Li 2008.

Study characteristics
Methods	Study design: RCT Setting: China, healthcare Exercise groups: 1 Comparison groups: 1
Participants	Number of participants: 20 (E1 = 10, C1 = 10) Chronic LBP duration: Not specified (not specified) Neurological/radicular symptoms: Some participants Mean age (years): Not reported Sex (female): 50%
Interventions	Exercise Group 1 (E1): Transversus abdominis muscle exercises; type = core strengthening; duration = 6 weeks; dose = low; design = individualised; delivery = individual; additional intervention = none Comparison Group 1 (C1): Usual care/no treatment ("traditional treatment")
Outcomes	Core outcomes reported: Function (Aberdeen Back Pain Scale) Follow‐up time periods available for syntheses: 6 weeks (short)
Notes	Conflicts of interest: Not reported Funding source: Not reported Other: None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not described
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not described
Blinding of care provider (performance bias)	Unclear risk	Not described
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not described
Incomplete outcome data (attrition bias) All outcomes	Low risk	Assumed from data given
Participants analysed in group allocated (attrition bias)	Low risk	Assumed all patients completed the study
Selective reporting (reporting bias)	Low risk	Support for judgement was not available.
Groups similar at baseline (selection bias)	Low risk	Support for judgement was not available.
Co‐interventions avoided or similar (performance bias)	Unclear risk	Not described
Compliance acceptable in all groups (performance bias)	Unclear risk	Not described
Timing of outcome assessment similar in all groups (detection bias)	Low risk	Support for judgement was not available.