Abstract Background In chronic conditions, such as back pain, the use of interventions that address physical, social and psychological aspects within a biopsychosocial framework are encouraged, however, applying this holistic multimodal approach in physical therapy practice (i.e., chiropractic and physiotherapy) is challenging. To explore the problem of delivering a biopsychosocially informed package of care in physical therapy practice a recent randomised control trial (RCT) called ‘Mind Your Back’ was conducted to evaluate the effectiveness of a combined physical and internet-delivered psychological intervention (psychologically informed physical treatments) compared to standard treatment for improving disability and self-efficacy in people with chronic LBP. The results of the trial indicated no difference between the two intervention groups. Although high-quality RCTs are considered gold standard for effectiveness of interventions, qualitative research methods embedded within a process evaluation framework are also used to reveal other issues and important information that help to explain clinical trial results, and to further the field of digital health interventions research. Therefore, within a process evaluation framework, the aim is to explore participants experiences of the interventions received throughout the Mind Your Back trial which led to a null result. Methods In-line with recommendations for a process evaluation this study used in-depth interviews and qualitative thematic analysis with participants of both arms of the trial 5–6 months after study completion. Semi-structured telephone interviews were conducted with twenty-five participants to explore their experiences of taking part in the Mind Your Back trial. Interviews were conducted in November 2017, transcribed verbatim and data analysed thematically. Results Two main themes were identified: (1) Personalised support and therapeutic alliance are important, and (2) MoodGYM lacked relevant, personalised and tailored support. Conclusion It is important to deliver tailored digital health supports that is personalised and fosters a therapeutic alliance.