Purpose: This study aimed to cross-culturally adapt the second version of the Oslo Sports Trauma Research Center Questionnaires on Overuse Injuries (OSTRC-O2) and Health Problems (OSTRC-H2) into Greek. Materials and Methods: The questionnaires were translated using the back-translation method in accordance with international guidelines. The OSTRC-O2 was administered to 56 female volleyball players, focusing on shoulder injuries, while the OSTRC-H2 was delivered to 52 adolescent and young adult male and female volleyball and soccer players. Validity was assessed through content validity (Content Validity Index – CVI), face validity (using additional questions on comprehensibility, difficulty, relevance, and completeness), and concurrent validity (correlations between the OSTRC-O2 severity score and the numeric pain rating scale [NPRS], as well as between the OSTRC-H2 severity score with days of time loss [DL] and NPRS). Reliability was evaluated using internal consistency (Cronbach's α) and the test-retest method (intraclass correlation coefficient – ICC). The study was conducted for a two-week period and the test-retest was performed with a two-day interval. Results: Twenty-three athletes (41%) reported shoulder problems using the OSTRC-O2, while 28 injury events and 5 cases of illness were reported with the OSTRC-H2. Face and content validity were excellent (CVI = 0.925 and 0.975 for OSTRC-O2 and OSTRC-H2). A strong correlation was observed between the OSTRC-O2 severity score and the NPRS (ρ = 0.819, p < 0.001), while the OSTRC-H2 severity score demonstrated significant correlations with both the NPRS (ρ = 0.72, p < 0.001) and days of time loss (ρ = 0.625, p < 0.001). Both questionnaires demonstrated excellent reliability and internal consistency, with the OSTRC-O2 showing an ICC of 0.90 (95% CI: 0.82–0.94) and Cronbach's alpha of 0.84, and the OSTRC-H2 showing an ICC of 0.93 (95% CI: 0.89–0.97) and Cronbach's alpha of 0.93. Conclusions: The Greek versions of the OSTRC questionnaires are valid and reliable tools for injury surveillance among Greek volleyball and soccer players.Περισσότερα