helmets increase danger
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From: Albert T Cone on 7 Apr 2010 10:24 Derek C wrote: > On 6 Apr, 17:13, Albert T Cone <a.k.ki...(a)durham.ac.uk> wrote: >> JMS wrote: >>> On Thu, 01 Apr 2010 09:21:48 +0100, Albert T Cone >>> <a.k.ki...(a)durham.ac.uk> wrote: >>>> JMS wrote: >>>>> The fact that Walker is a rabid anti-helmet psycholist was sufficient >>>>> reason for mis-representing that data. >>>> There are very good arguments for not wearing a helmet - the pro/con >>>> debate is not at all clear cut. >>> Are you against them by any chance? >> No. I don't wear one myself, if you are interested, because I prefer >> the risk of abrasions and blunt trauma injury to those of torsional >> injury to the neck and spine. Other people may weigh those risks >> differently, but I think that it *should* be a personal choice, and I am >> not in favour of making helmet wearing mandatory. > > Only 2% of cyclists hospitalised after accidents suffered a neck > injury, but 38% suffered head injuries in 2008. I would estimate that > about 50% of cyclists wear cycle helmets, so not a very convincing > argument. But what fraction of those head injuries were severe, or indeed the cause of hospitalisation? What fraction of the DAI (spinal/neck) injuries were severe and/or the cause of hospitalisation? What speed were the cyclists travelling at (i.e. do they ride like I ride?) There have been a significant number of case studies and time trial analyses, but the statistics remain unclear. Cycle helmets increase the risk of concussion, but reduce the average severity of concussions, reduce the risk of abrasions, reduce the risk of penetrating injuries [1] and increase the risk of torsional DAI injuries. I am unconcerned about concussions or abrasions, since they are very unlikely to have a long-term effect on my life. I am concerned about penetrating injuries and DAIs, so when I am doing something with a high risk of sharp pointy things hitting my head, such as downhilling, then I wear a full-face helmet, but the rest of the time I don't wear a helmet, since that seems to be the best compromise *for me*. [1] The KE involved in an impact scales as (impact speed)^2. A first-order model is that Helmets offer a fixed percentage reduction in severity up to a failure KE. Due to the square-law scaling, the range of speeds over which the KE ranges from "insufficient to do serious damage without helmet" to "Helmet doesn't protect you anyway" is quite narrow. My best *estimate* is that up to 20 mph you aren't going to kill yourself without one, and above 25mph, it isn't going to help you anyway.
From: Derek C on 7 Apr 2010 11:51 On 7 Apr, 15:24, Albert T Cone <a.k.ki...(a)durham.ac.uk> wrote: > Derek C wrote: > > On 6 Apr, 17:13, Albert T Cone <a.k.ki...(a)durham.ac.uk> wrote: > >> JMS wrote: > >>> On Thu, 01 Apr 2010 09:21:48 +0100, Albert T Cone > >>> <a.k.ki...(a)durham.ac.uk> wrote: > >>>> JMS wrote: > >>>>> The fact that Walker is a rabid anti-helmet psycholist was sufficient > >>>>> reason for mis-representing that data. > >>>> There are very good arguments for not wearing a helmet - the pro/con > >>>> debate is not at all clear cut. > >>> Are you against them by any chance? > >> No. I don't wear one myself, if you are interested, because I prefer > >> the risk of abrasions and blunt trauma injury to those of torsional > >> injury to the neck and spine. Other people may weigh those risks > >> differently, but I think that it *should* be a personal choice, and I am > >> not in favour of making helmet wearing mandatory. > > > Only 2% of cyclists hospitalised after accidents suffered a neck > > injury, but 38% suffered head injuries in 2008. I would estimate that > > about 50% of cyclists wear cycle helmets, so not a very convincing > > argument. > > But what fraction of those head injuries were severe, or indeed the > cause of hospitalisation? What fraction of the DAI (spinal/neck) > injuries were severe and/or the cause of hospitalisation? What speed > were the cyclists travelling at (i.e. do they ride like I ride?) > > There have been a significant number of case studies and time trial > analyses, but the statistics remain unclear. > > Cycle helmets increase the risk of concussion, but reduce the average > severity of concussions, reduce the risk of abrasions, reduce the risk > of penetrating injuries [1] and increase the risk of torsional DAI injuries. > > I am unconcerned about concussions or abrasions, since they are very > unlikely to have a long-term effect on my life. I am concerned about > penetrating injuries and DAIs, so when I am doing something with a high > risk of sharp pointy things hitting my head, such as downhilling, then I > wear a full-face helmet, but the rest of the time I don't wear a helmet, > since that seems to be the best compromise *for me*. > > [1] The KE involved in an impact scales as (impact speed)^2. A > first-order model is that Helmets offer a fixed percentage reduction in > severity up to a failure KE. Due to the square-law scaling, the range > of speeds over which the KE ranges from "insufficient to do serious > damage without helmet" to "Helmet doesn't protect you anyway" is quite > narrow. My best *estimate* is that up to 20 mph you aren't going to > kill yourself without one, and above 25mph, it isn't going to help you > anyway.- Hide quoted text - > > - Show quoted text - The problem is that just gently toppling off your bike at low speed and striking your head on a paving stone or the road can cause a possibly fatal skull fracture. As a child I managed to fracture my upper jawbone and damage my teeth when I skidded off my bike rounding a corner at quite low speed and struck a kerbstone with my bare head. I was also mildly concussed. That was before cycle helmets were available BTW. Although bicycle helmets are less strong than motorcycle helmets, they seem to give some protection in even quite high speed accidents according to some research. They help to spread the load of point impacts and reduce the g loading on the brain by a factor of about 4. Please read TRL Report PPR 446 for more information on this. There is also plenty of good stuff in cyclehelmets.org, but please ignore the totally biased commentary, as this site seem to be dedicated to trying to prove that cycle helmets don't work. Derek C
From: JMS jmsmith2010 on 7 Apr 2010 12:21 On Tue, 6 Apr 2010 10:18:03 -0700 (PDT), Derek C <del.copeland(a)tiscali.co.uk> wrote: >On 6 Apr, 17:13, Albert T Cone <a.k.ki...(a)durham.ac.uk> wrote: >> JMS wrote: >> > On Thu, 01 Apr 2010 09:21:48 +0100, Albert T Cone >> > <a.k.ki...(a)durham.ac.uk> wrote: >> >> >> JMS wrote: >> >>> The fact that Walker is a rabid anti-helmet psycholist was sufficient >> >>> reason for mis-representing that data. >> >> There are very good arguments for not wearing a helmet - the pro/con >> >> debate is not at all clear cut. >> >> > Are you against �them by any chance? >> >> No. �I don't wear one myself, if you are interested, because I prefer >> the risk of abrasions and blunt trauma injury to those of torsional >> injury to the neck and spine. �Other people may weigh those risks >> differently, but I think that it *should* be a personal choice, and I am >> not in favour of making helmet wearing mandatory. > >Only 2% of cyclists hospitalised after accidents suffered a neck >injury, but 38% suffered head injuries in 2008. I would estimate that >about 50% of cyclists wear cycle helmets, so not a very convincing >argument. > >The most common injuries to cyclists are to the hands, arms and >shoulders, so perhaps protection should be worn in those areas? > >Derek C I think they are less likely to die from injuries to those parts of their bodies, than they are from those to the head - don't you? -- "wearing helmets can sometimes increase the chance of a cyclist being involved in an accident." That august body The CTC (They've already had a slap for lying by the ASA)
From: Derek C on 7 Apr 2010 12:36 On 7 Apr, 17:21, JMS <jmsmith2...(a)live.co.uk > wrote: > On Tue, 6 Apr 2010 10:18:03 -0700 (PDT), Derek C > > > > > > <del.copel...(a)tiscali.co.uk> wrote: > >On 6 Apr, 17:13, Albert T Cone <a.k.ki...(a)durham.ac.uk> wrote: > >> JMS wrote: > >> > On Thu, 01 Apr 2010 09:21:48 +0100, Albert T Cone > >> > <a.k.ki...(a)durham.ac.uk> wrote: > > >> >> JMS wrote: > >> >>> The fact that Walker is a rabid anti-helmet psycholist was sufficient > >> >>> reason for mis-representing that data. > >> >> There are very good arguments for not wearing a helmet - the pro/con > >> >> debate is not at all clear cut. > > >> > Are you against them by any chance? > > >> No. I don't wear one myself, if you are interested, because I prefer > >> the risk of abrasions and blunt trauma injury to those of torsional > >> injury to the neck and spine. Other people may weigh those risks > >> differently, but I think that it *should* be a personal choice, and I am > >> not in favour of making helmet wearing mandatory. > > >Only 2% of cyclists hospitalised after accidents suffered a neck > >injury, but 38% suffered head injuries in 2008. I would estimate that > >about 50% of cyclists wear cycle helmets, so not a very convincing > >argument. > > >The most common injuries to cyclists are to the hands, arms and > >shoulders, so perhaps protection should be worn in those areas? > > >Derek C > > I think they are less likely to die from injuries to those parts of > their bodies, than they are from those to the head - don't you? > -- Falling off a bicycle usually hurts. I know because I have done so on several occasions. Bikes have no crumple zone, seat belts or airbags to protect you in the event of an accident. Large grazes and broken bones are the most likely injuries. Even the former can be life threatening if they become infected. However brain injuries are the most likely to cause your premature demise. Derek C
From: nmm1 on 7 Apr 2010 13:04
In article <1b11cb23-e7a6-4ace-bc82-fe6f57f9dc72(a)x3g2000yqd.googlegroups.com>, Derek C <del.copeland(a)tiscali.co.uk> wrote: > >The problem is that just gently toppling off your bike at low speed >and striking your head on a paving stone or the road can cause a >possibly fatal skull fracture. As a child I managed to fracture my >upper jawbone and damage my teeth when I skidded off my bike rounding >a corner at quite low speed and struck a kerbstone with my bare head. >I was also mildly concussed. That was before cycle helmets were >available BTW. No, that is one problem. Another is that bicycle helmets make it more likely that you will strike your head, and increase the impact when you do. That excludes various other effects, such as whether they are more likely to make the rider careless, or to encourage motorists to endanger the cyclist. The result is that we simply do not know whether wearing a bicycle helmet is likely to increase or reduce the risk of brain damage. Either is possible, but the statistics indicate that their effect is very small, whichever way it is. Regards, Nick Maclaren. |