Action Mechanisms of Shock Waves on Pain

The aim of this study is to evaluate whether the intensity of pain perceived during the application of extracorporeal shockwave therapy (ESWT) is determinant for producing changes in pressure pain threshold (PPT) in asymptomatic subjects. The investigators will perform a single controlled random trial to three groups. Two of them will receive ESWT whereas the third group will get a cold pressure test (CPT).