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

Is a 'slow' swimming pool impeding world records?

sports.yahoo.com

Post reply on HN
Print view View original

41–50 of 344 posts

Re: Is a 'slow' swimming pool impeding world records?

#41

Post by sshine »

defrost wrote: post #18
School-Cotton wrote: post #12

Earlier quoted context omitted.

Why does it matter how deep the pool is? Edit: the article addresses this, so if anyone else is curious like I was, I suggest clicking.

If it's too shallow the swimmers arms hit the bottom ... Slightly deeper and there's drag from the floor as their arms barely miss it. That effect persists until it doesn't .. now it's deep enough. It needs to be deep enough that vortex's created by swimmers have disapated by the time they reach bottom and reflect back to the surface so as to not interfere with following swimmers or swimmers returning.

> If it's too shallow the swimmers arms hit the bottom

Is it’s deep enough, the gravitational mass of the water will form a black hole and squash the swimmer to death.

Re: Is a 'slow' swimming pool impeding world records?

#42

Post by echoangle »

boringg wrote: post #30
echoangle wrote: post #25

Earlier quoted context omitted.

Being good at swimming doesn’t mean you can evaluate the pool performance better than everyone else. I trust someone running a CFD analysis of a pool more than a competitive Olympic swimmer when it comes to the effect of pool depth. It’s very hard to make accurate statistical assessments from intuition. Edit: maybe I’m not making myself clear: I don’t doubt they are slower in the current pool than they were before. B…

While part of it may be true. The athletes who spend 1000s of hours can probably intuit something being different.

The can maybe intuit being slower, but I doubt they can accurately tell you that it’s because of a different pools depth. There are a lot of other variables that could be the reason.

Re: Is a 'slow' swimming pool impeding world records?

#43

Post by MrPatan »

echoangle wrote: post #25
lou1306 wrote: post #23

Earlier quoted context omitted.

But a lot of the swimmers themselves are not able to go anywhere near their personal bests: this is a sharp reversal from past Olympics, where many athletes reached new personal records. Plus, they are the worldwide foremost experts on competitive swimming. Definitely I would be more interested in their evaluation of a swimming pool rather than trust "research results" from the company that built the pool in question…

Being good at swimming doesn’t mean you can evaluate the pool performance better than everyone else. I trust someone running a CFD analysis of a pool more than a competitive Olympic swimmer when it comes to the effect of pool depth. It’s very hard to make accurate statistical assessments from intuition. Edit: maybe I’m not making myself clear: I don’t doubt they are slower in the current pool than they were before. B…

Intuition forms because it works. When it doesn't it's remarkable to the point of writing books and movies about it.

Re: Is a 'slow' swimming pool impeding world records?

#44

Post by echoangle »

Xcelerate wrote: post #33
echoangle wrote: post #25

Earlier quoted context omitted.

Being good at swimming doesn’t mean you can evaluate the pool performance better than everyone else. I trust someone running a CFD analysis of a pool more than a competitive Olympic swimmer when it comes to the effect of pool depth. It’s very hard to make accurate statistical assessments from intuition. Edit: maybe I’m not making myself clear: I don’t doubt they are slower in the current pool than they were before. B…

I trust the swimmers’ intuition far more than an ad-hoc CFD analysis. Plus the shape of the pool itself isn’t necessarily the only variable that might be affecting the race times. The gold standard would be an empirical randomized controlled trial to compare two pools, assuming you could hide “which pool” from the participants.

I don’t doubt that they are slower, I doubt that it’s the pool depth. To be more accurate, i have no idea if it the pool depth, but a swimmer saying that it is doesn’t tell me a lot. I’m not sure if the intuition of a swimmer can differentiate between the pool depth effect and other effects that could influence performance. I don’t doubt that something is making them slower, but i don’t believe it’s pool depth until there’s better evidence.

Re: Is a 'slow' swimming pool impeding world records?

#45

Post by Eddy_Viscosity2 »

CoastalCoder wrote: post #28
echoangle wrote: post #25

Earlier quoted context omitted.

Being good at swimming doesn’t mean you can evaluate the pool performance better than everyone else. I trust someone running a CFD analysis of a pool more than a competitive Olympic swimmer when it comes to the effect of pool depth. It’s very hard to make accurate statistical assessments from intuition. Edit: maybe I’m not making myself clear: I don’t doubt they are slower in the current pool than they were before. B…

Even CFD analysis is a model though, with all that implies. Would a large, blind empirical study be more trustworthy?

Yes and no. The empirical study could identify correlations and the strength of those correlations, but does nothing to say why they are correlated (maybe just spurious). But a CFD analysis may give you insight into what may be happening to cause the issue, which can then lead to a hypothesis that can then be tested further. All models are wrong, but some are useful.

Re: Is a 'slow' swimming pool impeding world records?

#46

Post by _heimdall »

echoangle wrote: post #39
_heimdall wrote: post #29

Earlier quoted context omitted.

You don't necessarily need to do an in depth study of the pool when every Olympic swimmer in it fails to meet their own personal records. A study may be useful to understand why depth still matters beyond the 2m point, but a study isn't needed to show that swimmer performance is impacted.

Or maybe there’s something else going on? There are a lot of other variables in a pool except depth, no? Maybe water tension, density, viscosity? Someone else mentioned the walls of the pool also influencing the wave properties in the pool. Just noticing the pool being more shallow and people swimming slower doesn’t mean that’s the reason.

Rereading your last comment and I think I just misunderstood it, sorry! I first read it as saying a study would be needed to know if something about the pool was anything them down, but you were still specifically talking about whether the depth is the issue.

Re: Is a 'slow' swimming pool impeding world records?

#47

Post by echoangle »

_heimdall wrote: post #46
echoangle wrote: post #39

Earlier quoted context omitted.

Or maybe there’s something else going on? There are a lot of other variables in a pool except depth, no? Maybe water tension, density, viscosity? Someone else mentioned the walls of the pool also influencing the wave properties in the pool. Just noticing the pool being more shallow and people swimming slower doesn’t mean that’s the reason.

Rereading your last comment and I think I just misunderstood it, sorry! I first read it as saying a study would be needed to know if something about the pool was anything them down, but you were still specifically talking about whether the depth is the issue.

Yes, I think a lot of people misunderstood the point, I’m ESL so maybe i didn’t write it up properly. I was just talking about the effect of pool depth, not doubting that something is different this time.

Re: Is a 'slow' swimming pool impeding world records?

#48

Post by chatmasta »

dist-epoch wrote: post #38
hgomersall wrote: post #14

Earlier quoted context omitted.

Supposedly, that's why the fastest qualifiers get the middle lanes.

[flagged]

If you put them in the slow lanes then there would be an incentive to place poorly in qualifying rounds.

Re: Is a 'slow' swimming pool impeding world records?

#49

Post by derbOac »

croes wrote: post #15
samldev wrote: post #5

I was a college swimmer, qualified for Olympic Trials in 2012 and 2016. There are absolutely slow and fast pools. It basically comes down to two things: 1. The depth - which is only 7ft in Paris, unusually shallow for a competition pool. 2. The sides. Does the water spill over the sides into the gutters, or smash into a wall and bounce back, creating more chop. A trained eye can see all the swimmers in Paris struggli…

>A lot of this is perception vs. reality,” he said. “If you were to talk to many very accomplished coaches, they would say the pool has to be a minimum 3 meters deep. Most of our research shows that anything over 2 meters is frivolous. … Obviously, some depth is very important. But after a certain point, it's diminishing return. Maybe it's just the swimmers and not the pool as such

At the end of the article it notes thqt quote is coming from the company who built the pool.

On some swimming forums competitors were complaining about the bidding process for the pool construction and giving a different opinion, noting that the depth is less than what was recommended by international standards bodies. There's also something about video equipment at the bottom of the pool?

I'm not sure what to think, as there are things to consider both ways, but there's a bit more out there than swimmers versus pool officials.

Post reply on HN