1. Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
2. Musculoskeletal Research Laboratory, VA Palo Alto Health Care System, Palo Alto, CA, USA
3. Centre for Rehabilitation Engineering and Assistive Technologies, University College London, Stanmore, UK
4. Nuffield Department of Surgical Sciences, University of Oxford, Oxford, UK
5. Biomedical Engineering Group, School of Engineering, Warwick University, Coventry, UK
6. Department of Electrical and Computer Engineering, New Jersey Institute of Technology, Newark, NJ, USA