Does your riding position influence the chances of head injury?

[bjlabuk]

As for riding outside of his ability... ah, it appears he has actually admitted it, himself. If you travel at a speed where you can't detect a hazard then you are travelling outside your ability..... the moral being 'don't ride at a speed where you can not spot a hazard on the road.. whether that's a pothole, tree trunk, parked vehicle, dead badger or whatever'...(I think its even mentioned in the highway code)... and the second moral being 'there ain't never been a road which can't or doesn't form a pothole.. the moment you stop looking for 'em, is the moment you'll find one'. The second moral came from a highways engineer...

Well Rule 126 states "Stopping distances. Drive at a speed that will allow you to stop well within the distance you can see to be clear ahead." So you are right. The same principle should apply when you are riding a bike.

[cycle tramp]

So way back in December of last year, I publicly ruminated that idea that not only how you ride your bike, but your actual riding position should influence whether you should wear a helmet..

My thanks go to Mattheus for this clip https://m.youtube.com/watch?v=VxWpwWByP ... gAo7VqN5tD which shows people riding bikes, whose handlebars are higher than their saddles, falling off their bikes and not hitting their heads... to all those who demand that cyclists should where helmets, based on the above clip, I now counter that demand with my own.. in that no cycle should have their handlebars lower than 1 inch above saddle height!
Indeed the last rider, perhaps thanks to an open frame without a cross bar, manages to gracefully fall on their bum...
..no doubt the industry will bring out a plastic and foam bum helmet in the future..

[Mike Sales]

"What goes up must come down" is a cheering thought when climbing a pass. After reaching the top I always felt more stable with a lower centre of gravity on the drops when claiming my just reward.
When flogging into a head wind getting the back a bit flatter eases the effort.
I would not venture to force others to follow my prescription.

[mattheus]

So way back in December of last year, I publicly ruminated that idea that not only how you ride your bike, but your actual riding position should influence whether you should wear a helmet..

My thanks go to Mattheus for this clip https://m.youtube.com/watch?v=VxWpwWByP ... gAo7VqN5tD which shows people riding bikes, whose handlebars are higher than their saddles, falling off their bikes and not hitting their heads... to all those who demand that cyclists should where helmets, based on the above clip, I now counter that demand with my own.. in that no cycle should have their handlebars lower than 1 inch above saddle height!
...

I think you've drawn the wrong conclusion from this data: they are safe because they're riding on the right. Or possibly because it's winter. Or maybe they all have black tyres? So many possiblities ...

[pjclinch]

"What goes up must come down" is a cheering thought when climbing a pass. After reaching the top I always felt more stable with a lower centre of gravity on the drops when claiming my just reward.
When flogging into a head wind getting the back a bit flatter eases the effort.
I would not venture to force others to follow my prescription.

This is what 'bents do best...
Not only faster into the wind but you get a default view of where you're going.

Pete.

[cycle tramp]

So way back in December of last year, I publicly ruminated that idea that not only how you ride your bike, but your actual riding position should influence whether you should wear a helmet..

My thanks go to Mattheus for this clip https://m.youtube.com/watch?v=VxWpwWByP ... gAo7VqN5tD which shows people riding bikes, whose handlebars are higher than their saddles, falling off their bikes and not hitting their heads... to all those who demand that cyclists should where helmets, based on the above clip, I now counter that demand with my own.. in that no cycle should have their handlebars lower than 1 inch above saddle height!
...

I think you've drawn the wrong conclusion from this data: they are safe because they're riding on the right. Or possibly because it's winter. Or maybe they all have black tyres? So many possiblities ...

I don't believe so... if you look at how they fall, each one has time to put their arm out to slow their fall and prevent their head from contacting the tarmac... if their hands had been at saddle height or less, there would have been less time to do this...

[Nearholmer]

The fall they take is pretty much exactly the one I took on ice in very similar circumstances, while riding my old Pashley shopping bike, so even a half-similar bike, and guess what? I hit my head, the only time I’ve definitely done so coming off a bike, although I’m fairly sure I also did as a teenager coming off a “racer” on a plain straight road in dry weather.

I went down as they do, sort of sideways to the right and almost backwards, as the bike disappeared out from under me forwards and to the left. My right arm and shoulder hit the deck, then an instant later the right side of my head.

Basically, as with this entire thread, I think there is far too much guesswork going into the interpretation of a tiny amount of solid information (in this case what we can see in the video).

There are so many factors involved in falls, and so many possible “fall modes”, that I still hold that the one certainty is that cycling speed is a really important factor when it comes to collisions between the head and fixed objects (including the ground). This is simply because the slower you are going, the more time you are likely to have to react to protect yourself, and because speed has a dominant affect on the kinetic energy involved, and that all other things being equal the more kinetic energy that gets dissipated in your head then the worse the outcome is likely to be. If there is a correlation between coming away from a fall relatively unscathed and having been riding a “Dutch” bike (and we don’t actually know whether there is or isn't, that is just a guess), it is possibly because there is a correlation between riding “Dutch” bikes and riding slowly - they are a devil of a job to get going fast!

[deeferdonk]

i've come off a drop bar/racing configuration bike on black ice and not hit my head also. No one video'd it though.

My mine take from the video was that the cyclists who came off didn't appear to attempt to warn the next cyclists of the hazard.

[Cugel]

Basically, as with this entire thread, I think there is far too much guesswork going into the interpretation of a tiny amount of solid information (in this case what we can see in the video).

There are so many factors involved in falls, and so many possible “fall modes”, that I still hold that the one certainty is that cycling speed is a really important factor when it comes to collisions between the head and fixed objects (including the ground). This is simply because the slower you are going, the more time you are likely to have to react to protect yourself, and because speed has a dominant affect on the kinetic energy involved, and that all other things being equal the more kinetic energy that gets dissipated in your head then the worse the outcome is likely to be.

Guesswork - yes.

Speed kills - a commonplace observation in many domains, from car crashes to getting killed by a lump of wood flying back into the operator of a tabesaw without a riving knife.

**********
Even in slow speed falls and similar, few humans have the speed-of-thought or physical reaction to "manage" that fall. I can only recall a very few times of all those at which I've fallen down when the event was so slow that I could think, "I'll do this to reduce the harm" then did it.

And some falls, even if slow, offer no opportunity to actually do anything. When falling backwards, for instance, you can't put your arms out to save the back of your head contacting the ground. I know this from ice skating, fell walking and even gardening events in which the forward slide of the feet is rather faster than the forward movement of the rest of one's personage.

**********
Guesswork - yes.

Most when-cycling falls are too rapid to allow the human involved to think and do things in mitigation. Maybe just a slow topple whilst attempting and failing a track-stand? Cycling falls can also occur in all sorts of fashions. Most of them seem to to involve a body-whack absorbing most of the force before any head-whack, the main exception being a face-plant - which damages the face rather than the upper skull.

Perhaps some clever boffin could arrange crash dummy testing of a vast variety in cycling mode to reveal the rate and degree of head bangs for different kinds of fall? But test dummies don't have innate and instinctive reactions like live cyclists do.

The only time I've ever been knocked off a bike (1/6/80) I badly broke my wrist by instinctively putting my hands out as I fell. It was the only injury I had - no head bang and not even any gravel rash. If only I'd though, "I'll do a forward roll on one shoulder as I unship my feet from the clips & straps then spring to my feet after two forward rolls". Alas, there seemed no time between the car-knock and the tarmac snapping my wrist to think anything at all.

[pjclinch]

There are so many factors involved in falls, and so many possible “fall modes”, that I still hold that the one certainty is that cycling speed is a really important factor when it comes to collisions between the head and fixed objects (including the ground). This is simply because the slower you are going, the more time you are likely to have to react to protect yourself, and because speed has a dominant affect on the kinetic energy involved, and that all other things being equal the more kinetic energy that gets dissipated in your head then the worse the outcome is likely to be. If there is a correlation between coming away from a fall relatively unscathed and having been riding a “Dutch” bike (and we don’t actually know whether there is or isn't, that is just a guess), it is possibly because there is a correlation between riding “Dutch” bikes and riding slowly - they are a devil of a job to get going fast!

The crucial part of speed which will break bones isn't the speed you're travelling at when you hit something but how much of that speed you lose and how quickly. The ground tends to stop one falling downwards quite quickly, and the harder it is the faster you stop, but if you're travelling fast horizontally it needs something like a wall to decelerate you as fast.
Look at Moto GP slide-outs for an excellent demonstration of this: these guys are going properly fast, but because they can slide for tens of meters they dissipate their kinetic energy relatively slowly. If they'd hit walls at those speeds it would be horror-show stuff.

The amount of time you have before you hit the ground after a fall is purely down to your height above the ground, because any vertical speed you have will be due to gravity rather than the horizontal speed of travel. A typical average adult fall from cycling height will give your head an impact speed in the vertical plane of ~ 12 mph (also about the same speed you'd have from just tripping over), and that's why helmets are specced for ~ 12 mph crashes. Fall time will be the same whether you cover no distance horizontally or whether you travel quite some distance: might not seem that way in the air but that's the physics (though it will be longer if you were going downhill as the horizontal travel takes the ground away from you as you fall).

Lateral speed will quite possibly involve skin loss, and if you come up against a wall, kerb etc. the faster you're going the worse the news is, but overall KE is not the determinant it's often assumed to be, as the motorcyclists sliding off in Moto GP show.

(I think you're completely right about the level of conjecture going on, btw, videos like the one mattheus posted are simply rejoinders to the assumption that helmets are "essential" and hitting one's head in a fall is practically certain, not any sort of "proof" that an opafiets or its riding position are proof against head injury.)

Pete.

[drossall]

My mine take from the video was that the cyclists who came off didn't appear to attempt to warn the next cyclists of the hazard.

I thought that too.

[Nearholmer]

Pete,

You are right about rate of dissipation of the kinetic energy, and there must be two limiting conditions: the rider hitting a hugely heavy, non-yielding object full on, the moment they depart from the bike (“straight into a brick wall or giant spike”) where nearly all of it (everything left after bending the bike!) is dissipated in the rider near instantaneously; and, landing on a planar surface that offers zero friction, where it dissipates really, really slowly in air resistance.

I would suggest that most events lie between the two extremes, where the impact is with things like cheese-grater road surfaces, kerbs, soft vegetation, unyielding vegetation, parked cars, another cyclist …… the list is endless, but for any given circumstance the faster you are going, the worse it will be.

[Nearholmer]

Most when-cycling falls are too rapid to allow the human involved to think and do things in mitigation

Agree; there isn't usually time to think. In the ice incident i mentioned above i was on the deck before I had even realised I was falling.

But, what has impressed me when falling over, and falling off a bike, is how much instinctual action one takes, really quickly, without thinking.

Flinging your hands out when falling forward is an obvious instinct, but another one that I’ve noticed, and which indirectly cost me two front teeth, is jaw-clenching/bracing. I twice came off where I very definitely instinctively clamped my jaw, on neither occasion hitting my head or face, but it caused vertical hairline splits in two front teeth.

We must have some pretty well evolved software to detect sudden accelerations and prepare for impacts.

[pjclinch]

Even in slow speed falls and similar, few humans have the speed-of-thought or physical reaction to "manage" that fall. I can only recall a very few times of all those at which I've fallen down when the event was so slow that I could think, "I'll do this to reduce the harm" then did it.

I recall an interview with Katie Archibald where she'd broken something and she said that in her line of work they were trained to roll when it all went worng (no broken collar bone that way), but theory somewhat easier than practice.

Looking at the chap that ended up in a ravine recently at the Giro and didn't break anything at all, I suspect most of it is down to how the Fates are looking down on you that day.

Pete.

[pjclinch]

I would suggest that most events lie between the two extremes, where the impact is with things like cheese-grater road surfaces, kerbs, soft vegetation, unyielding vegetation, parked cars, another cyclist …… the list is endless, but for any given circumstance the faster you are going, the worse it will be.

Though I often here ex pro cyclists in commentary looking on at stoopid peloton salads pointing out that sometimes the low speed crashes seem to be worse. Perhaps (conjecture klaxon!) hitting the deck more horizontally lowers the chance of the classic broken collar bone from an outstretched arm?

Beyond that, stuff like abrasives are unpleasant but don't actually break bones, so speed is bad, but that's icing on the cake of crashing being bad.

Pete.