Low back pain is one of the most common problems among adults and a leading cause of disability worldwide including in Saudi Arabia (Buchbinder et al., 2018) (Awaji, 2016) . Studies have shown that 80% of adults would experience low back pain at least once in their lifetime (Awaji, 2016). Research has shown that physical exercises are the most effective rehabilitation method. However, some CLBP patients have fear of movement and fear of increasing the pain (Alamam et al., 2019b), which will lead to inactivity and more disability. Moreover, low adherence to the prescribed exercise program is very common, which could be due to complexity of the program, boredom or lack of supervision and follow up(Elbur, 2015). VR fully-immersive -based exercise game can be used to enhance CLBP rehabilitation by keeping the patients engaged in the virtual environment distracting them from pain and stopping the cycle of fear of movement. Based on the previous problem our research questions are:

• Will the VR fully immersive based exercise game improve patient outcomes (fear, pain, reduce disability and improves physical function and adherence)? Aims of the Study.
• To assess the effectiveness of the VR fully immersive-based exercise game in the rehabilitation program for patients with CNSLBP with kinesiophobia, in reducing fear of movement, pain-related to disability, and improving physical function.

To assess the adherence of the VR-based exercise, which has entertainment aspect is better than adherence to the conventional paper-based exercise.

Significance of the Study. Based on the Fear-Avoidance model, the fear comes from the pain perception which increases level of disability (Leeuw et al., 2007). Thus, to break the fear cycle, we need first to reduce the pain intensity. This can be done by a virtual environment into a Head Mounted Displays (HMDs) that provides a fully immersive experience to engage the patients in a virtual environment and distract them from the pain while performing their exercises. Moreover, based on recent clinical guidelines for LBP rehabilitation, exercises are one of the most effective treatments for LBP. Therefore, we believe that a fully immersive based exercise game integrated with physical exercises that include a series of trunk movements such as moving forward, backward, sideways, and rotation. This solution will enhance the rehabilitation outcome since the patients who are suffering from CLBP with fear of movement and high level of disability can use the system at their home and train more for long period of time using a low-cost virtual reality device.

Inclusion Criteria:

1. Consented adult patients, male and female, aged 18 or older.
2. patient diagnosed with chronic non-specific low back pain (symptoms duration more than 3 month).
3. patient reported no health condition that would restrict movement or prevent safe participation
4. patient able to use smart phone.

Exclusion Criteria:

1. patients age more than 60 years. (As patient has high risk of morbidity could affect balance and movement)
2. Patients with spine surgery, hip arthroplasty, or spinal deformity like scoliosis.
3. Patient with red flags (e.g., active cancer, report recent or unexplained loss weight, infection, inflammation, or fracture)
4. Clinical neurological features like lumbar radiculopathy.
5. vestibular system dysfunction like vertigo or imbalance by using Head impulse test(Furman & Barton, 2015).
6. pregnancy.