U.S. Olympic swim team turns to technology to perfect strokes

November 2000: Aquatic Facility Design and Management  Credit: Allsport
COLORADO SPRINGS, Colo. In the competitive world of swimming, nothing is too extreme to consider in efforts to shave fractions of a second off a swimmer's finish time.

So it should come as no surprise that shaved bodies and full-body skinsuits have been joined by the latest computer technology.

Aided by advanced modeling and simulation software, USA Swimming is designing and helping its elite swimmers achieve their perfect swim stroke.

USA Swimming, headquartered in Colorado Springs, Colo., at the U.S. Olympic Training Center, is the national governing body for the sport of competitive swimming in the United States. Until recently, USA Swimming's research has been strictly experimental.

Last year, USA Swimming became aware of groundbreaking research that was being done to analyze a swimmer's strokes by Barry Bixler, principal engineer at Honeywell Engines and Systems, using computational fluid dynamics (CFD) software, which is used to analyze fluid flow.

What began as a hobby for Bixler has turned into extremely pertinent consulting research that is aiding USA Swimming to fine-tune the strokes of their elite swimmers.

Using software from industry leader Fluent Inc., Bixler began running computer simulations of a swimmer's hand and arm, altering certain variables, such as position of the hand and arm during a swim stroke and water turbulence. His preliminary CFD results compared well with traditional physical experimental data that had been arduously developed from a wind tunnel, a tow tank, and a flume.

"Not only will Barry's work allow us to analyze conditions, such as acceleration, deceleration and rotation of a swimmer's stroke, that we could not have done experimentally, it has also allowed us to gain valuable data much more quickly and cost effectively," said Scott Riewald, Biomechanics Director of USA Swimming.

After joining forces with USA Swimming, Bixler's research has progressed quickly. His first project on research of a swimmer's hand and arm is taking place in three phases.

In Phase I, which took place last year, the hand/arm was analyzed in steady flow. Bixler's main finding from this phase was that the aerodynamic efficiency of the hand is significantly less than an airfoil of similar aspect ratio.

Phase II, which has just been completed and was sponsored by the Sport Science and Technology division of the US Olympic Committee, analyzed the acceleration and deceleration of the hand/arm. Phase II results showed that drag and lift forces on the hand and arm are affected unequally by acceleration and deceleration.

Phase III, which is planned for next year, will analyze the addition of rotation and direction change of the arm, making it possible to "design" the optimum stroke. Full body analysis is also planned as a separate project to begin in the near future, in conjunction with Phase III of the hand/arm.

"Through this extensive research, I hope to demonstrate to the swimming community the benefits that can be achieved by gaining valuable information from such a simulation program," Bixler said. "CFD is a tool that is just too powerful and useful to ignore, and fortunately, USA Swimming has chosen to lead the way in applying it to swimming. Ultimately, I hope to 'design' the optimum stroke which will improve elite swimmers' performance."

According to Keith Hanna, director of marketing Communications at Fluent, "While Barry's research in the sport of swimming has never been done before, using this technology in sports engineering is not completely new.

Fluent's CFD software has been used by such recognized names in the world of sports as Team New Zealand to design the hull of their winning yacht in the 2000 America's Cup, by Benetton Formula 1 and Team Rahal in designing their racecars, and by Quicksilver (WRS) Ltd. in designing their craft which will challenge the world water speed record in the winter of 2001/2002.

CFD has also been used to analyze the trajectories of a soccer ball to determine optimum ball design and to analyze the benefits of "V" style ski jumping vs. parallel ski jumping, just to name a few. The use of CFD in sports to help gain a competitive edge, through improved personal techniques or through better equipment design, is burgeoning," Hanna concluded.

While Riewald and Bixler feel that it may be too early for Bixler's initial results from Phase I and II of the hand/arm analyses to affect the performance of the swimmers competing in the 2000 Olympics, both Riewald and Bixler are confident that this research will definitely have an impact on swimmers' techniques and performance in their quest for "gold" at the 2004 Olympics.

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