(CNN) — U.S. ski queen Lindsey Vonn crashed Tuesday on a training run at Copper Mountain in Colorado.
Her condition was not immediately clear.
“She is being evaluated. We’ll have a report once we know more,” said Tom Kelly, a spokesman for the U.S. Ski and Snowboard Association.
The Olympic downhill champion was preparing to return to competitive racing after a serious knee injury this year.
Vonn was airlifted to a hospital in February after she landed heavily on her right knee on the opening day of the Alpine Ski World Championships in Austria. She underwent surgery for knee reconstruction.
Vonn was crowned America’s snow queen when she became the first American woman to win the Olympic downhill title at the Vancouver Games in 2010.
She followed up her Vancouver victory with a stellar World Cup season in 2011-2012, winning 12 races and the overall title with a new record points haul.
A combination of illness and injury disrupted Vonn’s dominance on the slopes last season. She planned to return at the World Cup event in Beaver Creek, Colorado on November 29.