Table 2 Description of the interventions used in the trial

MoodGYM

Setting Participants completed the MoodGYM program individually on their own personal computer at home

Purpose To provide psychological support via an internet-delivered cognitive behavioural approach

Materials Participants were directed to the MoodGYM website www.moodgym.com.au and asked to complete the five weekly modules. The modules explored thoughts, feelings, stressors and relationships that may contribute to psychosocial distress

Module 1 Feelings: Why you feel the way you do

Module 2 Thoughts: Changing the way we think

Module 3 Unwarping: Changing warped thoughts

Module 4 De-stressing: Knowing what makes you upset

Module 5 Relationships: Relationships and how they work out

Procedures One MoodGYM module was completed weekly. Fidelity was checked with a weekly telephone call by a research assistant. In circumstances that a participant reported not having completed a weekly MoodGYM module, a further phone call was made a few days later to ensure the module was completed. No additional counselling or psychological treatment advice was provided with these reminder telephone calls. The program was a self-led digital health technology with no contact with a health practitioner

Multimodal physical treatments

Setting Participants attended a private chiropractic or physiotherapy clinic. Physical treatments were provided by a registered chiropractor or physiotherapist with over 5 years of clinical experience. These practitioners were screened and inducted into the trial several months before the trial commenced

Purpose To provide practitioner-led multimodal physical treatments focused on reducing back pain and help participants to better self-manage their condition

Materials All participants received a pragmatic course of multimodal physical treatments, e.g., manual therapy (spinal manipulation or mobilisation and/or soft tissue massage) combined with reassurance, advice, education and general exercises. Reassurance that back pain would not worsen. Advice about symptom management and encouragement to remain active and avoid bed-rest. Education on activity pacing, lifting advice, computer ergonomic use and general injury prevention principles. Supportive exercises included general physical conditioning or home-based stretching and strengthening exercises relevant to the patient’s level of impairment and function. Treatment modalities that are not endorsed by clinical practice guidelines for the treatment of non-specific LBP were not offered to participants (e.g., therapeutic ultrasound, transcutaneous electrical nerve simulation, heat therapy, etc.). The selection of physical treatments was determined by the practitioner according to the presenting needs of the participant and according to clinical judgment

Procedures Participants received up to 12 treatments over a period of 8 weeks. The practitioner may have elected to use fewer treatments in cases where significant improvement was observed or if adverse events that warranted stopping care were experienced. Fidelity and treatment adherence were recorded by the treating practitioner at each visit