HONG KONG, March 19 (Reuters) - Chinese sports brand Li Ning Co Ltd posted a loss for a third year in a row as it invests in a restructuring plan, and said it has appointed executive chairman Li Ning as its interim chief executive.

Li Ning, which is backed by U.S. private equity firm TPG Capital and Singapore sovereign fund GIC, posted a net loss of 781.5 million yuan ($125.4 million) for 2014, compared with a 391.5 million yuan loss a year earlier.

The retailer warned in January that it expected to post a loss for 2014, due in part to the costs of its transformation plans, and the result was in line with analysts' forecasts.

Li Ning said full-year revenue rose 16 percent to 6.73 billion yuan, while its gross profit margin came in at 44.6 percent from 44.5 percent in 2013.

The company, which recently teamed up with Chinese smartphone maker Xiaomi to produce a new generation of "smart" running shoes, operated 5,626 retail stores in China as of end-December, 289 fewer stores than a year earlier.

($1 = 6.2289 Chinese yuan renminbi) (Reporting by Donny Kwok; Additional reporting by Shilpa Murthy; Editing by Richard Pullin)