After Michael Phelps blitzed his way to a record eight gold medals in Beijing, analysts likened him to a fish. The analogy should surface in London too, whether it's Phelps or his rival, Ryan Lochte, who rules the pool.
The calculation is pretty simple: The two American stars spend more time underwater, and swimmers go faster underwater.
The best example of the importance of underwater swimming may be the 200-metre backstroke, a punishing middle-distance race for which Lochte holds the Olympic record. By the third and final turn, most swimmers' bodies are so oxygen starved that they pop to the surface before the maximum allowed distance of 15 metres.
Lochte has made the third wall his signature. That's where he explodes off the wall and uses his superlative dolphin kicks to go the full 15 metres in about six seconds, usually popping up ahead of the pack if he wasn't there already. At the U.S. Olympic trials last month, the third wall is where he caught Tyler Clary, who had been leading at the first two turns.
So why doesn't everyone go the full 15 metres under the surface on every 50-metre lap?
It "hurts like hell," says Allan Wrigley, biomechanist with the Canadian Olympic swim team. When there isn't enough oxygen to fuel hard-working muscles, pain-inducing lactic acid floods the muscles. Holding your breath underwater and swimming full-throttle is a recipe for extreme discomfort.
But for a guy like Lochte?
"He's just that fit," Wrigley says. "He's that strong. He's that guy that, when he's on the third turn and it hurts like hell, he's just like, well, all my work hurts like hell."
If there's a place in the race where most swimmers can improve their times, it's by finessing their underwater technique, Wrigley says.
Which is why coach Don Burton and his London 2012-bound swimmer, Andrew Ford, showed up at the University of Florida last May. The duo, who train at the University of Guelph, were invited to train for a week with Lochte and Greg Troy, coach of the Florida Gators and the U.S. men's Olympic swim team.
It became clear that underwater swimming was an integral part of their daily regimen.
"They absolutely, 100 per cent, work that to death," Burton says.
On almost every lap, for almost every drill, Lochte did the full 15 metres underwater after his kickoff, to mimic a race. But he went farther, sometimes 25 or 35 metres, all to train his body and lungs to work in oxygen debt. In one particularly sadistic exercise, Burton says Lochte did a full 50-metre lap underwater, turned, did another 15 metres, and finally popped up and raced to the wall.
Another significant part of Lochte's training is dry-land weight work. YouTube is full of clips of Lochte flipping tractor tires, heaving beer kegs and whipping heavy ropes. Lochte's strength coach at Florida, Matt Delancey, recently told Sports Illustrated that Lochte also does more traditional power circuits that include squats and Olympic lifts like jerks, and cleans and snatches. Those exercises are designed to make him a better jumper because jumping is correlated to better starts, better walls and a great, streamlined dolphin kick.
There are also technical ways to improve, Wrigley says. The fastest moment in any race is when the swimmer pushes off the wall, he says. Swimmers go faster underwater because they are more streamlined beneath the surface. Turbulence at the surface increases drag and slows swimmers down. It's all about minimizing your loss of speed.
The best way to do that is to swim like a dolphin.
The dolphin kick creates less drag than a flutter kick, which is why swimmers use it underwater. The goal is to achieve the perfect undulating wave, with the lower half of the body cracking like a whip while the top half from the rib cage and above remains relatively still. Swimmers control the frequency of the wave and the amplitude, or height. Size is important; if it's too big, you create drag.
To do this well requires flexibility in the hips, knees, ankles. This can be improved with massage, stretching, yoga and more stretching. But genetic gifts can help. Phelps, for example, has size 14 feet and flexible ankles. Researchers specializing in fluid mechanics at George Washington University have found that this is ideal for maximum thrust.
Swimmers analyze their dolphin-kick technique with biomechanists such as Wrigley, tweaking their techniques to fit the demands of their own particular race and body type. Phelps, for example, has a bigger and slower kick than most swimmers, but that works for his long body. Other swimmers kick quickly, such as Australian backstroke specialist Meagen Nay, whose kicking style Wrigley compared to a hummingbird's.
Ford, 22, who will be competing in his first Olympics, in the 200-metre intermediate medley, says a perfect dolphin kick is great, but it's pain tolerance that puts Phelps and Lochte in a league of their own.
"They've found a way to train themselves or convince themselves to let their mind be in control instead of their bodies getting the best of their minds," Ford says. "It's really hard to do, but yeah, I'm trying."
This is the final part in a 10-part series on the science behind athletes' preparation for the London 2012 Summer Games.