
Arm-swinging riddle is answered - epi0Bauqu
http://news.yahoo.com/s/afp/sciencearmsoffbeat
======
jpwagner
The only problem I have with this experiment is that there is no control for
muscle memory.

If you compared the metabolic rate of a piano player playing piano vs. someone
who's never touched one before, intuitively the skilled player would
outperform the unskilled player. (There are certainly better examples.)

How much experience arm-swinging did those in the arm-swinging group have?

How much experience opposite-swinging did those in the opposite-swinging group
have?

How much experience keeping their arms still while walking did those in the
still-armed group have?

~~~
dbz
And is there a certain amount of swing that is most efficient?

~~~
jpwagner
I think you misunderstand.

Imagine I wanted to see which arm is better for throwing a ball: right or
left.

I choose 1000 subjects and ask 500 of them to throw lefty and 500 to throw
righty.

Do you see the issue with this experimental method?

------
RiderOfGiraffes
I've always claimed that the arm-swing counters the angular momentum of the
legs. Without that you have to expend more energy to prevent your body from
twisting. If you walk with your arms constrained that seems to require a
"twist" effect from somewhere else.

This could be complete nonsense, of course, but my personal experiments
suggest and support it.

~~~
huhtenberg
> _But a trio of specialists from the United States and the Netherlands have
> put the question to rigorous tests._

This trio clearly did not take Physics 101 at their specialist training
location. What you described is a conventional explanation for the arm
swinging as I heard it back in high-school over 20 years ago.

------
jerf
In a post a couple of weeks ago on HN, I commented on the difficulty of
redesigning the human body. In many contexts, people often suggest "obvious"
improvements to the human body, the classic being "let's just get rid of the
appendix". But I've get to see a redesign that I can guarantee is actually a
good idea.

Here's another example, where some people considered it "common sense" that
we'd be better off not swinging our arms around, but, when actually
_investigated_ , it turns out that what the human body is actually doing is
done for a reason (in the sense that not doing it is less optimal for the
body, not in the "intention" sense), and those who thought there was a trivial
improvement were wrong.

Just something I thought I'd point out, since this is such a perfect example.

~~~
Periodic
The appendix a popular target just because people aren't entirely sure what it
is there for, or weren't for a long time. In recent years we have found more
evidence that it has a function in the immune system and in the health and
homeostasis of the intestine.

Of course, the relative health of people who have had their appendix removed
reinforces this, but the same could be said of a few teeth and kidneys.

We really know very little about the actual purpose and processes of the body.
It's an incredibly complex machine. In fact, it is so complex that we
currently lack the ability to intelligently design a better one.

------
kqr2
How much arm-swinging do speed / race walkers do? Since they compete over long
distances and durations, saving energy would be a competitive advantage.

------
jemka
Arm Swing Challenged [http://www.funnyassblog.com/random-funny/arm-swing-
challenge...](http://www.funnyassblog.com/random-funny/arm-swing-challenged/)

------
jodrellblank
_The study, headed by Steven Collins at the University of Michigan at Ann
Arbor, says we should give the thumb's-up to arm swinging._

In our easy-calorie society, shouldn't we now give the _thumbs-down_ to arm
swinging? (And start telling people _to_ run in corridors)

------
joe_the_user
I learned this from my body work and martial arts studies. Good to have
scientific validation...

