Background: There is a hypothesis in literature that the mechanical action of deep transverse friction massage (DTF) produces vasodilatation and increases blood flow. But as yet, no experimental study has confirmed the effect of DTF on blood flow in the Achilles tendon. Objective: The purpose of the present study was to investigate whether one session of DTF can influence the Achilles tendon blood flow.

Design: a randomized pre- posttest trial was set up. Patients: Sixty-two healthy participants volunteered. Each person underwent the following four steps of the procedure: 1. Measuring the tendon blood flow (PRE), 2.fifteen minutes of DTF on the Achilles tendon, 3. Measuring of the tendon blood flow (POST), 4.follow - up measurement after 20 minutes of rest (POST20).

Intervention: one leg of each person was randomly assigned to deep transverse friction session, the other leg was used as a control leg. Friction was applied continuously for a total of 15 minutes. Measurements: the microcirculation was determined at 2 and 8 tissue depths at the distal and the proximal midportion of the Achilles tendon. For each level, the capillary blood flow, the tissue oxygen saturation, and the postcapillary venous filling pressure was registered.

Exclusion Criteria:

• a history of lower leg injury
• systematic disease
• persons using drugs
• subjects with circulatory disorders or cardiovascular diseases