Forty semi-professional athletes with acute hamstring muscle complex injury type 3b were randomized to receive radial extracorporeal shock wave therapy (rESWT) plus a structured rehabilitation program or sham shock wave therapy plus the same rehabilitation program. Following post-randomization ultrasonographic re-evaluation, 4 patients were excluded due to reclassification of injury severity, resulting in a modified intention-to-treat population of 36 patients, with 18 patients per group. The primary outcome of interest was time to return to sport, defined using standardized clinical, functional, and strength-based criteria. Secondary outcomes included patient satisfaction at six months, re-injury rate within six months, and post-treatment isometric knee flexor strength. Outcomes were assessed from baseline through six months following trial inclusion. Overall, the results of the study revealed that the addition of rESWT significantly shortened time to return to sport compared with sham treatment, without increasing re-injury risk. It was also associated with preservation of post-treatment muscle strength in the previously injured limb. These findings suggest that rESWT provides a clinically meaningful adjunct to rehabilitation in acute structural hamstring injuries.