1. Department of Orthopaedics and Traumatology University Hospital Basel Basel Switzerland
2. Department of Psychology and Sport Science University of Bielefeld Bielefeld Germany
3. Department of Biomedical Engineering University of Basel Basel Switzerland
4. Department of Clinical Research University of Basel Basel Switzerland
5. Department of Spine Surgery University Hospital Basel Basel Switzerland
6. Institute for Biomechanics, ETH Zürich Zürich Switzerland