Electrolysis Percutaneous Therapeutic (EPTE) consists of the application of a galvanic electrical current with an acupuncture needle in the soft tissue, in this case the supraspinatus tendon, to initiate a local inflammatory process allowing phagocytosis and repair of the affected tissue. The technique is pain-free since the electrical intensity is adapted to each patient. In addition, patients will be asked to perform an eccentric loading exercise program for the shoulder musculature, particularly the supraspinatus and infraspinatus muscles, to be performed on an individual basis twice every day. The therapeutic protocol will be applied for 4 weeks.

Patients will be asked to perform an eccentric loading exercise program for the shoulder musculature, particularly the supraspinatus and infraspinatus muscles, to be performed on an individual basis twice every day. The therapeutic protocol will be applied for 4 weeks.

A 10-point Numerical Pain Rating Scale (NPRS; 0: no pain, 10: maximum pain) will be used to assess the patients' current level of shoulder pain, and the worst and lowest level of pain experienced in the preceding week in the shoulder area.

The Disabilities of the Arm, Shoulder and Hand (DASH) will be used to determine the disability induced by shoulder pain