| Study characteristics |
| Methods |
Study design: RCT (NCT00447668)
Setting: USA, mixed
Exercise groups: 2
Comparison groups: 1 |
| Participants |
Number of participants: 228 (E1 = 92, E2 = 91, C1 = 45)
Chronic LBP duration: Not specified (long)
Neurological/radicular symptoms: No participants
Mean age (years): 48
Sex (female): 64% |
| Interventions |
Exercise Group 1 (E1): Viniyoga: 17 relatively simple postures with variations and adaptations, classes include breathing exercises, 5‐11 postures, and guided deep relaxation; type = yoga; duration = 12 weeks; dose = high; design = standardised; delivery = group; additional intervention = none
Exercise Group 2 (E2): Stretching classes consisting of 15 exercise designed to stretch major muscle groups (52 minutes of stretching) and 4 strengthening exercises; type = stretching & strengthening; duration = 12 weeks; dose = high; design = standardised; delivery = group; additional intervention = none
Comparison Group 1 (C1): Other conservative treatment (education) |
| Outcomes |
Core outcomes reported: Pain (bothersomeness); function (Roland‐Morris Disability Questionnaire); Global Perceived Health or Recovery (Global Perceived Health or Recovery (global rating of improvement))
Follow‐up time periods available for syntheses: 12 weeks (short); 26 weeks (moderate) |
| Notes |
Conflicts of interest: Not reported
Funding source: National Center for Complementary and Alternative Medicine (Cooperative Agreement Number U01 AT003208 M)
Other: SDs imputed |
| Risk of bias |
| Bias |
Authors' judgement |
Support for judgement |
| Random sequence generation (selection bias) |
Low risk |
After completing the baseline interview at Group Health facilities, participants within each recruitment cohort were randomised by a research assistant. |
| Allocation concealment (selection bias) |
Low risk |
After completing the baseline interview at Group Health facilities, participants within each recruitment cohort were randomised by a research assistant. |
| Blinding of participants and personnel (performance bias)
All outcomes |
High risk |
Assumed not possible |
| Blinding of care provider (performance bias) |
High risk |
Assumed not possible |
| Blinding of outcome assessment (detection bias)
All outcomes |
Low risk |
Telephone interviews were conducted by masked interviewers at baseline and at six, 12, and 26 weeks after randomisation. |
| Incomplete outcome data (attrition bias)
All outcomes |
Low risk |
Overall follow‐up rates were 90% or 91% at all time points. |
| Participants analysed in group allocated (attrition bias) |
Low risk |
All analyses were conducted assuming intention‐to‐treat principles using SAS statistical software (version 9 2; SAS Institute Inc, Cary, North Carolina). |
| Selective reporting (reporting bias) |
Low risk |
Support for judgement was not available. |
| Groups similar at baseline (selection bias) |
Low risk |
Baseline characteristics were well balanced across groups, except the yoga group had greater back dysfunction (Table 1). |
| Co‐interventions avoided or similar (performance bias) |
Low risk |
Compared with baseline, roughly a quarter to a third fewer participants in the yoga and stretching groups reported using any medications for back pain. |
| Compliance acceptable in all groups (performance bias) |
Low risk |
Participants randomised to yoga were more likely than those assigned to stretching to attend at least one class (95% vs 82%, respectively) (Figure 1). |
| Timing of outcome assessment similar in all groups (detection bias) |
Low risk |
Support for judgement was not available. |
