
The curious case of the cyclist’s unshaven legs - soundsop
http://www.theglobeandmail.com/life/health-and-fitness/health/the-curious-case-of-the-cyclists-unshaved-legs/article20370814/
======
sjackso
> 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.

~~~
epistasis
I've never encountered a field in science where fundamental results aren't
sufficiently replicated by other labs.

That _nobody_ spent $500-$2000 to estimate leg hair drag probably speaks more
about people not wanting to be caught measuring leg hair drag than about the
entire field's tendency to replicate findings. It's also really weird for
people to consider $500/hour tunnel time to be expensive for a sport with as
much money as cycling.

Really, I thought it was weird, and probably inappropriate, to mix in so much
of an outsider's amateur and unsopported _opinion_ about science into an
otherwise interesting story about leg hair drag.

If there's a serious story somewhere about results not getting replicated when
they should in many fields of science, I'd like to hear about it. There's
often stuff on the fringe, but any serious result will be replicated soon.
Take, for example, the acid-bath stem cell retraction from not long ago. Where
else are important results not replicated? The Higgs? It's a baffling
perspective.

~~~
thaumaturgy
> _If there 's a serious story somewhere about results not getting replicated
> when they should in many fields of science, I'd like to hear about it._

Actually, there is! It's been referred to as "the decline effect", and it's
fascinating.

The New Yorker published an article about it a few years ago
([http://www.newyorker.com/magazine/2010/12/13/the-truth-
wears...](http://www.newyorker.com/magazine/2010/12/13/the-truth-wears-
off?currentPage=all)). It has resurfaced in popularity a couple of times. It
was written by disgraced journalist Jonah Lehrer, but later independent
investigation failed to find any fault with the article he wrote
([http://www.lastwordonnothing.com/2012/11/05/jonah-lehrer-
nat...](http://www.lastwordonnothing.com/2012/11/05/jonah-lehrer-nature-of-
truth/) \-- worth reading because it includes statements from scientists on
Lehrer's article).

So far, my favorite explanation is the direct, obvious one, which is that
we're sometimes -- perhaps more often than we'd expect -- falling victim to
statistics. Given the very large number of experiments and studies being
conducted everywhere, and the selection for positive results, statistical
anomalies are being accidentally selected for and then not being extensively
enough re-evaluated much later.

The article discusses that as a possible explanation, but the journalist does
his job, igniting reader interest, by suggesting the effect somehow "defies
the laws of statistics". I favor the simpler explanation, which is that our
meat brains simply underestimate the vast number of ways in which statistics
would like to bugger us.

Some of the things that both you and the parent commenter mention are
discussed in the article. For example:

> _Jennions, similarly, argues that the decline effect is largely a product of
> publication bias, or the tendency of scientists and scientific journals to
> prefer positive data over null results, which is what happens when no effect
> is found._

and

> _Richard Palmer, a biologist at the University of Alberta, who has studied
> the problems surrounding fluctuating asymmetry, suspects that an equally
> significant issue is the selective reporting of results—the data that
> scientists choose to document in the first place._

(aside: I'm not one of HN's vocal "science is junk" members. I love science,
or, at least, I like to admire its butt
([http://explosm.net/comics/3557/](http://explosm.net/comics/3557/)). I don't
believe there's something fundamentally wrong with the scientific method. But,
I do think more emphasis needs to be placed on repeatability of experimental
results over longer periods of time, and I hope that this will become more of
a trend as the world economy continues to grow.)

~~~
epistasis
This is very fascinating stuff! And it's also familiar from GWAS where there's
a fantastic number of statistical tests.

However, it's all examples of things being replicated in the sense of (1)
being tested again, and being "not replicated" in the sense of (2) being
tested again and being found to not repeat as initial reports.

I think the article's complaint was about (1), though I find this (2) far more
interesting and will pursue these threads, thanks!

------
nl
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.

[1]
[https://www.youtube.com/watch?v=DZnrE17Jg3I](https://www.youtube.com/watch?v=DZnrE17Jg3I)

[2] [http://www.amazon.com/Faster-Obsession-Science-Fastest-
Cycli...](http://www.amazon.com/Faster-Obsession-Science-Fastest-
Cyclists/dp/1408843757)

~~~
Shivetya
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.

~~~
chrisbennet
Yes, it was "already established" that hair caused drag.

That is why this study was so surprising. They found that hair _decreased
drag_.

~~~
seren
> The tests showed that shaving his legs reduced Thomas’s drag by about 7 per
> cent, allowing him to exert 15 watts less power and still go at the same
> speed. In theory, that translates to a 79-second advantage over a
> 40-kilometre time trial that takes about one hour.

Shaving reduces the drag, but the originally study measured the reduction
around 0.6 percent while this one found a 7 percent reduction. So, about 10
times bigger than anticipated.

~~~
chrisbennet
Oh you're right!!

When I read this "Even more confounding was that the results _contradicted_
earlier findings" it totally colored my reading of the article. (Emphasis
mine.)

------
jmadsen
Strange. When I was racing, we never thought about drag, except as a joke.

We shave because it helps reduce road rash when you go down on asphalt (slide
easier) & easier to keep the wounds clean afterwards.

~~~
AndrewKemendo
Exactly right. I raced in college and it was well known that shaving was for
making it easier to deal with injuries/massage.

A bit of it is also in-group/out-group signaling.

------
nether
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.

------
jpatokal
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.

~~~
UnoriginalGuy
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.

------
serf
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.

------
idlewords
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.

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](https://www.youtube.com/watch?v=DZnrE17Jg3I)

------
andyjsong
Interesting, I wonder how dramatic the effect is with swimming, there are swim
flumes like this
[https://www.youtube.com/watch?v=feUhyCklHL0](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.

~~~
shiloa
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.

------
myleskeating
Relevant article on similar lack of reproducibility in cancer research.

[http://www.reuters.com/article/2012/03/28/us-science-
cancer-...](http://www.reuters.com/article/2012/03/28/us-science-cancer-
idUSBRE82R12P20120328)

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
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.

------
ck2
After 15mph a great deal of energy is used to overcome wind resistance.

I wouldn't have figured it to be so much but this doesn't seem so incredible
to me.

Similar thing for swimming.

------
ccozan
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.

~~~
beseku
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.

~~~
kevin_thibedeau
I am not a competitive cyclist but remove the hair on my legs with a depilator
in the Spring because my leg pelt retains too much heat in the Summer. There
is a noticeable improvement in cooling after it is done.

While not the most pleasant process, it avoids stubble and the delayed
regrowth means the new hair is sufficiently long to begin providing warmth
just in time for when cooler Fall temps arrive. I always considered that to be
the real reason why the pros do it with road rash being of secondary concern.
Those with shorter leg hair just went along and copied their hairier peers.

------
jamessb
Specialized previously investigated the effect of shaving off a beard, and
found that it had a negligible effect:
[http://www.bikeradar.com/us/road/news/article/specialized-
te...](http://www.bikeradar.com/us/road/news/article/specialized-test-
aerodynamics-of-a-beard-video-41144/)

------
graemian
If a cyclist invested the weekly time he spent shaving his legs in extra
training instead, would he be better off?

~~~
pdxandi
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.

------
IvyMike
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.

~~~
MatmaRex
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".

------
vhost-
Does anyone know why wind tunnel use costs $500 an hour? Electricity bill?

~~~
rasz_pl
Setup costs.

~~~
jtheory
That's my guess -- they must be quite expensive to build, with quite a bit of
specialized hardware involved (not exactly off-the-shelf stuff!), and highly-
specialized people to run it ...but then only one experiment can use the whole
shebang at a time (including setup/teardown time), so they can't spread out
the costs across lots of concurrent users.

------
anvarik
Reminds me Hitchhiker's Guide to Galaxy, and those planet creators

------
shiven
Compared to numbers from earlier studies (0.6), the new number (7) looks
suspiciously like a floating point error arising from software/hardware
issues!

------
mosselman
A good thing that 5-6 people is a statistically significant number of
participants....

~~~
eru
It can be, if the effect is big enough compared to noise. (In medicine you
usually have much more noise, that's why you need more participants.)

~~~
mosselman
I appreciate that in medicine it can be. But this is not medicine. In this
case the 'research' was obviously done by first letting someone cycle WITH
hair, then they were shaved (with time to recover I imagine) and then they
tried again. I say 'obviously' because this little participants is not enough
because you'd need more people to be able to compare means in performance
differences.

The problem I see however is that after being shaved the participant would
feel faster and thus behave faster. A sort of placebo effect if you will. At
the same time, the cyclist-cultural effect of being 'unshaved' in the first
test would make them feel sluggish. The same effect as seen in experiments
where participants are presented with negative messages vs positive messages
and asked to perform tasks. The participants exposed to negative messages, as
expected, perform poorly in comparison to the other group.

In conclusion, I feel, that this 'research' can only be used as something to
base you hypothesis on, but it is in no way conclusive in its current setup.
You'd need to have random groups of cyclists, some of whom are, to begin with,
shaved, and some who are not. It would maybe be easier not to use cyclists in
order to find a diverse enough set of participants. Then again I don't know
how many regular cyclists go around unshaven.

~~~
dllthomas
This wasn't "how fast can you get from A to B" \- they were cycling at a
steady rate on a stationary bike in a wind tunnel. Pedalling faster would not
_trivially_ make the results better (it might have some complicated
aerodynamic effect, but I don't have any clue of the likely size or
direction).

~~~
mosselman
Yes you are right. The effect would be pretty trivial. I was wrong. Thats what
I get for trying to be a know it all. :)

~~~
eru
But that's how you learn on the internet. Asking questions gets you ignored,
you have to put up false claims to get corrected. :o)

------
bch
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).

~~~
mosselman
Yes, lets all not bother reading articles before commenting from now on.

