Michael Phelps has the perfect body for swimming, but that's not the only reason he's so good

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Michael Phelps is the most decorated Olympian ever, and his medal count at the Rio Olympics has continued to climb.

The swimmer has long been the modern Olympian with the most individual records. Now, he's even coming up against records set 2,168 years ago. As of August 10, Phelps had tied the ancient record set by Leonidas of Rhodes for the most individual wins (12). And he still has a couple more events to go.

So what makes Phelps such an incredible swimmer?

Many have pointed out that he has a perfect physique for swimming, and they're not wrong:

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In sports in general, there has been a sort of a "size sort" over recent decades, where athletes have started to focus on sports that they have an ideal body type for, Dr. Michael Joyner, a physician and Mayo Clinic researcher who is one of the world's top experts on fitness and human performance, told Business Insider.

Interestingly, said Joyner, elite performers in certain sports tend to be about the same size, as you can see if you look at rowers, gymnasts, and of course, swimmers.

Phelps certainly fits the bill.

But there has also been unproven speculation out there that Phelps has extreme qualities that make him such a good swimmer, such as the myth that he has double the lung capacity of the average human. (There's no actual evidence for this, and Dr. H. Richard Weiner, a swimmer and former team physician who practiced sports medicine at the University of Wisconsin-Milwaukee, previously told Scientific American that some of the claims about Phelps border on the ridiculous.)

While Phelps is certainly built for swimming, most of his competitors are too. They're tall, strong, long-armed, and frequently have longer-than-average torsos and relatively shorter legs. As "The Sports Gene" author David Epstein pointed out in a TED talk, even star water polo players share physiology that's different from the average person.

But it takes more than just build to get to where Phelps is.

As Weiner explained to Scientific American, physical advantages aren't sufficient on their own. You also have to have talent and technique, like Phelps' excellent stroke mechanics.

If you've watched Phelps during the Rio Olympics, you'll see that he has intense focus, drive, and a competitive nature too. All of those seem to be pretty important characteristics of a top Olympian.

It's the combination of all these factors that makes Phelps such an amazing athlete. Yes, his body is partly responsible, but that's not all.