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IIT Kanpur alum and George Washington University researcher
Rajat Mittal has spent the past five years studying Phelps and
his dolphin kick - also known as the 'Berkoff Blastoff' after the
Harvard backstroker who used it the first time at the Olympics
20 years ago.

It all began when Mittal, a professor of mechanical and aerospace
engineering, got involved in a US Navy project to study dolphins,
thought to be the ultimate swimmers. ''We were asked to
understand how fish swim so efficiently,'' Mittal recalled in an
interview Wednesday, ''and it seemed like a natural extension
to apply this to human swimming.''

In collaboration with USA Swimming, Mittal and his colleagues
began studying 50 American swimmers, eventually finding that of
all of them, Phelps was able to use his body ''in a way that is very,
very different from the other athletes...much closer to dolphins
than we have seen for any other swimmer.''

And just how does he do that? Phelps is able to straighten his
massive size 14 feet to a greater angle (about 15 degrees) than any
other swimmer, to reduce resistance. ''Almost 90 percent of all the
thrust is coming from the foot,'' Mittal explained. ''And the flatter
and bigger your foot is, you essentially have a bigger paddle.
Michael's foot size and the angle he generates with it plays a big
role in his ability to swim very well.''

So never again laugh at someone with big, flat feet. There’s gold in
them!

But foot-size isn’t the only reason behind the Phelps phenomenon.
Studies show that his powerful lungs can hold out longer
underwater than most swimmers, eliminating the splash and drag
that would result if he surfaced early. ''If the body is moving on the
surface, it creates waves,'' Mittal explained. ''So if you can move
underwater instead you can actually eliminate some resistance.''

The Harvard swimmer David Bergkoff figured this out first 20
years ago, using it effectively at the start and the turns to win
four Olympic medals, even as other swimmers copied the
technique. Swimming officials eventually imposed a limit of 15
meters underwater, a threshold Phelps exploits faster and better
than anyone else.


TOI