1. SW Muir, BSc, BScPT, is a PhD candidate, Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, University of Western Ontario, Kresge Building, London, Ontario, Canada N6A 5C1
2. K Berg, PT, PhD, is Chair and Associate Professor, Department of Physical Therapy, University of Toronto, Toronto, Ontario, Canada
3. B Chesworth, BA, BScPT, MClScPT, PhD, is Assistant Professor, School of Physical Therapy, Faculty of Health Sciences, University of Western Ontario
4. M Speechley, PhD, is Associate Professor, Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, University of Western Ontario