1. Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen, Kalfarveien 31, 5018 Bergen, Norway
2. Department of Health and Social Sciences, Western Norway University of Applied Sciences, Bergen, Norway
3. Department of Epidemiology and Biostatistics and EMGO+ Institute for Health and Care Research, VU Medical Centre; and Department of Health Sciences, Faculty of Earth and Life Sciences, EMGO+ Institute for Health and Care Research, VU University, Amsterdam, the Netherlands
4. Department of Epidemiology and Biostatistics and EMGO+ Institute for Health and Care Research, VU Medical Centre
5. Physiotherapy Research Group, Department of Global Public Health and Primary Care, University of Bergen