Why have investors soured on fitness-apparel retailer lululemon athletica (NASDAQ:LULU)?

The shares are trading at a third of last year's high, but you wouldn't know it going by this morning's healthy quarterly showing. Net revenue soared 48% to $85.5 million. Profits more than doubled, with earnings at $0.18 a share, before a $0.02-per-share hit from bowing out of the unreceptive Japanese retail market.

Analysts expected more on top, but they were looking for the high-end yoga-centric chain to generate net income of just $0.13 a share. The company has blown past Wall Street's profit targets in every quarter since going public last year, save for three months ago, when it simply met the market's estimates.  

The company's healthy expansion efforts continue, but that's not the only reason for the stellar growth. Comps during the quarter rose by 18%, or a still-impressive 13% store-level gain on a constant-dollar basis.

It's not just the yoga niche that's working. Retailers with stakes in yoga apparel, such as Liz Claiborne's (NYSE:LIZ) prAna, and VF's (NYSE:VFC) Lucy, and yoga instructional-DVD maker Gaiam (NASDAQ:GAIA), aren't setting the world on fire.

Obviously, the depressed share price at lululemon proves that it, too, is mortal, but are the markdowns warranted? The company has come under fire in its brief public life over iffy seaweed fiber apparel claims and padded resumes, but the healthy comps prove that customers don't seem to care.

The company is looking to earn between $0.68 a share and $0.71 a share this year. Analysts see a profit of $0.71 a share, and we already know that the chain's brief history exposes the pros as conservative estimators.

At its peak, lululemon may have had an unjustifiable valuation, but it now fetches just 18 times next year's expected earnings of $1.01. That's a premium to other mall clothing chains such as Abercrombie & Fitch (NYSE:ANF), American Eagle Outfitters (NYSE:AEO), and Aeropostale (NYSE:ARO), but it's a discount to the company's long-term earnings-per-share growth rate in excess of 25%. Obviously, it's also growing well ahead of that rate in the near term.

Unless the fundamentals begin to crack, investors have a great opportunity to pick up a rapidly growing retailer that's bucking the economic malaise at a spectacular price. Investors soured on lululemon in the past, but today's opportunity is pure sweetness.

Other ways to get fit, financially fit:

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Longtime Fool contributor Rick Munarriz doesn't believe that he has the patience and focus to excel at yoga. He does not own shares in any of the stocks in this story. He is part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.