Table 4.

Criteria list used to assess the quality of the intensive group training protocol

1	At least two or more criteria have been set (focussed on activities or participation)
2	Duration, intensity, frequency etc. were formulated in the treatment goals
3	Reducing pain was not adopted as a treatment goal
4	The treatment goals were evaluated (whether goals are met is registered)
5	A minimum of two baseline measurements were performed
6	A treatment agreement (with goals) was signed by patient and physiotherapist
7	Information on dealing with (chronic) pain was provided
8	A minimum of 15 group training sessions (75%) were attended
9	Patient trained in a group
10	Graphs were used during training sessions and evaluations
11	A gradually progressive exercise scheme was prepared
12	There was/were plausible reason(s) for not following the progressive exercise scheme
13	At least one aerobic exercise was included in the scheme
14	At least one back exercise was included in the scheme
15	At least one abdominal exercise was included in the scheme
16	At least one buttock exercise was included in the scheme
17	A minimum of two evaluations were performed
18	No other (manual) therapies for low back pain were performed

One point was assigned to each positively assessed Item; the maximum score was 18. For adoption in the per protocol analysis a minimum of 14 points were necessary