Tiger Woods' girlfriend Lindsey Vonn injured her knee while training for the winter Olympics that will be in Sochi, Russia and now her participation in the games could be up in the air going forward after her second serious injury to the knee.

Olympic downhill champion Lindsey Vonn partially tore her anterior cruciate ligament (ACL) and suffered a mild strain to her right knee after crashing during training on Tuesday, U.S. ski officials said on Wednesday.

How she responds to treatment will determine when the four time overall World Cup champion resumes training.

Vonn sustained the injuries, along with minor facial abrasions and scapular contusions, in a downhill training fall at the U.S. Ski Team Speed Center at Copper Mountain, a week before her scheduled return to racing following knee surgery.

"Vonn plans to rest for a few days before pursuing physical therapy," the U.S. Ski Team said in a statement.

"U.S. Ski Team medical director Kyle Wilkens reported her response to the therapy would ultimately determine the timetable for her return to active training."

Vonn was due to begin official downhill training for next week's World Cup races at Beaver Creek. The women's downhill, super-G and giant slalom are being contested from November 29-December 1.

The 29-year-old American tore ligaments in her right knee last February in a crash racing super-G at the world alpine championships in Schladming, Austria.

Vonn, who has been wearing a protective knee brace as she rounds back into shape, was aiming for a return to top form in time for the February 7-23 Sochi Olympics.

The champion skier, who lives in Vail, had been saying she was eager to return to competition and was at Sunday's National Football League game in Denver between the Broncos and Kansas City Chiefs along with her boyfriend Tiger Woods.

(Reuters)