Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Running Speeds

allendowney.com

Post reply on HN
Print view View original

31–40 of 195 posts

Re: Running Speeds

#31

Post by tgv »

codeflo wrote: post #13
tgv wrote: post #5

Earlier quoted context omitted.

This article is bollocks, though. It's a fit of highly unrepresentative data, not even a good one, but worse: it doesn't explain anything. If you take that model seriously, Usain Bolt could have been anybody in the entire history of mankind.

> If you take that model seriously, Usain Bolt could have been anybody in the entire history of mankind. No model is perfect, but I don’t have the slightest clue why you think that would follow.

Because it fits by multiplying random variables. It cannot explain why records are improving, i.e. why Usain Bolt didn't live 100 years ago.

Re: Running Speeds

#32

Post by wjholden »

onetimeuse92304 wrote: post #15
PaulKeeble wrote: post #11

I used to like watching the Special forces selection process TV shows. They would claim that mostly people failed due to mental fortitude. The problem was repeatedly in these shows you would see people who weren't fit enough, whose muscles were not capable of the physical strength and stamina necessary to push like this. Many had trained very hard and were in very good shape but they just couldn't sustain it in the c…

Yes, the mental fortitude is much overblown aspect. Yes, there is this thing as mental fortitude and you can even train it to persist to run hard, especially when you "kick" at the end of a race. But this only helps to a very small degree, the most of the result is due to more mundane aspects like your experience with running, your running efficiency, your aerobic capacity, your additional fat you are carrying with y…

Your observation on neurological efficiency generalizes to all physical activities.

If you practiced pull-ups every day, you would become very efficient at pull-ups and possibly double the number you can do. At the same time, it isn't impossible for seemingly related measurements of strength (such as the biceps curl and deadlift) to get worse as your body "overfits" its adaptation to the pull-ups.

Re: Running Speeds

#33

Post by Beijinger »

PaulKeeble wrote: post #11

I used to like watching the Special forces selection process TV shows. They would claim that mostly people failed due to mental fortitude. The problem was repeatedly in these shows you would see people who weren't fit enough, whose muscles were not capable of the physical strength and stamina necessary to push like this. Many had trained very hard and were in very good shape but they just couldn't sustain it in the c…

Reminds me of the movie Gattaca https://www.imdb.com/title/tt0119177/

Anton Freeman : Vincent! How are you doing this Vincent? How have you done any of this? We have to go back.

Vincent : It's too late for that. We're closer to the other side.

Anton Freeman : What other side? You wanna drown us both?

Vincent : You wanna know how I did it? This is how I did it Anton. I never saved anything for the swim back.

Vincent : There's no gene for fate.

Re: Running Speeds

#34

Post by jmmcd »

wjnc wrote: post #3

If your high school math would only consist of working through the various books of Allen Downey you would get a very rigorous, basic introduction to: programming, computer science, statistics, computational and Bayesian thinking and a lot more. You could write and compare simple to intermediate programs in many programming languages, where you’d have experience in implementing the same structures in different langua…

I'm a big fan of Downey but this article is quite far from his best.

1. The data he fits is for distance (10k), and the conclusion ("why you can't beat the Freeze") concerns sprinting.

2. The claim that speed is a multiplicative model is fine and I agree based on the 10k data. But the people running against the Freeze aren't uniform from the population, so the argument is missing a step about what distribution (what percentile of the background distribution) they might be from.

3. There are some interesting numbers about how the high school girl is x% faster than Downey, the boy is y% faster than the girl, etc, but they don't link to the stats later in the article.

Re: Running Speeds

#35

Post by alexmolas »

leto_ii wrote: post #9

I'm not sure this analysis is as surprising or meaningful as it might seem at first sight. In the end I think what this tells us is that in the general population there are many distinct subpopulations with different distributions of running speed. I would expect that if you start conditioning on things (e.g. gender, age, level of fitness) things start looking a lot more normal, rather than log-normal. You might not…

If I'm not wrong you can't obtain a lognormal as a mixture of Gaussian distributions. The processes that generate these distributions are completely different. Gaussian distribution arise when the factors are additive, and lognormal when factors are multiplicative, so these are two completely different distributions. The same way I don't think you can get a normal distribution just by conditioning on an exponential distribution.

Re: Running Speeds

#36

Post by gadders »

I think people don't realise how large differences in ability can be.

We recently had a friend of my daughter's at my house who was (at the time) 14, barmy 6ft tall and threw javelin for the UK county..

We took it in turns throwing a ball for my dog and it was like she had a ball launcher built into her arm.

Re: Running Speeds

#38

Post by Aeolun »

jmmcd wrote: post #34
wjnc wrote: post #3

If your high school math would only consist of working through the various books of Allen Downey you would get a very rigorous, basic introduction to: programming, computer science, statistics, computational and Bayesian thinking and a lot more. You could write and compare simple to intermediate programs in many programming languages, where you’d have experience in implementing the same structures in different langua…

I'm a big fan of Downey but this article is quite far from his best. 1. The data he fits is for distance (10k), and the conclusion ("why you can't beat the Freeze") concerns sprinting. 2. The claim that speed is a multiplicative model is fine and I agree based on the 10k data. But the people running against the Freeze aren't uniform from the population, so the argument is missing a step about what distribution (what…

To be fair, you don’t really need any of the numbers in the article. If the only thing you know about the freeze is that he’s 1.5 seconds slower than Ursain Bolt on the 200 meters you can conclude that he’ll win basically any race he runs.

Re: Running Speeds

#39

Post by suavesito »

tgv wrote: post #31
codeflo wrote: post #13

Earlier quoted context omitted.

> If you take that model seriously, Usain Bolt could have been anybody in the entire history of mankind. No model is perfect, but I don’t have the slightest clue why you think that would follow.

Because it fits by multiplying random variables. It cannot explain why records are improving, i.e. why Usain Bolt didn't live 100 years ago.

It can explain it. Better training and better equipment are (at least) two variables that improve people timings. Maybe a century ago there was an Usain Bolt, just didn't had neither the proper training, nor equipment, and those low factors avoided better timings.

Re: Running Speeds

#40

Post by lordnacho »

I've often wondered how exactly I might increase my sprint speed, in terms of form. I've never met a sprint trainer, so all I can do is just try to naturally sprint, but I'm clearly not very fast and never was. But somehow I don't even know what the fundamentals are. What do you need to do to be fast?

The other amazing thing is that marathon runners seem to be faster than I can sprint, and I really don't get how they maintain it. If I could just sprint that speed, I would be going pretty fast.

Post reply on HN