Test of rising and sitting of the chair during 30 seconds as many times as possible.

BST. Biering-Sorensen test.The test is to keep the trunk in prone position as long as possible to assess the resistance of the trunk extensor musculature.

TSB. Test Side-Bridge assesses the resistance of the inclination muscles or lateral flexors of the trunk. In it the participants are placed in lateral recumbency on their dominant side in a mat. In this position, the participants support themselves with the elbow and the forearm of their dominant side and raise the pelvis until the trunk is aligned with the lower extremities. The test consists of maintaining the referred position as long as possible.

ITo. To assess the resistance of the flexor muscles of the trunk, the participants are placed supine with the hips and knees bent at 90º. The participants flex the upper part of the trunk until they touch the thighs with the elbows, keeping the cervical spine in a neutral position.

VAS. The analog visual pain scale is a tool that is used to assess the pain perceived by the patient in a valid and reliable way.

It is an instrument for measuring the intensity of pain that represents a horizontal line of 10 cm with a score of 0 to 10, where 0 represents non-pain and 10 unbearable pain.

The patient should place a vertical line on the horizontal line of the scale where he places his pain intensity.

HADS. This questionnaire allows to evaluate the psychosocial factors of the patient, through 14 questions with two subscales of 7 questions (one subscale on anxiety and the other on depression); The patient must answer one of the 4 items of each question without much reflection to have a real answer of how he was during the past week. The intensity or frequency of symptoms is evaluated with a Likert scale ranging from 0 to 3. In each subscale (anxiety and depression) the points are added and interpreted as such: 0-7 points: normal; 8-10 points: doubtful and higher than 11: clinical problem. This tool is validly and reliably used in clinical practice.

This questionnaire assesses the quality of life perceived by the patient. It is widely used in clinical practice and is approved as valid and reliable. There are 36 questions with 2,3,5 or 6 items in each question and with an assessment between 0 and 100. The questions assess physical function, function limitations due to physical health problems, body aches, general health, vitality, social functioning and emotional and mental health problems

The Semmes Weinstein monofilament test is a tool that evaluates tactile and pressure sensitivity in a valid and reliable way. A nylon filament attached to a handle is used which, when folded, applies a constant pressure of 10g. The investigator applies the monofilament perpendicular to the skin with increased pressure until the monofilament bends and without supporting it for more than 1 or 2 seconds.

The test will be performed on the sole of the foot in 4 points: the first toe, the base of the first, third and fifth metatarsals.

When the patient notices something, he puts a 1 and a 0 if he does not notice something. The sensitivity index is obtained with the sum of the values and is considered a sensitive patient only when it has a score of 8/8.