1. a Division of Physiotherapy , Linköping University , SE-581 83, Linköping, Sweden
2. c Division of Industrial Ergonomics , Royal Institute of Technology, School of Technology and Health , Nobels Allé 10, S141-52, Huddinge, Sweden
3. b Division of Industrial Ergonomics , Linköping University , SE-581 83, Linköping, Sweden