1. RJ van den Berg-Emons, PhD (Health Science), is Research Scientist, Department of Rehabilitation Medicine, Erasmus Medical Center Rotterdam, Dr Molewaterplein 40, 3015 GD Rotterdam, the Netherlands .
2. JB Bussmann, PhD (Medicine and Health Science), BSC (PT), is Research Scientist, Department of Rehabilitation Medicine, Erasmus Medical Center Rotterdam
3. AH Balk, PhD (Cardiology), is Cardiologist, Department of Cardiology, Erasmus Medical Center Rotterdam
4. HJ Stam, PhD (Medicine and Health Science), MD (Medicine and Health Science), is Professor of Rehabilitation Medicine and Head of the Department of Rehabilitation Medicine, Erasmus Medical Center Rotterdam