Faster designs and deeper analysis advance the high-tech sport of swimming.
by Harry Hutchinson, Executive Editor
To the untrained eye, few activities seem to be as low-tech as swimming—just you and your buoyancy out there communing with the whales. You do it barefoot. How primitive is that?
As we know, though, swimming ranks among world-class sports, where technology, technique, and conditioning rule.
The high-tech nature of swimming was clearly apparent in two recent events. Speedo, which prides itself on pushing the envelope that swimmers wear in the water, unveiled what it calls its fastest swimsuit so far. The design is based on research using 400 body scans of athletes, a NASA wind tunnel, Fluent CFD software, and a water flume at Otago University in New Zealand.
A day or so after Speedo showed the suit at a gathering in New York, a British organization, the Engineering and Physical Sciences Research Council, issued a press release describing work it is funding to develop software that will analyze a swimmer's performance in real time.
 Gold standard: Olympic medalist Michael Phelps demonstrates Speedo's new LZR Racer suit.
Both developments, it seems, address drag that affects a swimmer gliding through the water in a rigid streamlined position, as after a dive or a turn. According to Speedo, a competitor in a 50-meter race may hold a streamlined position for as many as 15 meters.
Speedo's new suit, which the company calls the LZR Racer, was developed by the company's research unit, Aqualab, with the aid of athletes, coaches, scientists, and engineers.
According to Speedo, the LZR (pronounced "laser") Racer reduces passive drag on a swimmer by about 10 percent below that of the Fastskin FSII, a suit introduced in 2004. Speedo says the FSII was worn by 53 percent of the gold medal winners in the Olympic Games that summer. An article, "Swim Like the Sharks," in the May 2004 issue discussed the development of the FSII suit. The suit made use of a material that Speedo had developed to simulate a shark's skin, particularly the small surface projections called denticles that help manage the flow of water. It also was contoured to control drag and for ease of movement.
Speedo introduced a suit last year made of a new material called LZR Pulse, which was even faster. It is a water-repellent combination of elastane yarn and ultrafine nylon thread. More than 20 world records have been broken by swimmers wearing that suit, Speedo says.
 Swim to win: Ross Sanders (left) of the University of Edinburgh and Roozbeh Naemi are developing a computerized system to aid British swimmers.
According to the company, the LZR Racer experiences about 5 percent less drag than last year's suit. The LZR Racer consists of three pieces of fabric, bonded rather than stitched for a smoother surface. Speedo says it has applied for 16 patents worldwide in connection with the suit.
Dave Pease, a sports scientist, studied several world-class swimmers and manikins in a water flume at Otago University's Human Performance Center, to assess passive drag on various suits at different velocities. The water moved while swimmers remained streamlined during the tests.
The wind tunnel tests for Speedo were conducted at the Langley Research Center in Hampton, Va. According to Steve Wilkinson, an aerospace engineer at Langley's Fluid Physics and Control Branch, "We evaluated the surface roughness effects of nearly 60 fabrics or patterns in our small low-speed tunnel, which is perfect for this purpose. We were assessing which fabrics and weaves had the lowest drag."
CFD software calculated friction, pressure, and fluid flow around swimmers to optimize the design to reduce drag.
Keith Hanna, corporate director of marketing in Europe for Ansys, said his company helped Speedo in the refinement of computer models using the company's Fluent CFD software.
"This is a simulation demanding high levels of fidelity, because the changes in hydrodynamics associated with each individual modification to the suit design and construction can be very small and subtle," he said. "Our many years of Formula 1 and America's Cup CFD experience has been applied to Speedo's applications."
According to Speedo, it also called on CFD advisers at the University of Nottingham in England.
 Fluid dynamic: CFD modeling guided designers of the LZR Racer to optimize the drag reduction of the new swimsuit.
LZR Pulse fabric is applied to particularly drag-prone parts of the body, which were identified by CFD analysis, Speedo said. The company said it did 400 body scans of competitive swimmers that guided the development of the pattern and construction of the new suit.
Speedo's competition suits will go on sale in May at retail prices between $290 and $550. A clothing design company, Comme des Garçons in Tokyo, will introduce suits under its label based on Speedo's design.
The EPSRC, meanwhile, says it is putting more than £110,000 into a year-long project to develop software that will give swimmers detailed analysis of their glide technique, the passive posture after dives and turns.
A swimmer will be marked at the body joints and photographed in action by video cameras. The software, when it is complete, will analyze the images so that data on head position, body posture, and the like will be available immediately for reference by swimmers and coaches during a training session. The software will be able to suggest ways to improve posture and when to start kicking.
 Into the wind: Steve Wilkinson tests a Speedo fabric sample in the 7x11-inch low-speed tunnel at NASA's Langley Research Center.
The software is being developed by researchers at the University of Edinburgh's Centre for Aquatics Research and Education with contributions by Sheffield Hallam University, in collaboration with UK Sport, a government body. Ross Sanders, a professor at the University of Edinburgh, is leading the project.
The software uses a mathematical model developed and published by Roozbeh Naemi, as part of his Ph.D. work completed at the University of Edinburgh in 2006.
The 12-month research project, formally known as "Improving Swim Performance by Optimising Glide Efficiency and Time of Initiating Post-Glide Actions" is due to end this June. The idea for the project arose from a series of workshops called "Going for Gold," sponsored jointly by EPSRC and UK Sport in 2006. The purpose of the workshops was to recruit British academic researchers to study questions identified by representatives of leading British sports.
UK Sport was established by Royal Charter in 1997 to advance the performance of British national sports teams. The Engineering and Physical Sciences Research Council is the U.K.'s main agency for funding research in engineering and the physical sciences. The EPSRC invests approximately £740 million a year in research and postgraduate training in various technological disciplines.
Sanders and the research team are focusing on the glide phase of swimming because it has been studied less than other critical parts of a swimmer's performance, such as the dive, the tumble turn, and the swimming stroke. The team may develop software in the future that could be applied to these other phases.
Once tested and validated, the glide-analysis system may be available to swimmers in the U.K. in about 12 months. | 
