One of the treatment modalities currently available in this hospital to treat this type of patients with low back pain who present with chronic pain are the group sessions that are carried out to provide information to the patient about the anatomy, biomechanics and ergonomics and are complemented with sessions of physical exercise. Based on the latest publications on treatment of this type of patients, The investigators have seen that this intervention is insufficient, and that it could be improved by combining education based on Pain Neuroscience Education (PNE)).

The present study proposes implementing this program to a randomly assigned group of patients participating in the group sessions aimed at patients with lumbar pain called "Back-pain Protocol" that are currently relized in the Physiotherapy Area of a hospital; and compare the results of this intervention with those obtained in another group that will only carry out the sessions with the traditional method that is currently used.

Procedure The physiotherapist in charge of the chronic back pain programme group ("back pain protocol") is contacted. The study will be explained and the materials and training to deliver the PNE session will be provided.

Participants who meet the inclusion criteria will then be identified and randomised to the intervention or control group.

At the end of the first session, which currently takes place in group chronic back pain treatment programmes, the physiotherapist will explain the study and ask for cooperation. The information sheet is handed out. Those who decide to participate will receive an informed consent form and some questionnaires to fill in: the Numeric Pain Rating Scale (NPRS) to assess their level of pain, the Central Sensitisation Inventory, the Pain Catastrophic Scale (Spanish version), the Tampa Kinesiofobia Scale (TSK).

Interventions The current protocol consists of five sessions spread over one and a half months. Patients come to the rehabilitation classroom in two groups of 10 people per day for one hour.

The first session consists of an informative talk. The physiotherapist gives information and explanations about the "back pain protocol". The physiotherapist explains the problems of posture and gestures that can be beneficial or detrimental to their treatment, their daily activities, their work and their sporting activities.

In the second, third and fourth sessions, the participants learn specific exercises for back pain. Patients receive a booklet with the exercises and postures to be incorporated into their daily habits.

Treatment. This study proposes that only participants assigned to the intervention group will also receive an additional patient education session on Pain Neuroscience Education (PNE).

This session will last one hour and will be given in an additional session the day after the first information session of the current protocol. They will also be given information to read and review at home. Only patients randomised to the intervention group will attend this session.

The aim of this intervention is to provide participants with information in a clear and simple way, so that they can change their attitude to pain, inviting them to take a more active and less contemplative role. The physiotherapist will explain to the participants in a simple way that chronic pain is not always the result of tissue damage. Neuroscience has shown that it is possible to have persistent pain without tissue damage or with damage that justifies the perception of disproportionate pain. The physiotherapist will also explain the difference between acute and chronic pain, central sensitisation processes (CS) and endogenous pain control mechanisms. The physiotherapist will talk about how thoughts, beliefs and emotions modify the painful experience and how the erroneous information received, sometimes iatrogenic, modifies the mechanisms of pain processing. The content of the neuroscience education lectures is based on the book Explain Pain.

Inclusion Criteria:

• Patients participating in the "back protocol" groups in the hospital
• That present pain of more than 3 months of evolution

Exclusion Criteria:

• Oncological pain
• Fracture or spinal surgery in the last year
• Cognitive neurological alteration that prevents understanding the contents of the session
• Alterations at the motor level that prevent the realization of the program of directed physical exercise that is currently carried out
• Pregnancy
• Urinary or intestinal incontinence
• Other clinical conditions that may aggravate chronic spinal pain (chronic fatigue syndrome, fibromyalgia and complex regional pain syndrome)

Participants receive TEN sessions, but do not know that one of the groups will receive extra information