Return-to-Sport and Early Reinjury After Grade II Hamstring Injuries in Elite Professional Football Players
Abdullah Yener İnce, Muhammed Yusuf Afacan, Erkan ÖZYILMAZ, Tolgahan Korkmaz · Acibadem Universitesi Saglik Bilimleri Dergisi · 2026
Purpose: To evaluate return-to-sport duration and factors associated with delayed recovery and early reinjury in elite professional football players with Grade II hamstring injuries, with emphasis on the Munich muscle injury classification.
Methods: This retrospective observational cohort study included 42 elite professional football players treated for acute Grade II hamstring injury between 2016 and 2024. Injuries were subclassified according to the Munich classification as Type 3A or Type 3B. Demographic, anthropometric, injury-related, and sport-specific variables were recorded, including age, height, body weight, body mass index, injury side, playing position, and previous hamstring injury history. Returnto-sport time was defined as the number of days from diagnosis to unrestricted return to full team training and/or match availability. Reinjury was defined as a new hamstring injury in the same extremity within two months after return tosport. Nonparametric analyses were performed.
Results: Median return-to-sport time was 19 days, ranging from 11 to 54 days. Thirty-nine injuries were classified as Munich Type 3A and three as Type 3B. Type 3B injuries had significantly longer return-to-sport duration than Type 3A injuries, with median values of 30 and 18 days, respectively (p = 0.026). Return-to-sport time was not significantly associated with playing position, injury side, age, or body mass index. In the Type 3A subgroup, return-to-sport time was not associated with age, height, body weight, body mass index, or playing position. Reinjury occurred in three players. Players with reinjury had shorter initial return-to-sport duration than those without reinjury, with median values of 14 and 20 days, respectively (p = 0.026).
Conclusion: In elite professional football players with Grade II hamstring injuries, Munich classification subtype was associated with return-to-sport duration, whereas demographic, anthropometric, and position-related variables were not. Shorter return-to-sport duration was associated with early reinjury; however, because only three reinjury events were observed, this finding should be considered exploratory and should not be interpreted as evidence of causality. These
Findings: support MRI-based subclassification and criteria-based return-to-sport decision-making.