Paungmali 2017.

Study characteristics
Methods	Study design: RCT (cross‐over) Setting: Thailand, healthcare Exercise groups: 1 Comparison groups: 2
Participants	Number of participants: 75 (E1 = 25, C1 = 25, C2 = 25) Chronic LBP duration: 40.36 months (long) Neurological/radicular symptoms: No participants Mean age (years): 33 Sex (female): 72%
Interventions	Exercise Group 1 (E1): Lumbo‐pelvic core stabilisation exercises: exercises performed in supine position, focussing on exercising the abdominal and trunk muscles facilitated by the Pilates power gym transformer machine; type = core strengthening; duration = 0 weeks; dose = low; design = partially individualised; delivery = individual; additional intervention = none Comparison Group 1 (C1): Usual care/no treatment (control: participants lie in supine position, with legs passively angled the same way as the active intervention group) Comparison Group 2 (C2): Placebo: automated passive cycling (moves participants legs passively in the same manner as the active intervention, without engaging core muscles)
Outcomes	Core outcomes reported: Pain (Visual Analogue Scale) Follow‐up time periods available for syntheses: 0 weeks (short)
Notes	Conflicts of interest: None to declare Funding source: TRF & MUA Other: Information modified for author contact; sufficient data not available for inclusion in meta‐analyses
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Patients were randomised to order of exercises; no description on the randomisation process
Allocation concealment (selection bias)	High risk	No description of randomisation process to judge treatment allocation
Blinding of participants and personnel (performance bias) All outcomes	Low risk	1. Patients could not be blinded to their intervention due to the nature of the interventions; 2. Lack of patient blinding likely did not lead to deviations from intended intervention, as all patients were aware that they would have the chance to participate in all three study interventions.
Blinding of care provider (performance bias)	Low risk	1. Care providers could not be blinded due to the nature of the interventions; 2. Unlikely that lack of care provider blinding led to deviations from intended intervention, as all patients would have the chance to participate in all three study interventions.
Blinding of outcome assessment (detection bias) All outcomes	High risk	1. For the outcome of interest (pain), the outcome assessors were the participants themselves, who could not be blinded due to the nature of the interventions; 2. Pain and function are subjective and are susceptible to awareness of the intervention; 3. Outcomes in a control versus exercise study likely to be altered by awareness of intervention.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1. No description of dropout rate; 2. Analyses would exclude missing; 3. Increased pain and decreased function could cause missing outcome; 4. No information on missing data; 5. No information
Participants analysed in group allocated (attrition bias)	Low risk	1. Participants were analysed according to each intervention they received (complicated by cross‐over design, but no cause for concern over risk of bias).
Selective reporting (reporting bias)	Low risk	1. All analyses were conducted and reported as described in methods.
Groups similar at baseline (selection bias)	Low risk	Same 25 participants were in all three intervention "groups" due to cross‐over study design; baseline characteristics of all three "groups" were identical.
Co‐interventions avoided or similar (performance bias)	Low risk	Subjects were advised to refrain from medications, alcohol, and heavy physical activities for at least 8 hours prior to the test.
Compliance acceptable in all groups (performance bias)	Low risk	No information on compliance
Timing of outcome assessment similar in all groups (detection bias)	Low risk	1. For all participants, outcome assessments were performed at the same time points after each intervention, and using the same measurement tools (within each outcome); 2. Visual Analogue Scale (for pain) is a well‐validated tool in the context of low back pain.
Other bias	Low risk	Risk of insufficient wash‐out period between interventions; partially addressed by randomising the order in which patients participated in the three interventions