1. Center for Treatment of Rheumatic and Musculoskeletal Diseases (REMEDY), Diakonhjemmet Hospital, P.O. Box 23, Vinderen, No-0319 Oslo, Norway
2. Department of Orthopaedics, Rehabilitation and Physical Therapy, Leiden University Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
3. Basalt Rehabilitation, Vrederustlaan 180, 2543 SW The Hague, The Netherlands
4. Faculty of Healthcare, University of Applied Sciences, Zernikedreef 1, 2333 CK Leiden, The Netherlands