If you think 50% growth is for tech stocks only, then you haven't been paying attention to what's going down at Nike (NYSE:NKE) these days.

For its third fiscal quarter, Nike posted 21% revenue growth and earnings made a Jordan-like -- or maybe we should pass the torch and say James-like -- jump to $0.74 per share, a 57% increase. Sure, the firm had already leaked most of this good news earlier in the month, but the official release contains other interesting tidbits, like a nice 1.4% improvement in gross margins and a 0.9% reduction in SG&A expenses.

Efficiency gains like these should soothe some who wondered if Nike has lost its mind, given the amount of money it's throwing at up-and-coming spokes-athletes. In my opinion, these are valid criticisms: Even though LeBron James has put up stellar numbers, going strictly by the books, his new shoe line still doesn't take in what Nike's putting out.

In fact, footwear sales in the U.S. eked up just a single point in the latest quarter. Equipment, Nike's smallest slice of the revenue pie, grew most quickly here at home, but the total uptick still only came in at 4%. Exchange-rate roulette helped juice overseas sales, including a 36% revenue upswing in Europe, of which nearly a third was owed to currency fluctuations. In Asia, where apparel sales grew at twice the footwear rate, the overall sales increase reached 21%, half of it due to the dropping dollar.

Notice the theme? It's reprised in the firm's forward outlook. The 9.9% gain in worldwide future orders that's today's headline darling owes 40% to the funny money situation as well. That's what makes me think Nike's stock, at a P/E of 23, might be a bit expensive these days. I'm partial to its smaller, nimbler competitor Reebok (NYSE:RBK), which trades at a lower multiple -- under 17 -- with a similar growth outlook.

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Fool contributor Seth Jayson misses that old blaze-orange Nike cross-country shoe with the waffle sole. He owns no stake in any companies mentioned above. View his Fool profile here.