1. Introduction Low back pain (LBP) is usually defined as pain localised below the costal margin (ribs) and above the inferior gluteal folds (buttock crease). It is the leading cause of disability worldwide and is becoming increasingly prevalent (Harkness et al. 2005, Hoy et al. 2012, Vos et al. 2012). Chronic low back pain (CLBP) is variously defined as lasting longer than 7-12 weeks, to 3 months (Anderrson 1999, Frymoyer 1988). LBP is typically classified as “specific” or “non-specific”. Specific LBP refers to symptoms caused by specific pathophysiologic causes, such as hernia nucleus, infection,...