1. Amsterdam Rehabilitation Research Centre; Reade Amsterdam The Netherlands
2. Amsterdam Rehabilitation Research Centre, Reade, and VU University Medical Centre, EMGO Institute; Amsterdam The Netherlands
3. VU University Medical Centre, EMGO Institute; Amsterdam The Netherlands
4. University of Jyväskylä and Jyväskylä Central Hospital; Jyväskylä Finland
5. University Medical Centre Utrecht; Utrecht The Netherlands
6. University of Alberta; Edmonton Alberta Canada