a Moss Rehab Gait & Motion Analysis Laboratory, Department of PM&R, Elkins Park, PA, USA;
b Cerebral Palsy Institute, School of Medicine, University of Notre Dame Australia, Darlinghurst, Sydney, New South Wales, Australia;
c Neurosciences, University of California, San Diego, California, USA;
d Centre for Musculoskeletal Studies, School of Surgery, The University of Western Australia, Perth, Australia;
and e North Staffordshire Rehabilitation Centre, University Hospital of North Staffordshire (Haywood Hospital), Stoke on Trent, UK