J. Nijs, PT, PhD, Pain in Motion Research Group, Departments of Human Physiology and Physiotherapy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, and Department of Physical Medicine and Rehabilitation, University Hospital Brussels, Brussels, Belgium. Mailing address: Vrije Universiteit Brussel, Medical Campus Jette, Building F-Kine, Laarbeeklaan 103, BE-1090 Brussel...