1. KG Baker, PT, PhD, is Senior Lecturer, Department of Health Science, Faculty of Health, Science, and Technology, UNITEC, Private Bag 92025, Auckland, New Zealand. He was Lecturer, School of Physiotherapy, Faculty of Health Sciences, University of Sydney, when this article was written.
2. VJ Robertson, PT, PhD, is Associate Professor, School of Physiotherapy, La Trobe University, Bundoora, Victoria, Australia. She was Visiting Professor, Division of Physical Therapy, University of Miami, Miami, Fla, when this article was written
3. FA Duck, PhD, FIPEM, is Medical Physicist, Royal United Hospital, Bath, United Kingdom