Olympic advantage: 'You have to know the flow'
In the world of swimming, milliseconds can mean the difference
between gold and last place in a race in the Olympics. That is where
technology comes into play.
Experimental flow measurement techniques are helping American
swimmers sharpen their strokes, shaving seconds from their lap times in
Beijing.
Professor Timothy Wei, head of Rensselaer Polytechnic Institute in
Troy, N.Y.’s Department of Mechanical, Aerospace, and Nuclear
Engineering and acting dean of the university’s School of Engineering,
helped develop top-secret, state-of-the-art equipment and mathematical
techniques that USA Swimming coaches have been using to help train
Olympians.
A single frame from a research video illustrating the flow of
water around former gold medalist and current Olympian Megan Jendrick. |
“This is the real thing,” Wei said. “We have the physical system,
we’re taking flow measurements of actual swimmers, and we’re getting
more information than anyone has ever had before about swimming and how
the swimmer interacts with the water. And so far, these techniques have
contributed to some very significant improvements in the lap times of
Olympic swimmers.”
In years past, swimming coaches have used computer modeling and
simulation to hone the techniques of athletes. But Wei developed
state-of-the-art water flow diagnostic technologies, modifying and
combining force measurement tools developed for aerospace research with
a video-based flow measurement technique known as Digital Particle
Image Velocimetry in order to create a robust training tool that
reports the performance of a swimmer in real time.
“This project moved the swimming world beyond the observational into
scientific fact,” said USA Swimming Coach Sean Hutchison. “The
knowledge gained gave me the foundation for which every technical
stroke change in preparation for the Beijing Olympics was based.” (For
videos that explain the process, visit http://www.rpi.edu/news/video/wei/videos.html.)
The secret, Wei said, is in understanding how the water moves. The
new system incorporates highly sophisticated mathematics with
stop-motion video technology to identify key vortices, pinpoint the
movement of the water, and compute how much energy the swimmer exerts.
“You have to know the flow,” Wei said. “To see how a swimmer’s
motion affects the flow, you need to know how much force the swimmer is
producing, and how that force impacts the water.”
“Swimming research has strived to understand water flow around a
swimmer for decades because how a swimmer’s body moves the surrounding
water is everything,” said USA Swimming’s Biomechanics Manager Russell
Mark. “The ability to measure flow and forces in a natural and
unimpeded environment hasn’t been available until recently, and Dr.
Wei’s technology and methods presented USA Swimming with a unique
opportunity that United States swimmers and coaches could learn a lot
from.”
Wei has been working with USA Swimming for several years, but the
idea and design of the new flow measurement tool really took shape in
2007. Most of the preliminary tests occurred in October 2007, and the
coaches and swimmers have spent the past several months incorporating
what they have learned into their training regimes. For any swimmer, it
takes time to make adjustments to their strokes and practice new
techniques, Wei said.
One highlight of working on the project was when Mark arranged for
Wei to attend the 2007 and 2008 U.S. Summer Nationals and be on deck
with the swimmers.
“How often does a researcher get to do something like this?” said
Wei, whose young son and daughter also swim competitively. “It’s been a
journey into a world that someone like me would have never before
gotten the privilege to see first-hand.”
he is human with gills ehehe m' feeling sorry for other swimmers its their badluck to be there in an era of phelps.n' am sure abt eight re kya
