Shares of Quiksilver (NYSE:ZQK), the designer and marketer of surf-and-skate-inspired apparel, rose nearly 7% in Tuesday trading following the announcement of upbeat fiscal second-quarter financial results and an improved financial outlook for the balance of the fiscal year. The company's numbers underscore the continued strength of its youth-oriented market segment, which has boosted its shares -- as well as those of companies like Pacific Sunwear (NASDAQ:PSUN) and Skechers (NYSE:SKX) -- in recent months.

Revenues for Q2 (ended April 30) rose 23% to nearly $323 million -- significantly more quickly than inventories, which were up only 5% year-over-year, and receivables. Net income improved a neat 23% to $27.8 million. Sales rose worldwide, including a solid 16% jump in the United States, and management expressed continued pleasure with the potential of the March acquisition of DC Shoes, which it picked up during the quarter. Gross margins improved, and while operating margins slipped somewhat, net margins held fast thanks to strong top-line growth.

Looking forward, the company boosted its second-half guidance: Quiksilver is now pointing investors toward full-year sales of $1.19 to $1.2 billion, and full-year EPS of between $1.27 and $1.29. Last year the company turned in $975 million of sales and $1.03 of EPS, so the new guidance would represent growth of approximately 22% and 23%, respectively -- pretty solid numbers.

While investors are clearly on to this story, there may still be room to run: Quiksilver's projected sales and earnings growth is impressive, as is its ability to grow business overseas and make acquisitions, a good use of capital. The company's shares currently fetch a multiple of about 19 times projected EPS, and perhaps the only thing holding it back from a richer valuation is that it still carries significant long-term debt that cuts into profits.

Fool contributor Dave Marino-Nachison doesn't own any of the companies in this article.