A Revolution That Began With a Kick

Michael Phelps, center, here at the start of the 200-meter butterfly semifinal at the 2004 Olympic Games in Athens, has mastered the dolphin kick. (By Donald Miralle -- Getty Images)

Phelps's turns and underwater kicking were the difference, Bowman said. "Free-swimming 200 straight meters, Ian would probably win handily."

Also known as the fly kick because of its connection with the butterfly stroke, the underwater dolphin kick has become so important, some coaches contend, it has earned its own classification.

"There are now five strokes," Schubert said. "The fifth stroke is the underwater dolphin kick."

Origins of the Kick

The underwater dolphin kick attracted the interest of swimming innovators as early as the 1930s. The late Volney C. Wilson explored its possibilities before diving into later work on nuclear fission and the atomic bomb, according to David Schrader, a research professor at Marquette University who is Wilson's biographer.

Schrader said Wilson, an alternate on the 1932 Olympic water polo team who studied fish propulsion at a Chicago aquarium, claimed to have shown the kick to Johnny Weissmuller, a training mate at the Illinois Athletic Club.

"Weissmuller reproduced it perfectly, but was not impressed by it," said Schrader in a phone interview, recalling a conversation with Wilson.

Indeed, the kick did not immediately take off. For years, swimmers relied on the flutter kick in the freestyle. The dolphin kick has always been associated with the butterfly, which was not contested in the Olympics until 1956.

One of the first swimmers to turn heads with the underwater dolphin kick was David Berkoff, a Harvard graduate who became known for the "Berkoff Blastoff." In 1988, Berkoff set several world records in the 100 backstroke by dolphin-kicking for 35 meters underwater at the start of the race. When rivals began doing the same, FINA, the sport's international governing body, acted quickly, banning underwater swimming in the backstroke for more than 10 meters, then later, 15 meters.

Seven years later, Arizona-based swim coach Bob Gillet urged his young butterfly star, Misty Hyman, not only to do the dolphin kick underwater as long as she could, but also to swim on her side to enhance the stroke's effects. By 1997, she was winning butterfly races by swimming 35 meters underwater.

A year later, FINA banned swimming underwater more than 15 meters for the butterfly and freestyle. (In the breaststroke, swimming underwater has been banned since the 1950s; however, since 2005, competitors have been allowed one downward dolphin kick off the turns.)

'We All Studied Him'

Despite the success of Berkoff, Hyman and others, few coaches were tempted to try to maximize the available 15 meters of underwater opportunity. Some looked at the success of Berkoff and Hyman as something of a fluke, figuring that extra time underwater would provide only temporary gains. They thought swimmers would surge ahead but fade at the end of races out of pure exhaustion, particularly in races longer than 100 meters.

They also worried about safety; no one wanted swimmers passing out during practice while trying to hold their breath longer than usual.