1 Department of Sport and Rehabilitation Sciences, University of Liège, Liege, Belgium Faculty of Motor Sciencesn UCLouvain, Louvain-la-Neuve, Belgium Belgian Back Society (BBS).
2 Belgian Back Society (BBS) Rehabilitation Sciences and Physiotherapy Department, Hasselt University, Belgium.
3 Belgian Back Society (BBS) Department of Physiotherapy and Rehabilitation Sciences (MOVANT), Antwerp, Belgium.