Sherman 2005.

Study characteristics
Methods	Randomized controlled parallel‐group trial.
Participants	101 participants with chronic non‐specific LBP. Setting: trial run through an integrated healthcare system. Yoga classes held at health system facilities (number of facilities not stated). Country: USA. Recruitment: invitations describing study sent by researchers to people with primary care provider visits between 3 and 15 months before the study for treatment of back pain. Self‐referral through advertisements in a health plan consumer magazine. Inclusion criteria: men and women aged 20–64 years with recent primary care visit for LBP. Exclusion criteria: back pain that was complicated (e.g. sciatica); potentially attributable to underlying disease or conditions (e.g. pregnancy); minimal (rating < 3 on a 'bothersomeness' scale of 0 to 10); had been treated with yoga or exercise in past year; currently treated with other interventions; possible disincentive to improve (e.g. were receiving worker's compensation); had severe or unstable medical or psychiatric conditions or dementia; had contraindications to the intervention (e.g. symptoms consistent with severe disk disease), unable to participate in classes or unwilling to practice at home; unable to speak or understand English. Duration and follow‐up: interventions provided for 12 weeks with additional follow‐up at 26 weeks.
Interventions	Yoga group: (n = 36) 12 weekly 75‐min viniyoga classes, each with a specific focus: (quotes) "relaxation; strength building, flexibility, and large‐muscle movement; asymmetric poses; strengthening the hip muscles; lateral bending; integration; and customizing a personal practice." "[A]ll the sessions emphasized use of postures and breathing for managing low back symptoms…" "[P]ostures were selected from a core of 17 relatively simple postures…" "Each class included a question‐and‐answer period, an initial and final breathing exercise, 5–12 postures, and a guided deep relaxation." Home practice: daily home practice encouraged and yoga participants received CDs to guide them through the postures with the appropriate mental focus. Exercise group: (n = 35) 12 weekly 75‐min exercise classes. Intervention designed by a physiotherapist and was likely different from previous physiotherapy. Exercise sessions began with an educational talk, then simple warm‐ups and a series of 7 aerobic exercises and 10 strengthening exercises, ending with stretching exercises and a short, unguided period of deep breathing. Home practice: encouraged and exercise participants received a handout to assist them. Self‐care group: (n = 30) a copy of an evidence‐based book of self‐care strategies was mailed to participants (Moore 1999). Common interventions: all participants continued to have access to all medical care provided by their insurance plan. Co‐interventions: no specific mention of allowed or restricted co‐interventions.
Outcomes	Back‐specific function (RMDQ) at 6, 12, and 26 weeks. Other outcomes collected: bothersomeness of pain during the previous week (0 = 'not at all bothersome' and 10 = 'extremely bothersome'); SF‐36 Mental Health component (not reported in results); SF‐36 Physical Health component (not reported in results); changes in medication use at 6 and 12 months.
Notes	Adverse events: no serious adverse events reported. 1 participant discontinued yoga classes because postures that required her to move her head below her heart precipitated her migraine headaches. 1 participant in exercise class strained her back during class and sought care from a chiropractor. Measurement of expectations or treatment preferences at baseline: participants were asked to describe their current pain and to rate their expectations for each intervention. Table 1 of the publication showed median expectation of helpfulness for each treatment in each group: median of 8 for exercise and yoga in both the exercise and yoga groups, median of 8.5 for exercise and 9 for yoga in the self‐care group, and median of 4 or 5 for self‐care in each intervention group. Preferred treatment was exercise for 26–33%, yoga for 27–44%, and other for 28–40%. Reported similar expectations of helpfulness from yoga or exercise but had lower expectations for the book. Unpublished data: Dr Karen Sherman e‐mailed LSW on 23 November 2015 that she did not have group means and standard deviations available from her trial. Funding: US National Institutes of Health (NIH). Quote: "Grant Support: By the National Center for Complementary and Alternative Medicine (grant R21AT 001215) and the National Institute for Arthritis and Musculoskeletal and Skin Diseases (grant P60AR48093). Potential Financial Conflicts of Interest: None disclosed."
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Used computer‐generated random assignments.
Allocation concealment (selection bias)	Low risk	A researcher not involved in participant recruitment or randomization placed assignments in opaque sequentially numbered envelopes.
Blinding of participants	High risk	No blinding as control interventions were conventional exercise or self‐care book; outcomes based on self‐assessment.
Blinding of personnel/providers	High risk	No blinding.
Blinding of outcome assessors	High risk	Quote: "Interviewers who were masked to the treatment assignments conducted telephone interviews at baseline and at 6, 12, and 26 weeks after randomization." Comment: however, participants were not blinded and self‐reported the outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Very low attrition rates (total 6% at 26 weeks) although there was no description of how missing data were managed.
Selective reporting (reporting bias)	Unclear risk	Clinical outcomes reported as per description on ClinicalTrials.gov, where there was not a formal statement of primary and secondary outcomes but a statement that the trial will report (quote) "symptoms, function, quality of life, and utilization and costs of back pain related care." However, utilization and costs were not mentioned in the study report.
Group similarity at baseline	Low risk	Groups matched on most important indicators.
Co‐interventions	Low risk	Use of non‐study treatments matched initially and reduced in yoga group compared with control groups.
Compliance	Low risk	36/36 yoga participants attended ≥ 1 class and the median number attended was 9 out of a possible 12. For exercise, 33/35 participants attended ≥ 1 class and the median number attended was 8. Class attendance was similar for yoga and exercise groups.
ITT analysis	Low risk	All randomized participants were stated to be analyzed in the group to which they were randomized.
Timing of outcome assessments	Low risk	Outcome assessment at set time points.
Other bias	Low risk	No other biases identified.