for

The authors are dismissive of the possibility of risk compensation. However, it has subsequently been demonstrated that child cyclists often ride more riskily and suffer more crashes when wearing a cycle helmet (Mok et al, 2004).

No consideration is given to rotational injuries, which dominate the most serious injuries. Helmets … may increase the risk and/or severity of rotational injury.(BHRF, 1039).

Claims are accepted of efficacy for which no plausible mechanism exists (e.g. the prevention of mid-face injuries), … and which would not be possible even if helmets prevented all head injuries (e.g. an increase of 35% in cyclists wearing helmets leading to 66% fewer head injuries).

There is misleading interpretation of ‘odds ratio’ … This exaggerates the predicted benefit of helmets and masks the fact that studies of this type are not truly predictive, being essentially the authors’ estimate … The reviewed paper showing the least benefit from helmets is omitted from computation of odds ratio, thus again exaggerating benefit.”

One of the study included reported a higher accident rate and higher neck injuries for helmeted cyclists. This was ignored in the summary.

The review claimed that cyclists would need to increase their risk-taking four-fold to overcome the protection of helmets. This claim was refuted by an independent researcher.

From research to lobbying

The helmet lobbyists used their “research” to peddle their beliefs. For example, this article entitled “Bicycle helmets: it’s time to use them” claims:

“Further delays in promoting the use of helmets will be measured in the number of lives ruined by the devastating consequences of preventable brain injury.”

This ignores that helmets can increase brain injury.


This “research” contradicts the limitations of polystyrene helmets. It ignores whole-population studies, where a large rise in helmet wearing did not show any benefit. Yet it has been influential.

Manufacturing an artificial perception has delivered profits to the helmet industry. With a piece of polystyrene selling for $100, the profits are huge. No wonder Bell sponsors racing cyclists. Let the profits roll.

 Bell advertising in the Tour de France 2011

Update July 2013

In June 2013, the US government dropped its claim that helmets reduce 85% of head injuries. It first made the claim based on the research mentioned above, but then admitted that there was no credible basis for the claim.

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