Introduction: the hamstring muscles has a great tendency to decrease its extensibility, originating a pathology with a own clinical entity, the Short Hamstring Syndrome (SHS), in addition to other problems on adjacent structures. All this present a great socioeconomic impact in the investigator's society. Various techniques have been demostrated to prduce an increase in flexibility, among which are the fascial techniques.

Objective: to evaluate the immediate efficacy of the treatment of the lumbar fascia in the flexibility of the hamstring musculature.

Methods: 41 women between 18 and 39 years old, in two groups. The experimental group received a technique of fascial stretching in the lumbar area while the control group participated in an off magnetotherapy machine. The hamstring flexibility in both lower limbs was measured by the Straight Leg Raising Test (SLR) and the Passive Popliteal Angle Test (PKE).

The hamstring muscles has a great tendency to decrease its extensibility, originating a pathology with a own clinical entity, the Short Hamstring Syndrome (SHS), in addition to other problems on adjacent structures. This study aims to help improve treatment for the problem mentioned before, which can be included within a therapeutic framework to combat SHS. In recent years, investigations have been carried out that include different techniques for stretching the hamstring muscles, as well as the treatment of other structures belonging to the posterior superficial chain. Within this last section, myofascial stretching techniques have been shown to be effective both in the short and medium term. Different techniques for stretching the hamstring muscles have been carried out with the aim of increasing the flexibility of the lower back in general.

he objective is to evaluate the immediate efficacy of the treatment of the lumbar fascia in the flexibility of the hamstring musculature.

The participants are 41 women between 18 and 39 years old, in two groups. The experimental group received a technique of fascial stretching in the lumbar area while the control group participated in an off magnetotherapy machine. The hamstring flexibility in both lower limbs was measured by the Straight Leg Raising Test (SLR) and the Passive Popliteal Angle Test (PKE).

Inclusion Criteria:

• Female between 18 and 39 years old.
• Signed informed consent

Exclusion Criteria:

• Any alteration that prevents the normal communication between the patient and the therapist at the time of the study.
• Have an injury in the hamstring muscles.
• Have a chronic or acute lumbar pain in the moment of the realization.
• Neurological or orthopedic desease.
• Any important estructural alteration in the lower members that may be likely to alter the results under study.