| Study characteristics |
| Methods |
Study design: RCT
Setting: Netherlands, occupational
Exercise groups: 2
Comparison groups: 0 |
| Participants |
Number of participants: 81 (E1 = 41, E2 = 40)
Chronic LBP duration: Not specified (long)
Neurological/radicular symptoms: Some participants
Mean age (years): 41
Sex (female): 0% |
| Interventions |
Exercise Group 1 (E1): Progressive resistance exercises for the isolated lumbar extensor muscle groups (load set at 50% of maximal isometric extension strength of participant at baseline); type = strengthening; duration = 12 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = none
Exercise Group 2 (E2): Nonprogressive low‐intensity resistance exercise programme (load set at a maximum of 20% of the maximal isometric extension strength of participant at baseline); type = strengthening; duration = 12 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = none |
| Outcomes |
Core outcomes reported: Function (Roland‐Morris Disability Questionnaire); HRQoL (36‐Item Short Form Survey)
Follow‐up time periods available for syntheses: 12 weeks (short); 26 weeks (moderate) |
| Notes |
Conflicts of interest: Not reported
Funding source: Not reported
Other: Information modified for author contact |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
Randomisation was done by means of a computer‐generated table. |
| Allocation concealment (selection bias) |
Low risk |
The study is an observer‐blinded trial. |
| Blinding of participants and personnel (performance bias)
All outcomes |
High risk |
Not described |
| Blinding of care provider (performance bias) |
High risk |
Same physio delivered both programmes. |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
The training sessions and data collection (both from questionnaires and from strength measurements) were conducted by different people. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Six at post‐treatment, five more at six months, eight more at nine months = 62/81 total completed |
| Participants analysed in group allocated (attrition bias) |
High risk |
Analyses were done using all randomised participants who provided any post‐baseline data. |
| Selective reporting (reporting bias) |
Low risk |
Support for judgement was not available. |
| Groups similar at baseline (selection bias) |
Low risk |
Table 1 shows demographic properties of the population as well as baseline values for the outcome measures. |
| Co‐interventions avoided or similar (performance bias) |
Low risk |
Participants were asked to abandon other treatments In both groups; participants reported no co‐interventions during the 12‐week treatment period. |
| Compliance acceptable in all groups (performance bias) |
High risk |
The high‐intensity training group showed a higher treatment compliance than the low‐intensity training group: 29 participants (71%) in the high‐intensity training group, versus 19 participants (48%) in the low‐intensity training group |
| Timing of outcome assessment similar in all groups (detection bias) |
Low risk |
Support for judgement was not available. |
