After seeing a woman break 24 seconds and I think we can stop the discussion of "IF" the LZR suit is faster and start thinking "how much faster".
The previous line of suits (Fastskin and so on) were pretty similiar to a shaved swimmer. Sure - they do feel like they make you float, but overall the times seemed to move along "in line" with what I would expect to see in terms of improvements in the sport. If the previous suits would have been that much faster than shaving, you would have never seen people just using the legskins. By the way - for us Masters swimmers there was always the added benefit of keeping in all the "extra layers of skin".
So how much faster are the LZR suits ?
If I had to guess based on the results so far, I would say 0.25 to 0.30 per 50 and double that for the 100. I can see the Bernard going 48 low in the 100 and I can see Sullivan getting close or just breaking the 50 record. It makes sense that Libby Lenton would swim a 24.2 or so in the 50.
I think one of the top regular teams out there should do a test - you need a good amount of world class swimmers training together to be able to do a test. Here is the test I would propose:
8-10 swimmers
2 days of testing
4x50 on 10 minutes all out
Day 1 - swim 2 with a Fastskin2 followed by 2 with the LZR
Day 2 - swim 2 with the LZR followed by 2 with the Fastskin2
Get the averages of all 10 swimmers - maybe drop the high and low and there you go.
Why do the test ? I would HAVE to know. Swimming is a big part of your life and you just set a massive PR using this new technology - my very first question would be " How much was me and how much was the suit?"?
Former Member
I think people often confuse "proof" with "probability" The argument here is not whether or not the LZR with 100% certainty increases speed, at least I don't think it is. It's a question of probabilities. There is a reality out there somewhere, would you really bet someone, even money, that the LZR suit doesn't improve performance (not due to mental/placebo aspects) ?? I doubt it.
That's your opinion, but that's all it is, sorry.
I don't have to argue a thing, the burden of proof is on those who claim a significant and large improvement to prove their case. Gather your data, analyze it and submit it for peer-reviewed publication if you think you have done so.
(I'm about to go way off topic.)
Chris,
Statistical significance testing gives information on the probability of a Type I error only under the assumption that the null hypothesis is true, which is quite different from saying that it gives the probability of a Type I error given a certain set of results.
I'll give an example to illustrate the difference. Say I create an experiment to find the effect of suit color on swim performance. I have one group of swimmers that wears green old school briefs, and another group that wears blue old school briefs. The green group swims faster than the blue group, with p's the probability that green suits cause people to swim faster than blue suits? It's damn near close to zero, because there's no reason at all to believe that green speedos make people swim faster. It's not, as you appear to be suggesting, 95%. That number, rather, represents how often we will get a time difference smaller than the one we got if we repeated the experiment several times.
I think that what Chris proposed was to set up an experiment and test the null hypothesis that "the suits have no effect" and use a straight frequentist approach to analyzing the data. Given that framework, he's not wrong.
You seem to be arguing some other Bayesian interpretation, maybe based originally on the numbers given by hoch. You and he are arguing two quite different approaches.
Probably it is much easier to objectively evaluate whether the suit reduces drag than whether it improves times, you don't need the whole taper/training/mental control, just take measurements with and without.
I wonder, if it was completely totally convincingly proven that the suits gave no benefit at all beyond the placebo effect whether the whole world would start swimming slower again...
I'm taking exception to this:
There's no such thing as scientific certainty
I realize that; hence the quotes and the statement that it is all about probabilities.
Oh, and Mike is quite correct.
This statistics mumbo jumbo makes me dizzy. All I know is if I don't swim faster on Saturday than I did last year, the suit is no good! Never mind the umpteen independent variables that might effect the analysis. I have a 50 *** title to defend, and it's all riding on the B70. Emotion over logic. :rofl:
Gaash...of course it is about probabilities. That is the entire basis of hypothesis testing, which is what we are really talking about. The bar for "scientific certainty" is commonly taken to be 95% probability, meaning a 5% chance of a false positive (in this case, incorrectly assuming the LZR has an effect when it really doesn't).
There's nothing special about the 5%, really. You're referring to a p-value, right? That doesn't give you the probability of a false positive, it gives you the probability that, due to random variation, an effect size as large as the one found in a sample would occur if the actual effect size were zero. Each time you compute a p-value with a sample, it says nothing about the probability that the effect is real unless you factor in your prior probability belief that it is real, based on prior data and reasoning about the mechanisms involved in the effect.
Of course, there are no studies, so there are no effect sizes or p-values to interpret.
Who has the financial motivation to do a really scientific study?
Coaches and professional swimmers, to name two groups. USA-S or USOC ought to be funding this. If US swimmers who wear legskins or jammers are truly throwing away a significant advantage, wouldn't it be good to know about it? Rather than just making what amounts to educated guesses?
I'm sure there are any number of exercise physiologists and others who would be willing to do the study. I've seen scientific studies on the effects of wetsuits on swimming speed, for example.
It isn't easy because there are a lot of factors that might potentially affect the degree of performance enhancement (if any): body type, swimming speed, stroke, course (long course vs short course), and stroke mechanics, to name a few. Also, I think the best expts would be under true race conditions with tapered/shaved athletes.
(I'm about to go way off topic.)
Chris,
Statistical significance testing gives information on the probability of a Type I error only under the assumption that the null hypothesis is true, which is quite different from saying that it gives the probability of a Type I error given a certain set of results.
I'll give an example to illustrate the difference. Say I create an experiment to find the effect of suit color on swim performance. I have one group of swimmers that wears green old school briefs, and another group that wears blue old school briefs. The green group swims faster than the blue group, with p's the probability that green suits cause people to swim faster than blue suits? It's damn near close to zero, because there's no reason at all to believe that green speedos make people swim faster. It's not, as you appear to be suggesting, 95%. That number, rather, represents how often we will get a time difference smaller than the one we got if we repeated the experiment several times.
