Characteristics of primary studies included in the systematic reviews.

LBP: low back pain; SPLBP: specific low back pain; NSLBP: non-specific low back pain; SP: spine pain; EMG: electromyography; GP: general practitioner; includes all primary care-based physician care; Specialized unit: specialist, specialized unit at a hospital; VAS: visual analogue scale; RMQ: Roland Morris Disability Questionnaire; SF-36: Multi-purpose short-form health survey; McGill: McGill Pain Questionnaire; ODI: Oswestry Disability Index; FAB: fear avoidance beliefs.*Values are calculated as the mean of the mean values reported in the primary trials; the range of the mean values are shown.