Study	Reason for exclusion
Alexandre 2001	The exercise group received other intervention (back school).
Amako 2003	All of the included subjects had no low‐back pain at entry of the study.
Buchbinder 2002	The article is a synopsis.
Cairns 2006	The exercise group received other interventions such as manual therapy, electrotherapy, and lumbar traction.
Gundewall 1993	The subjects did not experience back pain before. Impossible to extract recurrences from the data.
Helewa 1999	All of the included subjects had no low‐back pain at entry of the study.
Hides 1996	The exercise group received other non‐exercise interventions such as medications (analgesics). No interest outcomes were found in the study.
Hlobil 2005	Behavioural approach was co‐intervention.
Kofotolis 2005	The article is a review.
Koumantakis 2005	No relevant outcome was found in the study.
Koumantakis 2005a	No relevant outcome was found in the study.
Kuukkanen 2000	No relevant outcome was found in the study.
Leclaire 1996	In both arms physiotherapy was a co‐intervention.
Maul 2005	No relevant outcome was found in the study.
Medina 1995	The exercise group received other non‐exercise interventions.
Sjogren 2006	No relevant outcomes were found in the study.
Staal 2004	Behavioural approach was co‐intervention.
Suni 2006	No relevant outcome was found in the study.