Salamat 2017.

Study characteristics
Methods	Study design: RCT (IRCT2013121615822N1) Setting: Iran, healthcare Exercise groups: 2 Comparison groups: 0
Participants	Number of participants: 32 (E1 = 16, E2 = 16) Chronic LBP duration: Not specified (not specified) Neurological/radicular symptoms: Not specified Mean age (years): 36 Sex (female): Not reported
Interventions	Exercise Group 1 (E1): Stabilisation exercises: co‐ordinated training and independent activity of deep trunk muscles including transversus abdominis and multifidus in pain‐free positions and movements, also done at home; type = core strengthening; duration = 4 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = none Exercise Group 2 (E2): Movement control exercises: dissociation of lumbo‐pelvic movement from thoracic movement in order to reduce excessive lumbar extension, training to perform everyday and work tasks without abnormal bracing or breathing, daily exercises at home; type = functional restoration; duration = 4 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = none
Outcomes	Core outcomes reported: Pain (Numerical Rating Scale); function (Oswestry Disability Index) Follow‐up time periods available for syntheses: 4 weeks (short)
Notes	Conflicts of interest: Not reported Funding source: Rehabilitation School, Tehran University of Medical Sciences Other: None
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation method was not described enough to make an assessment of adequacy; only description was that randomisation was achieved "via a random number sequence".
Allocation concealment (selection bias)	High risk	Not enough information on the randomisation and treatment allocation methods to assess
Blinding of participants and personnel (performance bias) All outcomes	Low risk	1. Patients were not blind to intervention because the interventions were too different for patients not to know the difference, however the team "Attempt[ed] to keep subjects blind to their group assignment"; 2. Both groups getting sufficient treatment, unlikely to be dissatisfied; difficult to access outside of study context
Blinding of care provider (performance bias)	Low risk	1. "The treating therapist was not blind to the treatment group of the subjects" (treating therapist = care providers); 2. Explicit set of exercises in protocol; no decision by care provider; since there wasn't a favoured intervention prior, unlikely that providers tried to "balance" care
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	1. Outcome assessors were the patients for outcomes pain and disability, they were not blinded; 2. Pain and functional questionnaires are subjective, and responses could be altered by awareness of intervention; 3. Because there was no clear "better" intervention between the two, it is unlikely that the lack of patient blinding led to a serious biasing of judgement for outcome assessment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1. Dropout rate (25%) was borderline unacceptable for a short‐term follow‐up (four weeks); 2. Evidence that the analysis was not biased by missing data: the dropout rate was identical for both treatment groups, and dropout reasons were unrelated to low back pain.
Participants analysed in group allocated (attrition bias)	Low risk	1. Intention‐to‐treat analysis was included; all patients were analysed according to the treatment to which they were randomised.
Selective reporting (reporting bias)	Low risk	1. No linked protocol found but within this paper all outcomes and analyses fully reported; no obvious omissions
Groups similar at baseline (selection bias)	Low risk	Groups were similar at baseline on age, body mass index, pain and disability, but did not report sex or duration of back pain symptoms at baseline.
Co‐interventions avoided or similar (performance bias)	High risk	No information on how the study dealt with co‐interventions (or if they existed) was reported.
Compliance acceptable in all groups (performance bias)	High risk	Compliance was not reported, so it was difficult to assess its acceptability; intervention was supervised, which tends to increase compliance.
Timing of outcome assessment similar in all groups (detection bias)	Low risk	1. All outcome assessments were similarly timed and measured for all treatment groups; 2. Numeric Rating Scale (for pain) and Oswestry Disability Index (for disability) are well‐validated tools in the low back pain field.
Other bias	Low risk	Appeared free from other sources of bias