Berchtesgaden (pps) Due to chronic back troubles Sonja Wiedemann, who surprisingly captured the 1999 World championship title in Koenigssee, has now ended her career. At the 2000 Worlds in St. Moritz she won the bronze medal. The 26-year old athlete who finished in fourth position at the 2001 Worlds in Calgary, has won three events of the Viessmann Luge World Cup (Calgary 1999/2000, Igls 2000/2001 and Lake Placid 2001/2002). Prior to the success on her home track, Sonja Wiedemann had never competed in a World Cup event.