1 Matt Wallden Health & Performance, Surrey, UK. Electronic address: matt@mattwallden.com.
2 Pain in Motion Research Group (PAIN), Department of Physiotherapy, Human Physiology and Anatomy, Faculty of Physical Education & Physiotherapy, Vrije Universiteit Brussel, Belgium; Chronic Pain Rehabilitation, Department of Physical Medicine and Physiotherapy, University Hospital Brussels, Belgium; Department of Health and Rehabilitation, Unit of Physiotherapy, Institute of Neuroscience and Physiology, University of Gothenburg Center for Person-Centred Care (GPCC), Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.