Shares of Lululemon Athletica (LULU - Get Report)  hit new 52-week highs in Thursday's trading session after reporting fiscal first-quarter earnings.

However, the stock is sank off those highs -- even as the broader market is up on the day -- closing higher by "just" 2.1% at $174.52. With shares failing to hold a bulk of its gains after a strong quarter, it's got investors wondering if the stock's run is coming to an end.

After all, Lululemon stock is up 38% over the past year, easily crushing the S&P 500's return of 3.6%. It's also vastly higher than the returns from Nike (NKE - Get Report) and Under Armour (UA - Get Report) (UAA - Get Report) over the past 12 months, whose stocks are up just 12.3% and 10.2%, respectively.

Those questions are surfacing despite Lululemon's first-quarter earnings of 74 cents per share, topping analysts' expectations of 71 cents per share and growing 34.5% year-over-year. Revenue jumped 20% from the same period a year ago to $782.3 million and easily beat estimates of $756 million.

It wasn't just an impressive top- and bottom-line beat, though. Comparable-store sales surged 16%, beating estimates of 11%, while management lifted its full-year outlook. Remember how rosy management's forecast has been over the past few quarters? Well, it just keeps getting better.

So what's the problem?

Trading Lululemon Stock

Daily chart of Lululemon stock.
Daily chart of Lululemon stock.

Despite the increased guidance for Q2 and the full year, the numbers aren't as high as many had hoped. Analysts' estimates still sit at the high end of management's new Q2 outlook, while Lululemon's full-year outlook comes up a bit short of consensus.

That's likely why we're seeing the stock back off its highs, even though the quarter was as healthy as can be. That leaves bulls in a tricky spot. Do they buy Thursday's decline and view it as a mis-priced gift or do they use this opportunity to cash out ahead of more declines?

The good news is that Lululemon stock is holding up above its 20-day and 50-day moving averages, a sign that the bulls still have control of momentum. Those figures sit at $171.06 and $172.17, respectively.

If LULU stock loses those levels -- say $170 -- then it could signal a shift in momentum to the bears. As long as its holding this area, though, buyers appear OK. Short-term bulls can use this area as a low-risk stop on their position if they so choose. 

The stock briefly penetrated this level earlier, but $180 is the current ceiling. Above this mark puts Thursday's highs back on the table, with room to run should Lululemon stock hurdle this mark.

I wouldn't become too concerned with Lululemon stock unless it broke down below $160, a notable level of support and resistance over the past year. Further, losing this mark would break the "higher lows" theme we've seen since December (orange arrows).

The bottom line: North of $170 and Lululemon stock is OK. Below opens up a test of the key $160 level. Chopping between $160 and $180 wouldn't be the worst thing in the world either, as LULU stock digests its large rally.

Sarge: How to Trade Lululemon After Earnings

Behind the Label: From Yoga Studio to Yoga Pants to an Athleisure Empire: A History of Lululemon

This article is commentary by an independent contributor. At the time of publication, the author had no positions in the stocks mentioned.