NEW YORK (CNN/Money) - As the Summer Olympics gets underway, it's time to consider the true powerhouse in international sports.

It's not the United States, Russia, Germany or China. The clear winner in all forms of athletic competition is Nike Inc. (NKE: Research, Estimates)

The Beaverton, Ore.-based company is the global leader in athletic footwear.

And in the U.S., Nike is now No. 1 in its four major market segments -- footwear, branded apparel, licensed apparel and sports equipment. Nike took the lead in the equipment category during the course of the last year.

But Nike's products, like its famous athlete endorsers, face tough competition from other well-known brands. And the stock has already enjoyed a run-up worthy of an Olympic champion, gaining nearly 35 percent during the past 12 months.

Can Nike keep up its winning ways? See what we think in this week's Buy What You Know? »»

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