Achilles tendon is a frequent lower-limb tissue where tendinopathy may arise. Percutaneous Therapeutic Electrolysis (EPTE®) is an electronic device that enables to treat accurately, guided by an ultrasound, the tendon injured area by applying a galvanic current through an acupuncture needle. Thus, the first stage of physiological regenerative process may be obtained. Design: Randomized Controlled Clinical Trial. Objectives: To know the effectiveness of Percutaneous Therapeutic Electrolysis (EPTE®) versus a sham intervention at improving pain and function in patients who undergo Achilles Chronic Tendinopathy and to determine the efficiency of Percutaneous Therapeutic Electrolysis (EPTE®) with monopolar needle versus Percutaneous Therapeutic Electrolysis (EPTE®) with bipolar needle at improving pain and function in patients who undergo Achilles Chronic Tendinopathy. Participants: patients diagnosed with Achilles Chronic Tendinopathy. Setting. Infanta Leonor Hospital, Madrid, Spain. Experimental intervention: Percutaneous Therapeutic Electrolysis (EPTE®) with monopolar needle, 330 microamps, 1 min 20 sec versus bipolar needle. Sham intervention: the guide tube of the needle contacted with the skin and the device remained switched on to simulate its functioning.

Tendinopathy is a common injury among athletes, where the incidence reaches 50%. Nevertheless, industrial workers as well as sedentary subjects may also undergo this pain condition.

Achilles tendon is a frequent lower-limb tissue where tendinopathy may arise. Achilles tendinopathy risk factors have been detailed, such as: age, mechanical axis deviation of lower limbs, excessive training load dosage, and type of work activity. The middle portion of the tendon is the area where Achilles tendinopathy is most likely to be located. Interestingly, correlation between pain severity and the degree of tissue degeneration by imaging diagnosis is hardly showed in chronic tendinopathy conditions. Thus, chronic tendinopathy pain may be mediated not only by peripheral but by central mechanisms.

Percutaneous Therapeutic Electrolysis (EPTE® System; Manual EPTE, 2014 IONCLINICS & DEIONIC, S.L.) is an electronic device that enables to treat accurately, guided by an ultrasound, the tendon injured area by penetrating the skin with an acupuncture needle. A galvanic current goes through the device to the needle so that the first stage of physiological regenerative process may be obtained. That is due to a chemical reaction that leads to a controlled alkaline burn into the injured tissue and a subsequent basification of extracellular medium. That elicits an inflammatory response; the destroyed tissue is metabolized by phagocytosis process. Design: Randomized Controlled Clinical Trial. Objectives: To know the effectiveness of Percutaneous Therapeutic Electrolysis (EPTE®) versus a sham intervention at improving pain and function in patients who undergo Achilles Chronic Tendinopathy, and to determine the efficiency of Percutaneous Therapeutic Electrolysis (EPTE®) with monopolar needle versus Percutaneous Therapeutic Electrolysis (EPTE®) with bipolar needle at improving pain and function in patients who undergo Achilles Chronic Tendinopathy. Participants: patients diagnosed with Achilles Chronic Tendinopathy. Setting. Infanta Leonor Hospital, Madrid, Spain. Experimental intervention: Percutaneous Therapeutic Electrolysis (EPTE®) with monopolar needle, 330 microamps, 1 min 20 sec versus bipolar needle. Sham intervention: the guide tube of the needle contacted with the skin and the electrolysis device remained switched on to simulate its functioning.

Inclusion Criteria:

- Achilles Chronic Tendinopathy diagnosis (from 3months up to 3 years)

Exclusion Criteria:

• Physical therapy treatment within the last 4 months.
• Surgery approach for Achilles tendinopathy.
• Pregnancy
• Corticoid treatment in the last 4 months.
• Pacemaker
• Thrombophlebitis
• Systemic disease
• Cognitive disease
• Prosthesis or osteosynthesis
• Dermatopathies