> The problem in the research community is that scientists have little incentive to duplicate earlier work just to check if it’s correct. Many journals have explicit policies forbidding the publication of work that attempts to replicate previous experiments.
This drive for unending novelty in the sciences is a shame on many levels. The good and useful work of duplicating and verifying results goes undone, and scientists are driven ever more forcefully towards designing studies only on the basis of what will attract grant agencies.
Duplicating major results carefully would be useful to the scientific record. Trying things that will probably fail, and then publishing negative results, would be useful too. But, for most researchers, doing this useful work appears to be career suicide.
The Specialized video[1] is worth watching - it's pretty funny how astonished they were over how much power it saved.
If you are interested in this, then the book Faster: The Obsession, Science and Luck Behind the World's Fastest Cyclists by Michael Hutchinson is really good (and very well written).
He notes that human intuition about aerodynamics just isn't very good (you have to test) and that the current state of the art is no longer wind tunnel testing but computational fluid dynamics (CFD) followed by testing with a power meter on the road.
CFD lets designers iterate much quicker on designs and try things outside the norm (avoiding the local maxima problem). Power meters plus riding is better than wind tunnel testing because things like variable cross winds are very hard to test in wind tunnels.
The annoying thing with CFD with analyzing viscous phenomena is the question of reproducibility. Flow structures in this regime (low Re, that is low speed and small length scales) are notoriously sensitive to surface defects, e.g. the hairs being analyzed. A CFD sim will show nearly the same results for a given problem, and current CFD lacks the fidelity to really model tiny turbulent features at these scales as well as the necessary fine surface definition. Experimental results may show drastically different results depending on the minute upstream flow variations, and surface quality: in this case, legs with hair/sweat/dust/oils could all trip the boundary layer to varying degrees. Stories abound of clumsy wind tunnel technicians who left skin grease on a wing model for a low-speed test and neglected to polish it with a rag...
I had thought that it was already established by swimmers that hair was a detriment to speed. Why would it be surprising to cyclist? I do ride, but not competitively so I will keep the razor to my face only, thank you.
One thing they don't tell you in the Specialized video is that they're not testing someone who is pedaling. There's some much more turbulence from just moving your legs, that shaved or not shaved makes almost 0 difference. No one is coasting for 40 km. Even the time savings they do cite in perfect, almost platonic conditions is seconds over hours of riding.
Bicycling manufacturers always skew the numbers for how much savings (time, watts, whatever) their new top of the line frames will give you. It's all smoke and mirrors.
Exactly. I'm an active racer and have witnessed people get yelled at in the medic tent for not shaving their legs. Treating road rash is awful with leg air.
What's interesting here is that the practice of cyclists doing so goes back a century. By contrast, the fashion of women shaving their legs dates back primarily to around World War II, and the influence of pinup model Betty Grable. See: http://www.straightdope.com/columns/read/625/who-decided-wom...
The gremlin that is low Re, viscous drag. This is how cacti work; the needles slow surrounding air to reduce moisture loss through convective evaporation.
Previous test: "leg-shaving reduced drag by 0.6 per cent"
New test: "The tests showed that shaving his legs reduced Thomas’s drag by about 7 per cent"
Yet the blurb says: ''Even more confounding was that the results contradicted earlier finding''. What's contradictory about those results? Be it 0.6% or 7%, shaving your legs clearly reduces drag.
I believe that was a reference to the "insignificant difference" claims. 0.6% wasn't seen as significant enough difference so it became a "fashion choice" rather than an efficiency one.
I find it odd that they only report the results in percent in the first place. Maybe the baseline drag of a rider back in the 80's was much higher than today, making 0.6% old the same amount of force as 7% new.
a family friend, the aerodynamicist Chester Kyle, was mentioned in this article. He was a lecturer at Long Beach State (I think) and did practical wind-tunnel testing with my father (an engineer and manufacturer) on bicycle shapes for many years.
He pushed the edges of conventional design, and participated in the human powered vehicle races quite a bit.
That's fantastic; I never thought I would hear about him on here.
It bugs me that the test is run with the vertical wheel supports in place. It's conceivable that they alter airflow in a way that affects how it goes over the cyclists legs.
Interesting, I wonder how dramatic the effect is with swimming, there are swim flumes like this https://www.youtube.com/watch?v=feUhyCklHL0. It's usually used to analyze your stroke, but maybe if you put a bar in there to hold on to and test unshaven vs. shaven.
As a former swimmer, I can say that shaving is not only done for drag. Once shaved and in the water, even while casually swimming in warmup, I would feel as if I'm actually floating better. We'd call the "feel for the water" or something similar. It's hard to describe unless you've experienced it, but I suppose it has something to do with a newly exposed layer of skin in contact with the water.
And, of course, there are also the benefits of less drag and psychological placebo effect.
As a former national-level swimmer, I always shaved my legs/arms and tapered my training for a big meet twice a year.
I found that combination to lower my times by about 1 second per 50m, or about 5%. I don't know how much of that is attributable to the shaving, but I will say it helped me "feel" way faster.
Summary: a team at Amgen discovers 47 of 53 "landmark" studies published in high-quality journals could not be reproduced. A team at Bayer did an internal review of programs they had initiated based on journal studies and found that less than a quarter of those findings could be reproduced.
Three very damning quotes:
"Some authors [of the journal articles] required the Amgen scientists sign a confidentiality agreement barring them from disclosing data at odds with the original findings."
"'We went through the paper line by line, figure by figure,' said Begley. 'I explained that we re-did their experiment 50 times and never got their result. He said they'd done it six times and got this result once, but put it in the paper because it made the best story. It's very disillusioning.'"
"The problem goes beyond cancer. On Tuesday, a committee of the National Academy of Sciences heard testimony that the number of scientific papers that had to be retracted increased more than tenfold over the last decade; the number of journal articles published rose only 44 percent."
Academics are pressured to produce publications, not to produce science, and their studies are not always rigorous (not blinded to experimenters, etc.). People with high integrity and ability do produce good science that gets published, but unfortunately that appears to be the minority, even in highly prestigious journals.
So I'm curious: how would you fix it?
One thing the article mentions that might improve things is every journal dedicating one complete issue a year to reproducing the most influential studies of the year. Another could be getting a consortium of pharmas (who try to reproduce studies all the time, because if you're going to successfully make drugs you need the thing to work) to publish their internal data for the benefit of all. Does something like that exist?
I think it's healthy that this discussion expresses amazement, skepticism, methodological questions, and observations about competition for public media attention, and frequent instances of journals cynically manipulating publication for maximal sensationalism under a scientific patina.
Strictly my own imagination, but I'm anticipating the introduction down the road of the world's most advanced hair removal system that gives cyclists a big aerodynamic advantage proven by scientific tests. Yes buy the XYZ system and fly to victory! Wow, I really am jaded, but too many times we've seen it happen.
So much bad science obscures the good work because the latter doesn't make the news, it's far too boring to attract attention. It's the small incremental, tedious, repetitious, careful, persistent work that provides the real advances. Edison I think said, "we find 20,000 ways it doesn't work" and learn something every time we try.
I propose a simple set of remedies. Journals should give highest priority to publishing careful replications of prior studies, whether it's yes/no/maybe. Negative studies whether original or replications are give as much priority and those confirmatory. Novel associations are of course welcome if meeting standards of adequate power to discern something beyond quirky results.
Ultimately, the impact of hyperbolic claims about the meaning of research causes the greatest distortions of scientific process and progress. Journal editors can solve the great bulk of misinformation their journals promulgate. It's remarkably simple. All they have to do is issue an edict, all that authors can write about are the history, background, what they did and factual results of their work. These "rules" apply to observational and experimental work all the same. IOW it would be forbidden to draw conclusions about the what the outcomes mean, what is proven, or what "causes" what.
Sure giving context about past results is necessary and usefully informative, but conclusions are for we the readers to determine. If this was the case, suddenly the strident "answers" and premature incorporation of findings into practice will be sharply reduced. Hysteria will subside. We can then actually use our scientific talent to accomplish honest goals, and solve the real and daunting problems we actually have.
Perhaps this seems a radical view and maybe it is. It's not whether I'm right or anybody will make any of these substantial changes. It is about getting back to careful thoughtful scientific inquiry and reducing misdirected human energies.
I speculate here that this could be a second reason why we lost our big ape hair. The preferred method of hunting was running after prey until it fell/slowed down - due to the fact that, unless other animals, man can run and hold the mouth open, thus eliminating the excess heat + higher oxygen flow. Having less hair than the prey made us run otherwise faster while on lower enery requirements.
At the speed we run, it would make no difference I would imagine. The benefits of shaving your legs only really come into effect for cyclists at the pro level ... those of us who can manage a steady 25km/h see far less benefit.
I always thought it was an urban myth that it made you go faster, and that the real reason was that road rash was easier to treat.
Shaving your legs doesn't take much time at all. I race a few times a week (during the season) and shave once, at most twice, a week. Probably takes 10 minutes to shave. There's nothing I could do for 10 minutes a week that would improve my time by up to eight percent (most amateur cyclists already overtrain as it is). Not part of your question, but shaving is also largely about being able to treat road rash and avoid infection.
They are claiming "it contradicts previous results", but certainly the savings must depend on the athlete's pre-shave hirsuteness. Unless they controlled for that, the previous results could have just been because of a relatively smooth group of subjects.
The article states that the previous results didn't involve any subjects at all, but a "fake lower leg in a miniature wind tunnel with or without hair glued onto it".
Compared to numbers from earlier studies (0.6), the new number (7) looks suspiciously like a floating point error arising from software/hardware issues!
The number of people needed to archieve statistically significant results more or less solely relies on the size of the effect that gets measured[1]. It's actually not unusual to design experimental studies with just a single person - provided the "treatment" (shaven legs in this case) are reversible. Then you just have to make repeated phases with and without treatment , e.g. ABABAB or even ABACABAC if you have an alternative treatment you want to compare the results with.
[1] If you design a study you can actually start from the other end: If you can estimate the size of the effect to be measured, you can calculate the number of people needed for significance beforehand.
Massage and reducing wear-and-tear in event of crashing are the best most plausible reasons I've heard for it. I'd never heard anybody seriously thinking it reduces drag in a meaningful way.
(Edited to describe my experience, per "let's not read the article" comment).
[+] [-] sjackso|11 years ago|reply
This drive for unending novelty in the sciences is a shame on many levels. The good and useful work of duplicating and verifying results goes undone, and scientists are driven ever more forcefully towards designing studies only on the basis of what will attract grant agencies.
Duplicating major results carefully would be useful to the scientific record. Trying things that will probably fail, and then publishing negative results, would be useful too. But, for most researchers, doing this useful work appears to be career suicide.
[+] [-] nl|11 years ago|reply
If you are interested in this, then the book Faster: The Obsession, Science and Luck Behind the World's Fastest Cyclists by Michael Hutchinson is really good (and very well written).
He notes that human intuition about aerodynamics just isn't very good (you have to test) and that the current state of the art is no longer wind tunnel testing but computational fluid dynamics (CFD) followed by testing with a power meter on the road.
CFD lets designers iterate much quicker on designs and try things outside the norm (avoiding the local maxima problem). Power meters plus riding is better than wind tunnel testing because things like variable cross winds are very hard to test in wind tunnels.
[1] https://www.youtube.com/watch?v=DZnrE17Jg3I
[2] http://www.amazon.com/Faster-Obsession-Science-Fastest-Cycli...
[+] [-] nether|11 years ago|reply
[+] [-] Shivetya|11 years ago|reply
[+] [-] idlewords|11 years ago|reply
[+] [-] justinator|11 years ago|reply
Bicycling manufacturers always skew the numbers for how much savings (time, watts, whatever) their new top of the line frames will give you. It's all smoke and mirrors.
[+] [-] jmadsen|11 years ago|reply
We shave because it helps reduce road rash when you go down on asphalt (slide easier) & easier to keep the wounds clean afterwards.
[+] [-] AndrewKemendo|11 years ago|reply
A bit of it is also in-group/out-group signaling.
[+] [-] andygates|11 years ago|reply
"Reduce drag" is always the jokey reason I'd use for non-cyclists :)
[+] [-] pdxandi|11 years ago|reply
[+] [-] jaynos|11 years ago|reply
[+] [-] erbo|11 years ago|reply
[+] [-] nether|11 years ago|reply
[+] [-] jpatokal|11 years ago|reply
New test: "The tests showed that shaving his legs reduced Thomas’s drag by about 7 per cent"
Yet the blurb says: ''Even more confounding was that the results contradicted earlier finding''. What's contradictory about those results? Be it 0.6% or 7%, shaving your legs clearly reduces drag.
[+] [-] UnoriginalGuy|11 years ago|reply
[+] [-] Too|11 years ago|reply
[+] [-] ssanders82|11 years ago|reply
[+] [-] serf|11 years ago|reply
He pushed the edges of conventional design, and participated in the human powered vehicle races quite a bit.
That's fantastic; I never thought I would hear about him on here.
[+] [-] idlewords|11 years ago|reply
But maybe I don't fully understand the experimental setup. I'm basing my comments on what I see in https://www.youtube.com/watch?v=DZnrE17Jg3I
[+] [-] andyjsong|11 years ago|reply
[+] [-] shiloa|11 years ago|reply
And, of course, there are also the benefits of less drag and psychological placebo effect.
[+] [-] cecilpl|11 years ago|reply
I found that combination to lower my times by about 1 second per 50m, or about 5%. I don't know how much of that is attributable to the shaving, but I will say it helped me "feel" way faster.
[+] [-] myleskeating|11 years ago|reply
http://www.reuters.com/article/2012/03/28/us-science-cancer-...
Summary: a team at Amgen discovers 47 of 53 "landmark" studies published in high-quality journals could not be reproduced. A team at Bayer did an internal review of programs they had initiated based on journal studies and found that less than a quarter of those findings could be reproduced.
Three very damning quotes: "Some authors [of the journal articles] required the Amgen scientists sign a confidentiality agreement barring them from disclosing data at odds with the original findings."
"'We went through the paper line by line, figure by figure,' said Begley. 'I explained that we re-did their experiment 50 times and never got their result. He said they'd done it six times and got this result once, but put it in the paper because it made the best story. It's very disillusioning.'"
"The problem goes beyond cancer. On Tuesday, a committee of the National Academy of Sciences heard testimony that the number of scientific papers that had to be retracted increased more than tenfold over the last decade; the number of journal articles published rose only 44 percent."
Academics are pressured to produce publications, not to produce science, and their studies are not always rigorous (not blinded to experimenters, etc.). People with high integrity and ability do produce good science that gets published, but unfortunately that appears to be the minority, even in highly prestigious journals.
So I'm curious: how would you fix it?
One thing the article mentions that might improve things is every journal dedicating one complete issue a year to reproducing the most influential studies of the year. Another could be getting a consortium of pharmas (who try to reproduce studies all the time, because if you're going to successfully make drugs you need the thing to work) to publish their internal data for the benefit of all. Does something like that exist?
[+] [-] jrapdx3|11 years ago|reply
Strictly my own imagination, but I'm anticipating the introduction down the road of the world's most advanced hair removal system that gives cyclists a big aerodynamic advantage proven by scientific tests. Yes buy the XYZ system and fly to victory! Wow, I really am jaded, but too many times we've seen it happen.
So much bad science obscures the good work because the latter doesn't make the news, it's far too boring to attract attention. It's the small incremental, tedious, repetitious, careful, persistent work that provides the real advances. Edison I think said, "we find 20,000 ways it doesn't work" and learn something every time we try.
I propose a simple set of remedies. Journals should give highest priority to publishing careful replications of prior studies, whether it's yes/no/maybe. Negative studies whether original or replications are give as much priority and those confirmatory. Novel associations are of course welcome if meeting standards of adequate power to discern something beyond quirky results.
Ultimately, the impact of hyperbolic claims about the meaning of research causes the greatest distortions of scientific process and progress. Journal editors can solve the great bulk of misinformation their journals promulgate. It's remarkably simple. All they have to do is issue an edict, all that authors can write about are the history, background, what they did and factual results of their work. These "rules" apply to observational and experimental work all the same. IOW it would be forbidden to draw conclusions about the what the outcomes mean, what is proven, or what "causes" what.
Sure giving context about past results is necessary and usefully informative, but conclusions are for we the readers to determine. If this was the case, suddenly the strident "answers" and premature incorporation of findings into practice will be sharply reduced. Hysteria will subside. We can then actually use our scientific talent to accomplish honest goals, and solve the real and daunting problems we actually have.
Perhaps this seems a radical view and maybe it is. It's not whether I'm right or anybody will make any of these substantial changes. It is about getting back to careful thoughtful scientific inquiry and reducing misdirected human energies.
[+] [-] ck2|11 years ago|reply
I wouldn't have figured it to be so much but this doesn't seem so incredible to me.
Similar thing for swimming.
[+] [-] ccozan|11 years ago|reply
[+] [-] beseku|11 years ago|reply
I always thought it was an urban myth that it made you go faster, and that the real reason was that road rash was easier to treat.
[+] [-] jamessb|11 years ago|reply
[+] [-] graemian|11 years ago|reply
[+] [-] pdxandi|11 years ago|reply
[+] [-] IvyMike|11 years ago|reply
[+] [-] MatmaRex|11 years ago|reply
[+] [-] vhost-|11 years ago|reply
[+] [-] nodata|11 years ago|reply
[+] [-] rasz_pl|11 years ago|reply
[+] [-] Too|11 years ago|reply
[+] [-] anvarik|11 years ago|reply
[+] [-] shiven|11 years ago|reply
[+] [-] mosselman|11 years ago|reply
[+] [-] eru|11 years ago|reply
[+] [-] bildung|11 years ago|reply
[1] If you design a study you can actually start from the other end: If you can estimate the size of the effect to be measured, you can calculate the number of people needed for significance beforehand.
[+] [-] bch|11 years ago|reply
(Edited to describe my experience, per "let's not read the article" comment).
[+] [-] mosselman|11 years ago|reply