Since I can’t log in - can you summarize for us all?
I’m not sure if this is the whole thing, but I “borrowed” this from here:
http://forum.lowcarber.org/showthread.php?t=212438
Related to the thread on motor patterns and learning, swimming
stroke goes full circle: from I-pull to S-pull, back to
I-pull. So, if you have changed your pull (like I did in the
early '80’s) from I- to S-pull, you can change it back again!
ENGINEERING OF SPORT MEETING: Pulling Straight to the End of
the Pool Adrian Cho
DAVIS, CALIFORNIA–From 13 to 16 September, researchers from
many disciplines discussed sports from curling to skydiving,
from table tennis to boxing, at the 5th International
Conference on Engineering of Sport. For decades, competitive
freestyle swimmers have been taught to make an S-shaped path
when pulling their hands through the water. But measurements
and calculations now show that to generate the maximum thrust,
swimmers should pull their hands straight back through the
water, reports a mechanical engineer whose research was
inspired by his previous study of turtles. Swimmers have been
purposely doing the “S-pull” since the early 1970s, when famed
swimming coach James (“Doc”) Counsilman used underwater
cameras to film elite swimmers and found that they were moving
their hand first out to the side and then back under their
bodies. By moving side to side, hands acted like little
airplane wings or propeller blades, Counsilman argued,
generating hydrodynamic lift that pulled the swimmer through
the water. That lift would supplement the force generated by
simply pushing against the water with the palms. In recent
years, researchers have questioned just how large and
important the lift forces are, but the S-pull has remained a
standard technique among competitive swimmers.
However, the S-pull may not be the best pull for all races and
circumstances, says Shinichiro Ito of Japan’s National Defense
Academy in Yokosuka. Using measurements of the lift and drag
coefficients of manikin hands and a computer model of a
swimmer, he found that the S-pull makes the most efficient use
of energy, as it maximizes the ratio of lift to drag. It does
not, however, generate the most thrust. Instead, Ito found, a
straight “I-pull” yields more pure power.
Thorpedo away! Olympic champion Ian Thorpe pulls his hands
straight through the water. [the image is missing here, but
not the one in my head -Thorpe rules!]
Ito had already observed something similar in his study of
freshwater turtles. When paddling about leisurely, turtles
wave their feet in flourishes, doing a reptilian version of
the S-pull. When frightened, however, terrified terrapins pull
their feet straight back to swim away as fast as possible.
Analysis showed that for turtles, the sinuous movement was
more efficient, Ito says, but the straight movement produced
greater thrust. Other familiar creatures also provide living
examples of the advantages of the I-pull. Underwater video
shows that Australian swimming sensation Ian Thorpe snaps his
elbow and pulls his hand straight through the water, Ito says.
Other swimmers are following the nine-time Olympic medalist’s
lead, says Yuji Ohgi, a professor of physical education at
Keio University in Fujisawa, Japan. “At the Sydney Olympics
, only Ian Thorpe had the I-shaped pull,” he says.
But now, “many, many Australian swimmers do it.”
Switching from S-pull to I-pull isn’t easy, says Ohgi, who is
also a swimmer. Good swimmers generate power by rolling from
one side of their bodies to the other, he says, and that makes
their hands move side to side almost automatically. “The
I-shaped pull is rather more difficult than the S-shaped pull
because of the rolling motion” of the body, Ohgi says. Still,
to shave every fraction of a second from their times, more
swimmers are tackling the challenging technique and learning
to swim like a frightened turtle.
From this week’s issue of Science.
Well, the S-shaped pull might still be the way to go in long distance swimming for triathletes, who have to find a compromise between pure power (I-pull) and economy (S-pull).
I agree that for most swimming events, with all the weight-training and muscle built-up in swimmers, the I-pull might be the way to go for most distances.