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#21
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You Still Don't Want to Wear a Helmet??
On Mar 28, 9:32*pm, (Tom Keats) wrote:
In such cases one generally doesn't bash one's head, but traditionally sticks a hand out to break one's fall (if one has enough time to actually think of doing so) and busts one's clavicle in the process. I won't address the details of the fall's mechanics; but someone reading your paragraph might think "A person generally busts his clavicle when he falls." That's completely false. When a person falls off a bike, he generally gets up, gets on the bike and continues riding. Please don't make it sound worse than it is. - Frank Krygowski |
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#22
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You Still Don't Want to Wear a Helmet??
In article ,
Frank Krygowski writes: On Mar 28, 9:32*pm, (Tom Keats) wrote: In such cases one generally doesn't bash one's head, but traditionally sticks a hand out to break one's fall (if one has enough time to actually think of doing so) and busts one's clavicle in the process. I won't address the details of the fall's mechanics; but someone reading your paragraph might think "A person generally busts his clavicle when he falls." That's completely false. When a person falls off a bike, he generally gets up, gets on the bike and continues riding. Please don't make it sound worse than it is. Of course you are quite correct, and I'd truly regret any misleadings on my part, however inadvertent. I shall nevertheless suggest that emphasis on head protection for cyclists is misplaced (or at least overdone,) and that in the list of serious injuries caused by cycling mishaps, broken clavicles rank fairly high. I should state that includes all styles of riding, including gonzo freeriding and trials. In all my years & miles of riding (and the occasional spill here 'n there) I've never suffered a broken or fractured bone. I did manage to hole a new pair of jeans a few years back, much to my chagrine. I may some day have to answer to my Maker about some of my utterings. It indeed is amazing, how bike riding actually is so safe. I understand a lot of would-be riders are held back by their unjustified fears and [mis]perceptions of danger. A nice, social Critical Mass helps to tip some of those folks over the brink and onto the good side. It's nice when people fall /into/ riding. cheers, Tom -- Nothing is safe from me. I'm really at: tkeats curlicue vcn dot bc dot ca |
#23
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You Still Don't Want to Wear a Helmet??
"landotter" wrote:
On Mar 26, 1:16 pm, DennisTheBald wrote: On Mar 20, 1:18 pm, "Dien Cai Dau" wrote: Natasha Richardson, a Tony Award-winning actress ... Was this alpine or nordic skiing? One is an extreme sport and the other rather pedestrian. Bunny slope, very low speed fall. If we were to take this as an example of where in life helmets are needed--we'd have to start with wearing them in our cars, in the shower, and while climbing stairs. You forgot walking and gardening. -- Tom Sherman - 42.435731,-83.985007 LOCAL CACTUS EATS CYCLIST - datakoll |
#24
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You Still Don't Want to Wear a Helmet??
Frank Krygowski wrote:
On Mar 28, 9:32 pm, (Tom Keats) wrote: In such cases one generally doesn't bash one's head, but traditionally sticks a hand out to break one's fall (if one has enough time to actually think of doing so) and busts one's clavicle in the process. I won't address the details of the fall's mechanics; but someone reading your paragraph might think "A person generally busts his clavicle when he falls." That's completely false. When a person falls off a bike, he generally gets up, gets on the bike and continues riding. Please don't make it sound worse than it is. A "bad" crash seems to often involve a broken thigh or clavicle in the bicycling world. The racing guys break the clavicle when they actually break something it seems. A front tire going flat put me in a situation that had I been going faster, might have broken my clavicle. Front wheel washed out on me in a turn and I went over sideways just as TK mentions. No time to put out an arm to break the fall. Landed flat on my shoulder but due to low speed, just bruised it. SMH |
#25
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You Still Don't Want to Wear a Helmet??
On Mar 27, 1:00*pm, "
wrote: On Mar 27, 12:43*pm, " wrote: On Mar 27, 5:14*am, "Bruce Gilbert" wrote: "landotter" wrote in message .... On Mar 26, 1:16 pm, DennisTheBald wrote: On Mar 20, 1:18 pm, "Dien Cai Dau" wrote: Natasha Richardson, a Tony Award-winning actress ... Was this alpine or nordic skiing? One is an extreme sport and the other rather pedestrian. Bunny slope, very low speed fall. If we were to take this as an example of where in life helmets are needed--we'd have to start with wearing them in our cars, in the shower, and while climbing stairs. I wonder if she had an aneurism ready to pop anyway, Perhaps the small impact was enough to finally burst the vessel wall. If that was the actual case, what would have happened with a doorpost, car door, or a jar falling out of the kitchen pantry? I believe this is an exraordinary case. Either that, or we really don't have all of the elements of the story. Bruce Bruce: In a simple fall, one where you simply hit the ground (or ice etc), the magnitude of the impact and possible damage from the impact does not depend on the forward velocity, it is only the velocity perpendicular to the surface that matters. *As I pointed out above, a fall from 6 feet can produce an impact velocity of about 14mph, more than enough to do serious damage. If one is doing a track stand and falls over, there is more than enough there to cause serious damage to the brain etc. The question of whether one wears a helmet in a given situation, say walking, riding a bike, skiing, sitting in a chair, *should really depend on ones ability to respond and breaking the fall and thus avoid hitting ones head. * Breaking one's fall when on skis with poles in ones hands and awkward skies on the feet makes is more difficult than when one is simply walking along. *A bicycle presents similar problems, clearing ones feet from the pedals, getting caught by the bars etc, etc. Of course this is a "simple fall." *If you hit something that stops your forward velocity, ie a tree, pole, wall, then the impact depends on your forward velocity. *But helmets are not generally designed to protect in such an event. So, one should not be surprised that serious injuries can result when the forward velocity is low, there is plenty there to do it. Jon Isaacs Dear Jon, Actually, it's almost impossible to fall straight down from a bicycle. Bicyclists usually topple to one side or the other--the frame pushes them sideways. The motion is more like the arc of a toppling tree than a severed head dropping straight down in free-fall. Surprisingly, an acorn on the top of a toppling oak tree hits the ground much faster than the same acorn dropping straight down from the top of the same tree. (That's why toppling chimneys break as they fall--the brickwork cracks because it can't stand the strain of trying to whip the top of the chimney so fast.) Joe Riel explained that the end of a rod hits the ground at the same speed as if it had been dropped in free fall from 3/2 the height of the rod: *http://groups.google.com/group/rec.b...4aad73e9e0cb44 In other words, if you topple sideways like a 6-foot tree, your head hits the ground at roughly the same speed as if it had fallen 9 feet straight down. The difference is about 20 versus 24 feet per second, so the kinetic energy is about 400x versus 576x: *http://hyperphysics.phy-astr.gsu.edu...raj.html#ffall Of course, your neck and body bend a bit as you topple sideways, like the chimney breaking, but your head still ends up hitting the ground faster than if it fell straight down. Cheers, Carl Fogel Carl: I try to keep it simple so I use the object dropped from 6 feet. In reality it is a complex situation, the tipping rod you mention is a classic problem for engineering students. The important point is that the impact in a simple fall is not a function of your forward speed but rather how far you fall and how you fall. Jon |
#26
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You Still Don't Want to Wear a Helmet??
On Mar 27, 1:07*pm, landotter wrote:
On Mar 27, 1:43*pm, " wrote: On Mar 27, 5:14*am, "Bruce Gilbert" wrote: "landotter" wrote in message .... On Mar 26, 1:16 pm, DennisTheBald wrote: On Mar 20, 1:18 pm, "Dien Cai Dau" wrote: Natasha Richardson, a Tony Award-winning actress ... Was this alpine or nordic skiing? One is an extreme sport and the other rather pedestrian. Bunny slope, very low speed fall. If we were to take this as an example of where in life helmets are needed--we'd have to start with wearing them in our cars, in the shower, and while climbing stairs. I wonder if she had an aneurism ready to pop anyway, Perhaps the small impact was enough to finally burst the vessel wall. If that was the actual case, what would have happened with a doorpost, car door, or a jar falling out of the kitchen pantry? I believe this is an exraordinary case. Either that, or we really don't have all of the elements of the story. Bruce Bruce: In a simple fall, one where you simply hit the ground (or ice etc), the magnitude of the impact and possible damage from the impact does not depend on the forward velocity, it is only the velocity perpendicular to the surface that matters. *As I pointed out above, a fall from 6 feet can produce an impact velocity of about 14mph, more than enough to do serious damage. If one is doing a track stand and falls over, there is more than enough there to cause serious damage to the brain etc. The question of whether one wears a helmet in a given situation, say walking, riding a bike, skiing, sitting in a chair, *should really depend on ones ability to respond and breaking the fall and thus avoid hitting ones head. * And your methodology used for measuring this ability is?? Skiing on bunny slopes and sober solo road cycling are statistically safe. Statistics are what matters--not your bizarre reasoning where really brave sky divers might eschew a chute altogether because, "dood, I can break the fall." Hi: I am not a statistic nor are you. Cycling is statistically safe but there are things one can do to better one's chances, some of these things are quite important, lights at night, a well prepared bicycle, riding according to the rules of the road. Some are less important but still significant. Wearing a helmet is one of these. Jon |
#27
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You Still Don't Want to Wear a Helmet??
On Mar 27, 6:37*pm, Frank Krygowski wrote:
On Mar 27, 2:43*pm, " wrote: On Mar 27, 5:14*am, "Bruce Gilbert" wrote: "landotter" wrote in message .... On Mar 26, 1:16 pm, DennisTheBald wrote: On Mar 20, 1:18 pm, "Dien Cai Dau" wrote: Natasha Richardson, a Tony Award-winning actress ... Was this alpine or nordic skiing? One is an extreme sport and the other rather pedestrian. Bunny slope, very low speed fall. If we were to take this as an example of where in life helmets are needed--we'd have to start with wearing them in our cars, in the shower, and while climbing stairs. I wonder if she had an aneurism ready to pop anyway, Perhaps the small impact was enough to finally burst the vessel wall. If that was the actual case, what would have happened with a doorpost, car door, or a jar falling out of the kitchen pantry? I believe this is an exraordinary case. Either that, or we really don't have all of the elements of the story. Bruce Bruce: In a simple fall, one where you simply hit the ground (or ice etc), the magnitude of the impact and possible damage from the impact does not depend on the forward velocity, it is only the velocity perpendicular to the surface that matters. ... Of course this is a "simple fall." *If you hit something that stops your forward velocity, ie a tree, pole, wall, then the impact depends on your forward velocity. *But helmets are not generally designed to protect in such an event. The other event that helmets are not designed to protect is an angular acceleration of the skull and brain, and in that situation, the forward velocity may matter. Angular brain acceleration is thought by many to be more damaging than linear acceleration. *Boxers know this, and use it when trying to cause brain damage (e.g. a knockout) in their opponent. *But bike helmets are not designed to mitigate angular acceleration. And in fact, they may make it worse. *It's likely that the characteristics of the human scalp - with its slippery hair and low- friction attachment to the skull - evolved to reduce such angular acceleration. *Not only do helmets lack those features, but they increase the moment arm of any tangential force. *This may be part of the reason widespread use of helmets has not resulted in improvements over bicycling's already low rate (per cyclist) of serious head injuries. So, one should not be surprised that serious injuries can result when the forward velocity is low, there is plenty there to do it. No matter what your activity. I was hiking Sunday along a creekside trail at a place famous for its countless large rocks. *At one spot, I tripped over one rock in a rock field and fell forward very suddenly. *Luckily I caught myself with my hands; but if my hands had not broken my fall, my head hitting a boulder could have caused a serious head injury. But despite the many warning signs regarding kayaking with care, avoiding swimming, monitoring children, etc, there were none recommending hikers wear helmets. *Go figure. - Frank Krygowski The angular accelerations in a fall are much smaller than the linear accelerations caused by the impact with the pavement. Your description of your fall when hiking nicely illustrates my previous point: When walking one has their hands free and is able to break the fall just as you did. Had you been on a bicycle, it could have been significantly more difficult to catch yourself and you just might have hit your head. Man has clearly evolved to optimize walking as the primary form of personal transport, catching oneself when stumbling or falling is critical to the continuation of the species. Similar responses can help one in the case of a fall from a bicycle or other mechanical device but it is not so straightforward and natural. Things can happen much more quickly on a bicycle than when walking which means a rider just may not have time to respond. Jon Isaacs |
#28
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You Still Don't Want to Wear a Helmet??
On Mar 29, 10:11*am, (Tom Keats) wrote:
In article , * * * * Frank Krygowski writes: On Mar 28, 9:32*pm, (Tom Keats) wrote: In such cases one generally doesn't bash one's head, but traditionally sticks a hand out to break one's fall (if one has enough time to actually think of doing so) and busts one's clavicle in the process. I won't address the details of the fall's mechanics; but someone reading your paragraph might think "A person generally busts his clavicle when he falls." *That's completely false. When a person falls off a bike, he generally gets up, gets on the bike and continues riding. *Please don't make it sound worse than it is. Of course you are quite correct, and I'd truly regret any misleadings on my part, however inadvertent. I shall nevertheless suggest that emphasis on head protection for cyclists is misplaced (or at least overdone,) and that in the list of serious injuries caused by cycling mishaps, broken clavicles rank fairly high. *I should state that includes all styles of riding, including gonzo freeriding and trials. In all my years & miles of riding (and the occasional spill here 'n there) I've never suffered a broken or fractured bone. I did manage to hole a new pair of jeans a few years back, much to my chagrine. I may some day have to answer to my Maker about some of my utterings. It indeed is amazing, how bike riding actually is so safe. *I understand a lot of would-be riders are held back by their unjustified fears and [mis]perceptions of danger. *A nice, social Critical Mass helps to tip some of those folks over the brink and onto the good side. *It's nice when people fall /into/ riding. cheers, * * * * Tom -- Nothing is safe from me. I'm really at: tkeats curlicue vcn dot bc dot ca A few simple thoughts: - Clavicles, hands, legs, sprains, all that stuff, it heals... Brain damage is a different issue... - In my world, Helmets are not the SOLUTION to safe cycling and their use is probably over emphasized as a cure all, Wear a helmet is easy to say... Teaching someone to ride properly is not. On the other hand, over emphasized or not, that does not diminish the value too me of wearing a helmet. - It is not really amazing that cycling is so safe, in general one is traveling at relatively low speeds, other vehicle operators pretty much look out for cyclists and expect erratic behavior. The guy weaving across the busy intersection at night against the light without any lights or reflectors will make it better than 999 times out of 1000, he is looking, the cars are looking, they have seen it many times before... And in situations like that, a helmet is not going to make much difference... Jon Isaacs |
#29
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You Still Don't Want to Wear a Helmet??
On Mar 20, 10:18*am, "Dien Cai Dau" wrote:
Natasha Richardson, a Tony Award-winning actress whose career melded glamorous celebrity with the bloodline of theater royalty, died Wednesday at Lenox Hill Hospital in Manhattan. She had suffered head injuries in a skiing accident Monday north of Montreal, and was flown to New York on Tuesday. She was 45 and lived in Manhattan and in Millbrook, N.Y. Ms. Richardson, who was not wearing a helmet, had fallen during a beginner's skiing lesson, a resort spokeswoman, Lyne Lortie, said Tuesday. "It was a normal fall; she didn't hit anyone or anything," Ms. Lortie said. "She didn't show any signs of injury. She was talking and she seemed all right." Can you tell me how many significant head injuries per million person- hours (or person-days) of downhill snow sports? That would give us an idea of whether it's a significant risk or not, and we could compare to other 'dangerous' activities like walking or taking a bath. |
#30
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You Still Don't Want to Wear a Helmet??
Dien Cai Dau wrote:
Natasha Richardson, a Tony Award-winning actress whose career melded glamorous celebrity with the bloodline of theater royalty, died Wednesday at Lenox Hill Hospital in Manhattan. She had suffered head injuries in a skiing accident Monday north of Montreal, and was flown to New York on Tuesday. She was 45 and lived in Manhattan and in Millbrook, N.Y. Ms. Richardson, who was not wearing a helmet, had fallen during a beginner's skiing lesson, a resort spokeswoman, Lyne Lortie, said Tuesday. "It was a normal fall; she didn't hit anyone or anything," Ms. Lortie said. "She didn't show any signs of injury. She was talking and she seemed all right." Mostly what I want is the right to make the decision for myself. What I do not want is nosey nate making decisions for me. |
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