1. Department of Physiotherapy and Occupational Therapy, Aarhus University Hospital, Aarhus N, Denmark
2. Department of Clinical Medicine, Aarhus University, Aarhus N, Denmark
3. Department of Health Sciences, Brunel University London, London, UK
4. Imperial College NHS Healthcare Trust, London, UK
5. Faculty Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Netherlands