The hypothesis of this work is that distraction is an effective way to modify the feeling and experience of chronic lumbar pain by modifying the functioning of the prefrontal cortex.

The main objective of this study is to show that during chronic low back pain generated during physical exercise, virtual reality distraction leads to the modification of the activity of the prefrontal cortex.

The secondary objectives are:

• Show a significant decrease in the average pain assessed with EVA during physical exercise with virtual reality distraction.
• Show an increase in the distance travelled with virtual reality distraction.
• Observe a decrease in perceived effort with virtual reality distraction.
• Quantify the adherence (presence) of subjects to the virtual environment

A pre-test phase at D0 will be carried out with the objective of individually determining the exercise conditions (speed and slope) of walking that will generate lumbar pain. Patients who have not experienced lumbar pain during this phase will be excluded from the study. The patients included are then randomized according to the order of physical exercise situations.

For the tests, patients will be equipped with a miniaturized wireless (Octamon, Artinis) and multi-channel (8 optodes) NIRS device placed on the patient's frontal lobe according to EEG 10-20 positioning (fig. 2). They will then be placed on an inclined treadmill according to the angle that caused the pain during the pre-test.

During the test, subjects will walk to the voluntary stop and the different reasons for the stop (feeling of fatigue, pain, etc.) will be recorded by visual analogue scales and questionnaires. The duration of the exercise will be measured by a digital stopwatch connected to the treadmill. During physical exercise, the bilateral activity of the prefrontal cortex will be recorded continuously at a sampling frequency of 10 Hz.

For each test, subjects will be confronted with 2 situations, on D1 and D2. In a situation, walking will be done without distraction. In the other situation, the patient will be placed in front of a screen with virtual reality simulation while performing the walking exercise.

Inclusion Criteria:

• The patient must have given free and informed consent and signed the consent
• The patient must be a member or beneficiary of a health insurance plan
• The patient is available for a 3-day follow-up
• The patient is between 18 and 75 years old
• Disabling lumbar pain beyond three months

Exclusion Criteria:

• Subject participates in another intervention study
• Subject is in an exclusion period determined by a previous study
• The subject is under the protection of justice, guardianship or curatorship
• Subject refuses to sign consent
• It is impossible to provide informed information about the subject
• The subject is unable to complete the study questionnaires
• The patient is pregnant, parturient, or breastfeeding
• The subject has a contraindication (or incompatible drug combination) for a treatment required for this study
• Recent involuntary weight loss
• Inflammatory schedule pain (predominantly nocturnal, requiring early morning rusting, improved by physical activity)
• Associated fever,
• Saddle anaesthesia
• Vesico-sphincterial disorders
• Typical root symptoms
• Systemic corticosteroid therapy
• History of cancer
• History of spinal trauma
• History of intravenous drug use
• Systemic corticosteroid therapy
• Surgical intervention of the spine or lower limbs
• Painful pathology of the lower limbs (coxarthrosis, gonarthrosis, vascular claudication or neurogenic when walking).

Exclusion criteria:

● Taking prescribed analgesic treatment after the inclusion procedure.