1. Department of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
2. Department of Physiotherapy and Occupational Therapy, Næstved-Slagelse-Ringsted Hospitals, Slagelse, Denmark
3. Department of Internal Medicine, Division of Rheumatology Rush University Medical Center, Chicago, IL, USA
4. Research Unit of General Practice, Department of Public Health, University of Southern Denmark, Odense, Denmark