1. North Wales Centre for Primary Care Research; Bangor University; Bangor UK
2. School of Sport, Health and Exercise Sciences; Bangor University; Bangor UK
3. Department of Sport and Exercise Science; University of Portsmouth; Portsmouth UK
4. Peter Maddison Rheumatology Centre; Betsi Cadwaladr University Health Board; Llandudno UK
5. Radiology Department; Betsi Cadwaladr University Health Board; Bangor UK
6. School of Medical Sciences; University of New South Wales; Sydney NSW Australia