1. Laboratory of Biomechanics & Ergonomics, Department of Physiotherapy, Faculty of Health Sciences, International Hellenic University, Alexander Campus, P.O. Box 141, 57400 Thessaloniki, Greece
2. Department of Public Health, Medical School, University of Patras, 26504 Patra, Greece
3. Biomedical Engineering Department, Faculty of Engineering, Strathclyde University, Glasgow G4 0NW, UK