Skechers, USA (SKX) reports earnings today after the market close. The fashionable shoe maker has been on fire in 2009, and its shares have followed suit.

It is always difficult to buy a stock that has gone parabolic. Investors rightly should be skeptical of future gains and the sustainability of huge profit runs. The concern is obvious. What happens when the music stops?

There are too many stories of rising stars crashing and burning. Of course, the flip side is that investors that can ride the wave can make good money doing so. It is tricky business knowing when to say when.

That is why earnings are so very important. It is even more important for the fast-growing company whose shares have appreciated greatly in value.

Since bottoming in March around $5 per share, SKX has rallied fantastically to its current price of $22 per share. That huge gain corresponds to improvements in sales and earnings as recorded in company profit releases.

For the quarter ending September, the company is expected to post a profit of $.35 per share. Given that many retail plays have beaten earnings, it is likely that SKX will beat that number when it announces its results today.

What will happen to the stock with that beat?

Some could argue that much of the expectation is already priced into the stock. On a trailing basis, shares are now priced in nosebleed territory.

That said, one must look a bit deeper to determine if SKX’s run can continue. The odds are likely that it will.

For the year ending December 31, SKX is expected to make $.49 per share, but that number jumps to a whopping $1.11 per share in 2010. With the economy on more stable ground, and a consumer that still finds SKX quite attractive, the company should beat these expectations.

On a forward basis looking at 2010 estimates, SKX trades for a reasonable 20 times earnings. Not bad, considering the expectation is for profits to double.

Again, the issue here is can the company deliver impressive growth going forward in 2011 and beyond? The answer is yes, assuming the company beats on a quarterly basis.

Any signs that results are slipping and SKX shares will drop in value. Historically, investing in parabolic growth at the curve of the hockey stick can be done reliably for at least several quarters.

I’m expecting a strong report from SKX today that will likely continue for the next year.