1. Department of Orthopedics and Trauma Surgery, Faculty of Medicine, University Hospital, Albert-Ludwigs-University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany
2. Institute for Exercise- and Occupational Medicine, Faculty of Medicine, University Hospital, Albert-Ludwigs-University of Freiburg, Hugstetter Strasse 55, 79106 Freiburg, Germany