Anatomy is destiny for sprinters
Lance
Nov 12th 2009
From The Economist print edition
Sprinters are different from other people
IS ATHLETIC prowess attained or innate? Those who have suffered the
tongue-lashing of a tyrannical games master at school might be
forgiven for doubting the idea that anyone and everyone is capable of
great sporting achievement, if only they would put enough effort into
it. Practice may make perfect, but not all are built in ways that make
it worth bothering in the first place.
The latest evidence of this truth has been gathered by Sabrina Lee of
Simon Fraser University in Vancouver and Stephen Piazza at
Pennsylvania State University. They have looked at the anatomy of
sprinters and found that their feet are built differently from those
of couch potatoes.
Dr Lee and Dr Piazza already knew that sprinters tend to have a higher
proportion of fast-twitching muscle fibres in their legs than more
sedentary folk can muster. (These fibres, as their name suggests,
provide instant anaerobic pulling power, rather than the sustained,
oxygen-consuming effort that is needed by longer-distance runners.)
They suspected, though, that they would find differences in the bone
structure as well. And they did.
They looked at seven university sprinters who specialise in the 100-
metre dash and five 200-metre specialists, and compared them with 12
non-athletic university students of the same height. In particular,
they looked at the sizes of bones of the toes and heel. They also used
ultrasonic scanning to measure the sliding motion of the Achilles
tendons of their volunteers as their feet moved up and down. This
allowed them to study the length of the lever created by the tendon as
it pulls on the back of the heel to make the foot flex and push off
the ground.
Dr Lee and Dr Piazza found, as they report in the Journal of
Experimental Biology, that the toes of their sprinters averaged 8.2cm
in length, while those of non-sprinters averaged 7.3cm. The length of
the lever of bone that the Achilles tendon pulls on also differed,
being a quarter shorter in sprinters.
These findings suggest sprinters get better contact with the ground by
having longer toes. That makes sense, as it creates a firmer platform
to push against. In a sprint race, acceleration off the block is
everything. Cheetahs, the champion sprinters of the animal kingdom,
have non-retractable claws that give a similar advantage.
The reason for the difference in the Achilles tendons, though, is less
immediately obvious. At first sight, sprinters might be expected to
have more Achilles leverage than average, not less. First sight,
however, is wrong. When muscles have to contract a long way, they
usually do so quickly and with little force. When contracting short
distances, though, they move more slowly and generate more force.
Having a short Achilles lever allows the muscles that pull on the
tendon to generate as much as 40% more force than the same muscles in
a non-sprinter would be able to manage.
It is possible—just—that these anatomical differences are the result
of long and rigorous training. But it is unlikely. Far more probable
is that the old adage of coaches, that great sprinters are born not
made, is true. Everyone else, games masters included, should just get
used to the idea.
http://www.economist.com/sciencetechnology/displayStory.cfm?story_id=14843831
Dave Smith
I would think that innate potential is very important for most sports,
as well as for intellectual achievement, musical expertise and so
forth. Of course, training and practice are also required if the
potential is to be fully realised.
Dave Smith
Lance
True enough. Thanks for the reply.
Lance