Aug 6 (Reuters) - K-Swiss Inc (KSWS.O) posted a wider-than-expected quarterly loss, as international revenue nearly halved, and the athletic-shoes maker tightened its full-year outlook range.

Anna Kournikova for K-Swiss

"The environment at retail, as well as our brand's popularity, remain challenging and are evident in the continued year-over-year decline in sales, earnings and backlog," Chairman Steven Nichols said in a statement.

The company, which sells training, athletic, and children's shoes, apparel and accessories, reported a net loss of $11.5 million, or 33 cents a share, for the second quarter, compared with a profit of $26.4 million, or 75 cents a share, in the year-ago quarter.

According to Reuters Estimates, the company posted a loss of 30 cents a share, excluding items, compared with market estimates of a loss of 23 cents a share.

Revenue fell 35 percent to $54.0 million. Analysts expected revenue of $47.5 million.

K-Swiss now expects 2009 loss of 70 cents to 90 cents a share, on revenue of about $215 million to $230 million. Its prior forecast was 2009 loss of 60 cents to 90 cents a share, on revenue of about $200 million to $230 million.

Shares of the Westlake Village, California-based company closed at $10.85 Wednesday 5 August on Nasdaq. (Reporting by Vidya Lakshmi in Bangalore; Editing by Ratul Ray Chaudhuri)