[1] Montecatone Rehabil Inst, Spinal Unit, Bologna, Italy
[2] Bielefeld Univ, Sch Publ Hlth, Bielefeld, Germany
[3] Swiss Parapleg Res, Nottwil, Switzerland
[4] ICF Res Branch, Nottwil, Switzerland
[5] Univ Luzern, Dept Hlth Sci & Med, Luzern, Switzerland
[6] Univ La Statale, Dept Biomed Surg & Dent Sci, Via Festa del Perdono 7, I-20122 Milan, Italy
[7] IRCCS Ist Ortoped Galeazzi, Milan, Italy