1. School of Energy and Electronic Engineering, University of Portsmouth, Portsmouth PO1 2UP, UK
2. Institute of Orthopaedics and Musculoskeletal Sciences, Royal National Orthopaedic Hospital, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore HA7 4LP, UK
3. Biomedical Engineering Unit, Department of Physiology, Makerere University, Kampala P.O. Box 7072, Uganda
4. Faculty of Technology, University of Portsmouth, Portsmouth PO1 2UP, UK
5. Centre for Human Movement and Rehabilitation, School of Health and Society, University of Salford, Salford M5 4WT, UK
6. School of Science, Engineering and Environment, University of Salford, Salford M5 4WT, UK