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Thursday, December 18, 2014
|Source: Dubai Gold & Jewellery Group|
Can what you wear make you swim faster?
These days, honest swimmers aren't trying to gain a lap on competitors, but to win by hundredths of a second. At the Beijing Olympics, Michael Phelps won the 100-metre butterfly by 0.01 seconds. Did his swimsuit help him?
If today's female Olympic swimmers were still weighed down by the swimming costumes of the 1890s, women would be "racing" in no less than stockings, bloomers and a short-sleeved dress.
Fast forward to the 1970s, when male swimmers wore spandex briefs the size of dinner napkins, following the idea that less material brought about faster times. Now, swimsuits are again approaching full-body coverage, this time trying to resurface the swimmer's body to be better than, well, the swimmer's body.
Manufacturers are changing materials and fits, as well as collaborating more closely with scientists who know fluid dynamics, to try to supply that precious hundredth of a second. Suits, now sounding like airplanes, are welded, computer-modeled and tested in wind tunnels. But when the finishes are so close, it's hard to say what brings about the difference: suit, skill, psychology or chance.
You can control the watery tumult sloshing between you and the finish line without a special swimsuit in a few ways. You can lower pressure drag by controlling how you present yourself to the water. It's really your vertical surfaces - that is, those perpendicular to your swimming - that push the water. If you dive in sleekly, keep your body in a horizontal line as you swim and don't allow your legs to sag, you've done a lot to reduce pressure drag. The water will push hard only on your head, shoulders, fingertips and feet.
Beyond that, get out the shaving kit. Shaving your body hair cuts drag by smoothing your surface. With less roughness, water will flow over you more easily. Of course, you can also hit the gym. Strong abdominal muscles will help you stay straighter and float higher in the water. With a strong upper body, you can worry less about drag - you'll compensate with more powerful strokes. But if your technique and your body are in top form and you still want to swim faster, then someone wants to sell you a swimsuit.
The concept of a "fast" suit relies on some assumptions. First, it assumes that your swimsuit can not only cover you without adding to your drag, but that it can reduce your drag. Second, it assumes that the drag-reducing features on your suit will help you swim more quickly, without making you use more energy or oxygen.
The international governing body for swimming, FINA (or Federation Internationale de Natation), approved the first full-body suits that claimed to reduce drag in time for the 2000 Olympic trials. Swimmers sported various body and leg suits at the 2000 and 2004 Olympics, culminating with Speedo's LZR Racer in 2008. Speedo claims that this is the fastest suit on the market.
The LZR Racer is smoother than hairy or shaven skin, one reason why Speedo says it's advantageous to squeeze into the suit rather than to swim in briefs. The smoothness comes from the materials; Speedo's woven spandex has a "flatter structure" than knitted material, and the panels, which were optimised in NASA wind tunnels.
It's not only the suit material that Speedo tried to smooth, but the swimmer. Swimmers aren't built like torpedoes, but like bumpy human beings. The curves of their frames and muscles add to pressure drag, which is even worse than friction on a rough suit. And in churned-up water, even the buffest swimmer's skin and muscles shimmy, adding to pressure drag. Speedo tried to "smooth a swimmer's lumps and bumps" by making the suit compressive.
For all its coverage and squeezing, the LZR Racer remains light. Speedo's spandex weighs 100 grams per square metre, four times less than standard swimsuit material. The spandex is also coated with a water-repellent substance, so it doesn't retain water, making it lighter. In simulated race conditions, swimmers swam a start, a 10-metre freestyle and a turn dressed in the LZR Racer and in normal training suits. They swam four per cent faster and used five per cent less oxygen in the LZR Racer. So presumably, they didn't swim faster because they worked harder. It was because of reduced drag.
Something strange happened with swimming records in 2008. A professor of kinesiology at Indiana University ran a statistical study on swimming world records since the 1970s. The number of world records broken has gently curved upward, and record times have gently curved downward, but both are reaching plateaus, as expected.
The year 2008 was a curve-cracking anomaly. More than 40 records were set in 2008, double the average for the last 30 years. The fastest men in the 100-metre freestyle at the Beijing Olympics swam, on average, almost four standard deviations faster than predictions.
Swimmers set significantly more records in February and March 2008 than during those months in the past 30 years. Speedo introduced the LZR Racer in February 2008. The statistics weren't out of the ordinary in previous years, when other fast suits were introduced.
Coaches are better. There's more video feedback. But the suit is really the only thing that has changed. The same professor of kinesiology pulled a case study from Japan. In April 2008, at the Japan Olympic trials, no swimmers wore LZR Racers. Two months later, at the Japan Open, swimmers competed in LZR Racers in the same pool. Swimmers swam significantly faster at the Open, although they were presumably trying for faster times at the trials. Strangely, sprinters improved significantly more than distance swimmers.
Data like these support - but far from prove - that the LZR Racer makes swimmers faster. But the data focus on swimmers who are already fast.
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