1. JMA Mens, MD, is Researcher, Department of Rehabilitation Medicine, Faculty of Medicine, Erasmus University, Rotterdam, the Netherlands, and Head, Department of Spine Rehabilitation, Spine and Joint Centre, Westerlaan 10, 3016 CK, Rotterdam, the Netherlands.
2. CJ Snijders, PhD, is Professor of Medical Technology and Head, Department of Biomedical Physics and Technology, Faculty of Medicine and Allied Health Sciences, Erasmus University
3. HJ Stam, MD, PhD, is Professor of Medical Rehabilitation and Head, Department of Rehabilitation Medicine, Institute of Rehabilitation Medicine, University Hospital Rotterdam, Erasmus University