The goal of this clinical trial is to evaluate whether a wearable biofeedback smartbelt system can improve pain and disability in adults with chronic lower back pain. The intervention combines a wearable belt that measures muscle activity with a mobile application that provides real-time feedback during exercise.

The main questions it aims to answer are:

• Does the MMG-biofeedback system improve disability, as measured by the Oswestry Disability Index (ODI), compared to standard care alone over an 8-week period?
• Does the system reduce perceived pain levels and improve exercise adherence in individuals with lower back pain over an 8-week period?

Researchers will compare participants receiving the MMG-biofeedback belt alongside standard care to those receiving standard care alone to determine whether the addition of real-time muscle activation feedback leads to improved outcomes.

Participants will:

• Be randomly assigned to either the intervention group (biofeedback system + standard care) or control group (standard care only)
• Complete an 8-week home-based exercise programme, all participants are asked to complete the programme at least 5 times a week
• Use the wearable belt and mobile application during exercise sessions (intervention group only)
• Receive a booklet with the exercise programme and video links (control group only)
• Complete questionnaires on pain, disability, and usability at baseline and after 8 weeks, and at a 3-month follow-up
• Have their exercise adherence and engagement monitored throughout the study

The study includes an initial pilot phase to assess feasibility, followed by a larger randomised controlled phase to evaluate early clinical effectiveness.

BACKGROUND

Lower back pain is the leading cause of chronic disability in the UK and entails direct treatment costs to the NHS of >£1.5 billion p.a. Evidence-based guidelines recommend back exercises and/or physiotherapy as the principle treatment. However, since long-term, intensive physiotherapy is unrealistic on the NHS given limited resources, professional bodies increasingly advocate self-management.

While self-led back exercise may be cost-efficient, its effectiveness is diminished by poor patient motivation and compliance. The current standard of care: a short course of training by a physiotherapist, followed by provision of a visual guide, are met with exercise adherence rates as low as 30%. This results in persistent pain, depression, unemployment and analgesic dependency.

The approach we shall take is to devise a practical sensor-feedback system that can detect appropriate back exercises, thereby encouraging self-motivation and automated supervision of exercise. The system is unique in using a patented sensor system - mechanomyography (MMG) - that wirelessly measures trunk and limb muscle contraction (in addition to movement), which is key to assessing core-strengthening exercises.

Our team have pioneered clinical applications of wearable mechanomyography (MMG) for purposes such as: remote assessment and exercises in stroke, and foetal movement detection via maternal abdomen. In one study, MMGs worn on stroke patients' arms predicted expert 3-class classifications of arm function with accuracies of up to 80%. Our ability to detect muscular contraction with MMG, rather than joint movement, will be important for monitoring back exercises since many of these involve isometric trunk muscle contraction, i.e. without spinal or limb movements.

RATIONALE FOR CURRENT STUDY

Lower back pain (LBP) is a leading cause of disability worldwide. Although exercise-based rehabilitation is recommended as a first-line treatment, adherence to prescribed exercises is often poor, and many patients struggle to activate key stabilising muscles effectively. The MMG-biofeedback belt has been developed to address these limitations by providing real-time feedback on core muscle activation, with the aim of improving exercise quality, motivation, and consistency.

Meaningful improvements in disability over an 8-week period have been demonstrated in previous rehabilitation studies, including a large cohort showing clinically significant reductions in Oswestry Disability Index (ODI) scores following standard physiotherapy programmes. Research also shows a clear dose-response relationship between exercise frequency and improvements in pain and disability, with greater adherence producing substantially larger effects. The MMG-biofeedback system is specifically designed to support this behavioural change by increasing engagement and encouraging regular, correctly performed exercises during unsupervised home practice.

Our proof-of-concept work has already shown that biofeedback substantially increases trunk muscle activation and self-initiated exercise behaviour, and these effects are expected to improve further with the enhanced design of the belt and app. Together, this evidence indicates that the MMG-biofeedback belt has strong potential to improve exercise adherence, muscle engagement, and clinical outcomes. A structured Phase 1/2 trial is therefore warranted to assess the early clinical effectiveness before progressing to a Phase 3 trial on a larger, multi-centre cohort.

STUDY OBJECTIVES

Primary Objective

1. To determine the clinical effectiveness of the MMG-biofeedback system in improving disability and pain in patients with LBP when used alongside standard care, as compared to standard care alone over an 8-week period.

   Secondary Objectives

2. To assess feasibility metrics, including recruitment and retention, usability, data completeness, adherence, and device safety.

3. To evaluate user perspectives regarding motivation, comfort, usability, and perceived value of the belt and app.

STUDY DESIGN

This study is a two-stage, parallel-group randomised controlled trial designed to evaluate the early clinical effectiveness of the MMG-biofeedback belt system for individuals with chronic lower back pain (LBP). All participants will have LBP and will be randomised to either the intervention group, receiving the MMG-biofeedback belt and mobile application alongside standard care; or the control group, which will receive standard care alone. All participants will complete an eight-week intervention period with assessments at baseline and immediately after the programme.

The first stage of the study is an internal pilot involving the first 40 participants recruited. These participants will be randomised using a provisional allocation ratio of 1:1 (intervention: control) and will complete all study procedures. The purpose of the pilot is to determine the feasibility of recruitment and retention, evaluate MMG signal quality and completeness, assess adherence to prescribed home exercises, and confirm the safety and practicality of the protocol. Progression to the full trial will be dependent on predefined feasibility criteria, including acceptable signal quality, adequate adherence, absence of unexpected safety concerns, and satisfactory usability ratings.

Based on the findings of this pilot stage, the final randomisation ratio for the main trial (Phase 2) will be selected. This may remain at 1:1 or may shift to 2:1 if this is deemed to provide a more appropriate balance between statistical power, feasibility, and resource considerations. This adaptive decision will be made before the commencement of Phase 2 and will not affect the pilot data, which will be retained in all final analyses.

The second stage of the study is the early-effectiveness RCT, in which a further 40 participants with LBP will be recruited, bringing the total sample to 80 participants. These participants will be randomised using the final allocation ratio determined from the pilot stage and will follow the same intervention and assessment procedures as those in the pilot. The purpose of Phase 2 is to evaluate the early clinical effectiveness of the MMG-biofeedback belt in addition to standard care and to estimate effect sizes and variability necessary for planning a Phase 3 trial. This stage will also enable a broader assessment of usability, adherence and device performance across a larger and more diverse participant sample.

Inclusion Criteria:

1. Over the age of 18
2. Non-specific LBP for at least 6 weeks in the past 12 months
3. Pain 4/10 on a visual analogue scale or more or Oswestry Disability Index over 20%

Exclusion Criteria:

1. Serious spinal pathology ("red flags") such as:

   • History of malignancy with new onset back pain suggestive of recurrence.
   • Unexplained weight loss, fever, or systemic symptoms.
   • Recent significant trauma (e.g., fall from height, road traffic accident).
   • Suspected or confirmed spinal infection (e.g., discitis, osteomyelitis).
   • Cauda equina symptoms, including urinary retention/incontinence or saddle anaesthesia.
   • Progressive neurological deficit (e.g., worsening weakness, loss of reflexes).

2. Recent spinal surgery or invasive spinal procedures within the past 3 months.

3. Severe cardiovascular or respiratory disease that prevents safe participation in mild to moderate exercise (e.g., unstable angina, uncontrolled heart failure).

4. Pregnant women or those less than three months postpartum.

5. Known allergy to materials used in the belt (e.g., Lycra or related fabrics).

6. Cognitive impairment that prevents informed consent or ability to follow exercise instructions.

7. Concurrent participation in another intervention trial that may interfere with the study outcomes.

De-identified individual participant data (IPD) underlying the results reported in publications will be made available to other researchers upon reasonable request. This will include participant-level data for primary and secondary outcomes (e.g. disability scores, pain scores, adherence metrics), along with relevant baseline characteristics.

Raw sensor data (e.g. MMG signals) and proprietary algorithms will not be shared in full due to intellectual property considerations. However, processed or aggregated data derived from these signals may be shared where appropriate to support reproducibility of findings.

All shared data will be fully anonymised in accordance with GDPR and institutional data protection policies.

De-identified individual participant data (IPD) and supporting documents will be made available following publication of the primary study results. Data will be accessible for up to 5 years after publication. Supporting documents, including the study protocol and statistical analysis plan, may be made available earlier where appropriate.

Access to de-identified IPD and supporting information will be granted to qualified researchers who provide a methodologically sound research proposal. Requests will be reviewed by the study team and subject to approval. Data will be shared under a data sharing agreement to ensure appropriate use and protection of participant confidentiality.

Data will be provided in a secure, anonymised format. Proprietary data, including raw sensor signals and algorithms, will not be shared; however, processed or aggregated data sufficient to reproduce study findings may be made available upon request.