Background Chronic musculoskeletal pain, especially chronic low back pain (CLBP), is the leading cause of disability worldwide, with a burden expected to rise due to aging and increased longevity. Despite strong evidence supporting multimodal and non-pharmacological management-particularly active physical therapy and self-management-clinical practice still shows low adherence to guidelines, with excessive reliance on imaging, rest, injections, and surgery.

Adherence to physical therapy remains one of the most significant barriers: only 40-50% of patients follow prescribed exercise programs. Factors include kinesiophobia, low motivation, and logistical obstacles. Mixed realities (XR: VR, AR, MR) offer solutions by enhancing motivation, reducing barriers, and personalizing rehabilitation. Evidence from systematic reviews shows VR-based rehabilitation can reduce pain, disability, and kinesiophobia, with immersive VR offering additional benefits like presence and habit-building.

The SHARESPACE project developed and tested a novel XR rehabilitation environment for CLBP that integrates immersive VR/AR, tele-rehabilitation, real-time motor tracking, avatars for social support, and cognitive architectures for synchronization. Usability studies with patients, clinicians, and the general population confirm its feasibility and acceptance. SHARESPACE has completed phases 1 and 2 of XR intervention development (design and feasibility), now aiming to move to phase 3: large-scale clinical validation.

Objectives The main goal is to evaluate not only short-term efficacy but long-term, as well as including more accurate and objective measures. A second objective is the commercial exploitation WE will valuate the efficacy, adherence, and cost-effectiveness of the SHARESPACE XR rehabilitation system compared to usual care in patients with CLBP.

Specific objectives include:

1. To conduct a two-site randomized controlled trial (RCT) comparing XR rehabilitation with conventional group rehabilitation.
2. To assess both short-term and long-term outcomes (pain intensity, disability, kinesiophobia).
3. To monitor and improve adherence through ecological momentary assessment and intervention (EMA/EMI) using an app and activity trackers.
4. To enhance motivation and engagement with gamification, social connectedness, and avatar-based interaction.
5. To generate evidence for commercial exploitation and integration into health systems.

Methodology

The project will conduct a two-site RCT with CLBP patients. Participants will be randomly allocated to:

• XR rehabilitation:

  • Two hospital sessions (traditional + XR-assisted training).
  • Four remote XR sessions with therapist and patients (L1 avatars).
  • Continued home-based XR with automated therapist avatars (L3) for up to 120 days.
  • Integration of EMA/EMI via an app and wearable devices to monitor daily activity, sleep, and adherence, with automated prompts to encourage compliance.

• Usual care: standard group rehabilitation sessions for 8 weeks.

Primary outcomes:

• Pain intensity (VAS, BPI).
• Disability (Oswestry Disability Index).
• Kinesiophobia (Tampa Scale of Kinesiophobia). Secondary outcomes: adherence rates, motivation, patient satisfaction, feasibility, and cost-effectiveness. Motor performance data will be captured in real time via XR tracking and transmitted to therapists for feedback.

Inclusion Criteria:

• Age range: Adults over 18 and under 70
• Diagnosis of chronic low back pain with or without radiculopathy
• Minimum of moderate disability (21% ODI score)
• Acceptance of participation and signed consent form
• Internet access at home

Exclusion Criteria:

• History of spinal surgery or fracture
• Signs of upper motor neuron injury: bilateral paresthesia, hyperreflexia, or spasticity, or other negative signs such as fractures
• Other severe medical or psychological conditions that prevent participation in the trial.