Sledding athletes are taking their lives • Hacker News Board

Re: Sledding athletes are taking their lives

#41

Post by etrautmann » Mon, Jul 27, 2020, 4:04 AM UTC

nimih wrote: post #26

pengaru wrote: post #15

Earlier quoted context omitted.

Except measuring G-forces acting on a helmet doesn't directly relate to the forces acting on the head within it.

Why not? To me (a layperson in the physics of helmets and brains), they would seem to be quite directly related, especially when the cause of the gees is not related to an impact.

The helmet is a light mass, which can move relative to the head, and experience drastically higher g-forces for very short times. Sampling an accelerometer at kHz rates as a helmet is vibrating (without translating all of the vibrational energy into the head), will measure larger peak G's than the head experiences.

For this reason, when studying head impact for football players, they mount the accelerometers in the mouth guard. This more accurately reflects the real g-forces, as the teeth (ideally) don't move much relative to the brain during an impact, and have the appropriate reference frame.

The differences can be extremely large. The peaks reflected in this graph are absolutely not real and should not be taken literally.

Re: Sledding athletes are taking their lives

#42

Post by WalterBright » Mon, Jul 27, 2020, 4:04 AM UTC

elgenie wrote: post #12

WalterBright wrote: post #4

How terribly sad. Perhaps the speeds of the sled tracks could be reduced. A helmet designed to blunt the millisecond g force spikes could also be developed.

The issue with helmet design is likely the same one football players face: that the place the impact absorbing material needs to go is between skull and brain. There’s no wearable helmet that’s going to change the result of skull being decelerated or accelerated as the brain keeps going. A strap or some padding that absorbs fleeting contact with the ice maybe has a chance to make a difference, but there are so few pe…

The integral of the force of time would be the same, but one can reduce the spikes in force.

That's essentially what happens when a car is designed to crush, saving the occupants. The deceleration of the occupants is reduced and spread out over a longer period of time, but the total deceleration is the same.

Re: Sledding athletes are taking their lives

#43

Post by WalterBright » Mon, Jul 27, 2020, 4:05 AM UTC

elliottkember wrote: post #24

Swizec wrote: post #23

Earlier quoted context omitted.

Wouldn’t the fact that your skull decelerates slower against an airbag than against a steering wheel mean that your brain hits your skull with less force?

Yes, that's what it does. It's not zero, but it's definitely less. But you probably only hit an airbag a couple of times max over the course of your lifetime, whereas on the field you'll hit your head the whole game. And I don't know how you could put an airbag in a helmet, there's not enough space to slow your impact

Make the helmet bigger, and put a liner filled with gel in it.

Re: Sledding athletes are taking their lives

#44

Post by Noumenon72 » Mon, Jul 27, 2020, 4:06 AM UTC

This is how the world is shaping up -- winner take all, but so much competition to be that winner that the winner's life isn't worth it either.

Re: Sledding athletes are taking their lives

#45

Post by amluto » Mon, Jul 27, 2020, 4:06 AM UTC

pengaru wrote: post #38

vaidhy wrote: post #37

Earlier quoted context omitted.

You are confusing the ability to sustain the g-force by the brain with the force experienced. A padding on the helmet helps in event of collision, not the g-force which is due to the acceleration

How is a collision not just another acceleration?

In a collision, the helmet gets hit and, subject to some degree of padding and such, transfers the impact to the head. If you’re sitting in a sled and the sled accelerated rapidly, your head and your helmet must accelerate with it, although you may not perfectly track its path. Unless the helmet is also secured to your torso, all the forces on the helmet come from your head. You would need tremendous acceleration of your head to meaningfully deform any but the softest padding.

Re: Sledding athletes are taking their lives

#46

Post by SenHeng » Mon, Jul 27, 2020, 4:08 AM UTC

matz1 wrote: post #22

gnramires wrote: post #19

This seems totally unacceptable. We should stop having this sport in the Olympics (implicitly supporting this madness) -- of course athletes are free to do as they chose, but we cannot encourage such pointless self-destruction and misery. An alternative to save the sport is completely redesign it to limit maximum accelerations. Usually injuries follow power laws so I doubt even that much reduction would be necessary…

>pointless self-destruction and misery. Maybe its pointless for you, fair enough but it can be meaningfull for other people, i myself think it's interesting.

matz should not be downvoted. Humans do lots of objectively pointless self-destruction like things as a hobby with increasing risks. Things like human powered flight, aerogliding and sky diving, parkour, climbing steep things with and without gear, driving at high speeds around bends, 'explore' the wild, many of which we celebrate, reward and encourage.

Re: Sledding athletes are taking their lives

#47

Post by SamWhited » Mon, Jul 27, 2020, 4:09 AM UTC

pengaru wrote: post #15

JumpCrisscross wrote: post #13

> On Feb. 22, 2013, Morris attached an accelerometer to his helmet, then launched his body down a 1,500-meter track at the sliding center in Whistler, British Columbia, which is considered the fastest track in the world and was a venue for the 2010 Winter Olympics. Bobsleigh has been a feature of the Winter Olympics since 1924 [1]. Yet it might have taken until 2013 for someone to measure its g force on its athletes'…

Except measuring G-forces acting on a helmet doesn't directly relate to the forces acting on the head within it.

It doesn't matter. You don't have to measure something perfectly and exactly to decide if it's an avenue of research worth exploring. If turns are designed to limit G-forces to 5G, and you put sensors on your helmet and they're reading 55G when your head hits the ice, that's probably an indication that further research is required.

Re: Sledding athletes are taking their lives

#48

Post by SenHeng » Mon, Jul 27, 2020, 4:17 AM UTC

Jeremy Clarkson did a pretty good piece on how scary bobsleighs are 10 years ago on Top Gear. Worth taking a peak to see what all the fuss is about.

https://youtu.be/xsac2agog48

And for those interested in what a skeleton looks and feels like. Here's a more recent video.

https://youtu.be/BzxS-3vO6Gw

Re: Sledding athletes are taking their lives

#49

Post by Oreb » Mon, Jul 27, 2020, 4:22 AM UTC

asciident wrote: post #3

From my naive understanding based on reading the article, I don't see how sledding is any more of a sport than a video game combined with fear tolerence.

Elite sledders are phenomenal athletes, often from a background of sprinting or Olympic weightlifting. Accelerating the sled takes tremendous power and strength.

Re: Sledding athletes are taking their lives

#50

Post by Markoff » Mon, Jul 27, 2020, 4:24 AM UTC

that's lot of assumptions why they are taking their lives, but I'm missing comparison with suicide rate in other sports

3 athletes in 7 years in one sport doesn't seem out of ordinary in extremely stressful environment where each millisecond counts