In May 1999 Annika, as part of the senior group, took 6th place in the All-Around, 5th place with 5 pair of clubs and 4th with 3 ribbons and 2 hoops with the group at the European Championships.[2] At the World Championships in Osaka they were 5th in the All-Around, 5th with 10 clubs and 7th with 3 ribbons and 2 hoops, thus qualifying for the following year's Olympics.[3][4] At the time she lived in Bochum, with the Ülengin family, along her teammate Jeanine Fissler.[5]
Annika and her teammates Friederike Arlt, Susan Benicke, Jeanine Fissler, Jessica Schumacher and Selma Neuhaus achieved a surprising fourth place at the 2000 Sydney Olympics, this was the best ever rhythmic gymnastics result in German Olympic history.[6]
Seibel studied sports in Cologne and became a graduated sports and yoga coach. She also participated in show dancing events and worked with the agency of her former coach Carmen Weber in Ratingen.[7]
Germany