Mechanical hyperalgesia areas, also known as myofascial trigger points, are treated by manual therapy or invasive technics. Dry needling achieves an improvement of the symptomatology in 70% of the subjects, being the acute patients the most benefited. However, bruising, bleeding, pain during treatment or post-needling soreness. Plantar fasciitis is the most common cause of interior heel pain, affects approximately 10% of the general population and is one of the most benefited pathologies in the long term by the application of dry needling The gauge of the needle chosen for the treatment can influence post-needling soreness intensity and pressure pain threshold.

Objective To evaluate the relation between post-needling soreness intensity and needle diameter on the treatment of the most hyperalgesic point of the internal gastrocnemius.

Hypothesis Post-needling soreness intensity and pressure pain threshold depend on needle diameter applied in the treatment of the most hyperalgesic point of the internal gastrocnemius.

Intervention:

Two zones are established:

• Zone 1: where researcher nº 1 controls the data management and sample randomization.
• Zone 2: where researcher nº 2 locates the most hyperalgesic area and measures pressure point threshold variable and researcher nº 3 performs dry needling puncture.

Researcher nº 1 explains to the subjects how the study works, collects the confidential documents and scores the independent variables (sex, age and BMI). Every subject receives an identification code and is randomly assign to a intervention group (A, B or C) Researcher nº 2 makes delivery of the document where the variables pressure pain threshold and post-needling soreness intensity will be written down. Firstly, the visual analogue scale compliance prior to the intervention is requested. After that, the subject is placed in prone position on the stretcher with a slight knee flexion and the most hyperalgesic area in the internal gastrocnemius of the lower limb with plantar fasciitis is located and marked.

Researcher nº 2 performs the algometry at the most hyperalgesic area (3 measurements with 30 seconds between them), writes down the results of pressure pain threshold variable and leaves the room.

Researcher nº 3 receives a needle from researcher nº 1 ignoring its diameter (colour tab is removed). Firstly, contamination is prevented by disinfection, then, 10 insertions are made at the marked point (the number of local twitch response are counted) and the needle used is thrown in the sanitary waste container. Ischemic compression is performed for 60 seconds followed by an analytical stretch of the internal gastrocnemius for 30 seconds.

Once researcher nº 3 has finished the intervention leaves the room and researcher nº 2 returns to repeat the measurements (post-needling soreness intensity, by filling in VAS, and pressure pain threshold, performing algometry).

Researcher nº 2 reminds the subject to complete VAS at 12, 24, 48 and 72 hours (suggesting setting an alarm) and makes an appointment 48 hours after to perform the third measure of pressure pain threshold variable.

When all the data needed for the study has been collected, researcher nº1 gathers results and exports them for statistical interpretation.

Inclusion Criteria:

• Age: 18-65.
• Plantar Fasciitis diagnosis.
• Presence of hyperalgesic area in the internal gastrocnemius.

Exclusion Criteria:

• Belenophobia
• Hypothyroidism Presence of hyperalgesic area in the internal gastrocnemius - Diabetes
• Lymphedema o lymphatic surgery Muscle diseases
• Anticoagulant consumption Knee or ankle surgery
• Analgesic consumption during the study