(1) Background: Myofascial pain syndrome (MPS) is a clinical condition characterized by localized non-inflammatory musculoskeletal pain caused by myofascial trigger points. Diathermy or Tecar therapy (TT) is a form of noninvasive electro-thermal therapy classified as deep thermotherapy based on the application of electric currents. This technique is characterized by immediate effects, and its being used by high performance athletes. (2) Methods: A total of thirty-two participants were included in the study who were professional basketball players. There was a 15-person Control Group and a 17-person Intervention Group. TT was applied in the Intervention Group, while TT with the device switched off (SHAM) was applied in the Control Group. The effects were evaluated through the Lunge test, infrared thermography, and pressure threshold algometry at baseline, 15, and 30 min after the intervention. (3) Results: the Intervention Group exhibited a greater increase in absolute temperature (F[1,62] = 4.60, p = 0.040, η2p = 0.13) compared to the Control Group. There were no differences between the groups in the Lunge Test (F[1.68,53.64] = 2.91, p = 0.072, η2p = 0.08) or in pressure algometry (visual analog scale, VAS) (F[3.90] = 0.73, p = 0.539, η2p = 0.02). No significant short-term significant differences were found in the rest of the variables. (4) Conclusions: Diathermy can induce changes in the absolute temperature of the medial gastrocnemius muscle.
Keywords: basketball; diathermy; gastrocnemius muscle; range of motion; sport injuries; thermography; trigger point.