Dual Olympic gold medallist Kristina Vogel, one of Germany's top track sprinters, was seriously injured during training in a collision with another cyclist on the Cottbus velodrome on Tuesday.
Vogel, 27, who was training with four-time junior world champion Pauline Grabosch, began an acceleration but collided with another rider who suddenly entered the track and crashed onto the concrete track.
According to Sportschau.de, Vogel was taken to the hospital in Cottbus, but then was airlifted to Berlin's trauma center.
"We are very worried about Kristina, it looks very bad," said national team coach Detlef Uibel told the German press agency.
Her manager Jörg Werner confirmed that Vogel was badly injured but offered no further details.
It is not the first serious injury of Vogel's career. Nine years ago, she was hit by a vehicle while training on the road and was in an induced coma for two days, suffering a broken vertebrae, broken jaw and fractures to her arm and hands.
She overcame the injuries to claim 11 world championship titles and three Olympic medals in the sprint events.