# [ExI] NYT: Born to Run? Little Ones Get Test for Sports Gene

spike spike66 at att.net
Mon Dec 1 06:08:13 UTC 2008

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> ...On Behalf Of PJ Manney
> Subject: [ExI] NYT: Born to Run? Little Ones Get Test for Sports Gene
>
> ...Reminds me of a
> LA Clippers vs. LA Lakers game I attended 8 years ago.  Earl
> Boykins was playing guard with the LA Clippers and he blew my
> mind -- at 5'5" (165 cm), he was the greatest bundle of
> energy and speed on the court...

Mechanical engineers among us will get this one.  The short guys sometimes
play basketball like a bat outta hell.  They can be lightning quick compared
to the bigger guys because of a scaling law.  If one imagines scaling up a
human keeping all proportions constant, one sees that as the height
increases linearly, the cross section area of the muscles (thus the
strength) would increase as the square, the mass increases as the cube and
the moment of inertia of the limbs increases as the fifth power.

If we imagine a nominal human, then with all proportions constant, double
her height.  Her theoretical strength increases by four, her mass by eight,
and the moment of inertia (and thus the force required to produce any given
angular acceleration) is increased by a factor of 32.  Consequently, in
sports we see some interesting characteristics:

-the short basketball players are quick as lightning,
-the best gymnasts are always tiny and nimble,
-featherweight boxers are so fast it is difficult to score the
matches.

On this last point, if you get a chance to watch olympic style boxing, the
little guys are always the most interesting and difficult to count the
number of blows.  They seldom have enough strength and power to score
knockouts, so the decision is from counting blows.  There are plenty of
split decisions in the feathers, and the judges have way different scores
from each other.  Consequently, they intentionally slow down the feathers a
bit by making them use the same weight gloves as the heavies.

If you have ever seen two small guys mix it up bare fisted, especially if
they are sober, you will see some real speed.

spike

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