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Sledding athletes are taking their lives

nytimes.com

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Re: Sledding athletes are taking their lives

#191

Post by low_common »

briefcomment wrote: post #184
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…

I feel like we should demonetize competitive sports. Sports are wonderful, but money (and maybe fame) incentivizes you past the point where you stop based on how your body feels. Maybe we miss out on records and storylines, but I think there are much healthier ways of spending our time.

None of these guys were getting paid to be bobsledders. I suppose they get endorsements and such, but they didn't become millionaires based on a salary alone.

Re: Sledding athletes are taking their lives

#193

Post by bitcurious »

doublesCs wrote: post #130
CathedralBorrow wrote: post #123

Earlier quoted context omitted.

Why are you wasting all these words on something that is not at the top of your sorted list? What is the most important problem in the world?

> Why are you wasting all these words on something that is not at the top of your sorted list? I wrote that out of curiosity about why such an article would end up on the front page of HN. Yes, I understand that HN isn't just business and tech, it's "interesting things" - but why is this article interesting? Since I don't find it interesting, maybe some people found this an important issue, I thought?

>I wrote that out of curiosity about why such an article would end up on the front page of HN.

(a) It's a well written and interesting article on a sports issue that most don't know about.

(b) Its TBI implications are generalizable to a lot of popular activities.

Re: Sledding athletes are taking their lives

#194

Post by bo1024 »

VLM wrote: post #155
Invictus0 wrote: post #141

Earlier quoted context omitted.

I don't understand this comment; what is physically bad about running? I'll accept that you may have a higher rate of injuries but surely we can agree that pulling a muscle and giving yourself Parkinson's are not remotely in the same ballpark of injuries.

Knee implants, significant negative hormonal changes for men over 50 miles/wk. Repetitive stress injuries are no joke. OP is probably not aware that the Olympics does not have ultra-marathon type events which are generally very unhealthy for participants, only a 10K and a marathon (and shorter sprints of course)

> Knee implants

Source? I would expect these are much more common in obese people than in habitual runners. My understanding is that runners have been found to have healthy knees, e.g. with a bit of googling I find [1][2] (but haven't read them).

> significant negative hormonal changes for men over 50 miles/wk

They have found somewhat lower testosterone levels, but I don't know of any study finding negative health impacts. Do you have a source for "significant negative"?

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5179322/ [2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2556152/

Re: Sledding athletes are taking their lives

#195

Post by AnIdiotOnTheNet »

erfgh wrote: post #188
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…

How about we let people decide on their won what they want to do with their lives?

Generally I'd agree, but there is some rationality to the idea that we should not encourage and promote certain activities because of their inherent dangers. Smoking, for instance.

Re: Sledding athletes are taking their lives

#196

Post by def_true_false »

skizm wrote: post #176
Invictus0 wrote: post #171

Earlier quoted context omitted.

WRT knee damage, I found a Harvard report saying that running helps protect your knees against arthritis [0]. You'll have to source your own hormonal claim because it was too vague for me to find much, but what I did find did not seem negative [1][2]. [0] https://www.health.harvard.edu/healthbeat/will-continuing-to... [1] https://pubmed.ncbi.nlm.nih.gov/19046725/ [2] https://pubmed.ncbi.nlm.nih.gov/18208421/

That first link is just a Q/A. There is no study or report linked. Almost all studies use untrained vs trained athletes. They rarely qualified what "trained" means and could be anything from a lifetime athlete to someone who self-reported following a 6 week plan prior to the study and now we consider this person "trained". Most athletic studies are used to compare a sedentary person to someone who workouts casually (…

Yeah, you definitely have to sacrifice parts of your overall health if you want to exercise more than 90 minutes per day.

/s

Diminishing returns doesn't mean that you have to sacrifice anything (besides some idealized notion of efficiency). The hurt-your-overall-health point is somewhere much closer to Olympic athlete than it is to 10hrs/week. If you just vary the activities a little, you will have no trouble with spending a lot more time on exercise. People who literally do only the one physical activity they compete in are straw men.

PS: The number of people completely clueless about fitness on HN would be hilarious if it weren't so sad.

Re: Sledding athletes are taking their lives

#197

Post by def_true_false »

TheRealSteel wrote: post #177
stefs wrote: post #124

Earlier quoted context omitted.

honnold may be a special case. his capabilities of dealing with risk and fear are exceptional.

I'd say it's partly that, but more a case of survivorship bias; we don't hear from other solo free climbers because most of them are dead.

citation needed

Edit: It's not like these climbers never climb with gear. That is, they don't have to confront the learning curve and fatal consequences at the same time. They can also learn safely via bouldering, climbing above water and such.

Re: Sledding athletes are taking their lives

#198

Post by mrfredward »

willis936 wrote: post #136
etrautmann wrote: post #41

Earlier quoted context omitted.

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 m…

What would you say is the maximum frequency that the helmet is coupled to the head at? Filtering is a trivial operation and I would expect the g forces felt by sledders to be sustained for the better part of a second. You lose a lot of fidelity, but if you’re still over the line then you know there’s a problem.

According to the article, the tracks are designed for sustained g-forces of 5Gs. These are the accelerations that are sustained for greater than a second. According to the annotations on the NYT's plot, the g forces which are most alarming are from when the helmet makes contact with the ice. This is precisely when the helmet accelerations would be expected to differ wildly from what the head is actually doing.

A low pass filter could easily be used to remove the impacts with the ice, but minus the impacts with the ice there's nothing in that acceleration trace that should be alarming for a professional athlete. The high frequency content is the concern here.

Re: Sledding athletes are taking their lives

#199

Post by simonh »

tzs wrote: post #185
toyg wrote: post #107

Earlier quoted context omitted.

> it might have taken until 2013 for someone to measure its g force To be fair, measuring this sort of thing was pretty hard in the past, when cheap miniaturized sensors and memory didn't exist. I expect we will see more and more activities being re-evaluated now that tech is easily wearable.

Could you do it photographically? If you can photograph the head movements at a high enough frame rate, you should be able to calculate the acceleration that produced those movements.

It's about pressure and load, not movement. Also the sleds vibrate and shake enormously. Any method of measuring this has to be extremely precise, and also extremely responsive to changes over extremely short time frames to capture every vibration and shake in many different axes of freedom simultaneously. Before modern motion sensors I just don't think there was any way to do it.

Even if motion was enough, which I'm sure it isn't, film only captures a flat image from a fixed point, or the camera is moving itself so you have to compensate for that. Springs and wires suggested by others have way too much hysteresis to cope with the extremely rapid vibrations and changes in orientation.

Re: Sledding athletes are taking their lives

#200

Post by yk »

tzs wrote: post #185
toyg wrote: post #107

Earlier quoted context omitted.

> it might have taken until 2013 for someone to measure its g force To be fair, measuring this sort of thing was pretty hard in the past, when cheap miniaturized sensors and memory didn't exist. I expect we will see more and more activities being re-evaluated now that tech is easily wearable.

Could you do it photographically? If you can photograph the head movements at a high enough frame rate, you should be able to calculate the acceleration that produced those movements.

When you are looking for something like 80g (as is the maximum of the graph), then the head would move something like 4 cm between two frames, which suggests to me, that you probably want to have a lot more than 100 fps, since you want to get a good handle on the highest accelerations.

On the other end of the scale, the positional error from the camera sensor is something like

  width of frame / horizontal resolution
which should give you something in the mm range, and it seems possible to get head tracking in the same order of resolution, which should limit your acceleration measurement for low acceleration.

Overall, probably doable but you are replacing a 30c accelerometer with a multi year research project.

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