SPORTS: Want to "Be Like Mike" in the Pool? Research Points to Fingers

By Karin Zeitvogel

As Michael Phelps' Olympic career comes to a close - the greatest competitor in his sport, like his idol, Michael Jordan - is there anything other swimmers do if they want to "be like Mike"? Duke University engineering professor Adrian Bejan has one answer.

Researcher Points to Fingers for a Faster Swim

Watch this video of Michael Phelps swimming, and you'll notice that his fingers are slightly spread as he slices through the water.

Phelps instinctively swims with forked hands. As published in a recent study, Bejan found that swimming with fingers apart can result in a whopping 53% increase in total force.

By spreading his fingers in the water,
Phelps creates an "invisible web"
that helps him swim faster

If the distance between the fingers is just right – roughly half the diameter of each finger – it creates an invisible web between digits, which gives the swimmer a boost in force and faster speed in the water, Bejan said.

“The finger moves through the water and a sheath of water essentially moves with it, creating a finger that looks thicker than it really is. Think of it like honey stuck to a spoon,” he told Water Citizen in a phone interview.

Greater force is the key to going faster in the water, and producing greater force is the job of the hands, Bejan said.

“A faster swimmer is one who creates a bigger wave above the water.  You need force to lift yourself above the water, and you get that by having greater downward force from your hands,” Bejan concluded.

In essence, the bigger the hands, the greater the force. And, “If you want a palm that is bigger, you want bigger fingers,”Bejan said. Spreading them slightly in the water achieves that.

Phelps spreads his fingers instinctively but many coaches these days tell their swimmers to do so. If a lot of people in the lap lanes at the local pool are contemplating their hands, you know why.

Constructional Law Governs Swimmers … and Anything Else That Moves

The swimmers’ fingers principle is based on the constructal law, devised by Bejan in 1996. Bejan published the results of his story in the June issue of the Journal of Theoretical Biology, Bejan and coauthor Sylvie Lorente of the University of Toulouse in France.

Constructional law holds that "anything that moves, from rivers to trucks to highways to swimmers and runners, does so with morphing configurations that allow movement to be easier and easier," said Bejan.

The results of the fingers study show that a slight adjustment in body configuration can bring a “significant change in force,” Bejan said.

He wondered if the next swimming aid will be tiny wedges that sit between swimmers’ fingers to hold them just the right distance apart.

Body Type and Family Heritage Also Important Factors

Finger spread is just one of Phelps’s secrets, of course. Phelps and other Olympic athletes owe much of their success to body types, which are tied to their family heritage.

His hands are said to be the size of dinner plates even without the invisible inter-finger webbing.  Like most champion swimmers, he’s tall, – 6 ft. 4 in. (1.93 meters).  Phelps also has size 14 (Eur 47) feet, a 6 ft. 7 in. (2 meters) arm span, a long torso and comparatively short legs.

In 2008, Bejan used the constructal law to predict the triumphs of “bigger, taller athletes” like Phelps at the Beijing Olympics.

Two years later, Bejan, who’s originally from Romania, teamed up with Edward Jones, an African American professor at Howard University in Washington, to use the constructal law to explain why whites dominate in the pool and blacks of West African origin, like Jamaica’s Usain Bolt, in sprint-distance track events.

Consideration of race and national origin as a predictor of athletic success has been a controversial subject.  While the speed with which an athlete moves through water or air is not impacted by color, the athlete’s mass, and distribution of that mass, does make a difference.

In the study completed by Bejan and Jones, the researchers found that "the swimmer who makes the bigger wave is the faster swimmer, and a longer torso makes a bigger wave. Europeans have a three-percent longer torso than West Africans, which gives them a 1.5-percent speed advantage in the pool."

Individuals of West African origin, meanwhile, have longer legs than people of European origin. That puts their center of gravity – roughly speaking, the belly button – around three centimeters (1.18 inches) higher than whites', said Bejan.

“Locomotion is essentially a continual process of falling forward, and mass that falls from a higher altitude falls faster,” he said.

Body Type, Forked Fingers, and the X Factor

In the months up to the London Olympics, Bejan says he had been inundated with emails and calls from people asking him to predict who will climb to the highest step of podiums at the Games.

As predicted by science, many of the winning Olympians were tall and svelte, and the swimmers probably spread their fingers in the water, as Bejan predicted.In the end, for many of the Olympic races, the final determining factor was simply the sheer will to win.

Something to remember when you're racing friends in your own pool.  And don't forget to spread your fingers!