2. Details of exercise intervention.

Study	Exercise protocol	Back stretching	Leg stretching	Leg mobilization	Back mobilization	Abdomen strength	Back strength	Relaxation exercise	Back care advice
Cherkin 1998	9 times, supervision by physiotherapist	++	?	?	++	?	++	?	‐
Donchin 1990	45 minutes each session, 24 sessions, twice a week for 3 months, supervision by physical education instructor	‐	‐	‐	++	++	+	‐	+
Faas 1998	20 minutes each session, 10 sessions, twice a week for 5 weeks, supervision by physiotherapist	+	+	‐	+	+	+	‐	++
Hagen 2003	Protocol not mentioned, supervision by a physiotherapist	?	?	++	?	?	?	‐	+++
Hides 2001	8 sessions, twice a week	‐	‐	‐	?	+++	+++	‐	++
Kellett 1991	35‐45 minutes each session, supervision by physiotherapist and physical fitness instructor	+	+	+	+	+	+	+	+
Ljunggren 1997	15‐30 minutes each session, 144 sessions, triple a week for a year, supervision by physiotherapist	+	‐	++	++	++	++	++	‐
Soukup 1999	1 hour each session, 20 sessions, twice a week for first 7 weeks; once a week for last 6 weeks, supervision by physiotherapist	+	++	‐	++	++	++	+ Breathing relaxation	++
Stankovic 1990	20 minutes each session, 2 sessions, separated by 2 weeks	+	‐	‐	++	++	++	‐	+

Key: ‐ does not contain; + contains some of it; ++ consists mostly of it; +++ consists entirely of it