Platelet-rich plasma (PRP) and extracorporeal shockwave therapy (ESWT) are both used for the treatment of soft tissue injuries in horses. Clinically, the question has been raised whether these two therapies could be used in combination. The hypothesis of this study was the application of ESWT to PRP would increase the release of platelet derived growth factors (PDGF) and transforming growth factors beta 1 (TGF) from platelets.