1. W Ter Woerds, MSc, is a medical student at Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
2. PCE De Groot, PhD, is Post-Doctoral Fellow, Department of Physiology, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, Nijmegen, the Netherlands
3. DHJM van Kuppevelt, MD, is Physician, Rehabilitation Centre Maartenskliniek, Nijmegen, the Netherlands
4. MTE Hopman, MD, PhD, is Associate Professor, Department of Physiology, Radboud University Nijmegen Medical Centre