The influence of the menstrual cycle on muscle injuries - a systematic review and meta-analysis.

This systematic review and meta-analysis examined the relationship between menstrual cycle phases and the incidence of muscle injuries in female team sport athletes, following PRISMA 2020 and PERSiST guidelines. A comprehensive search was conducted in PubMed, Scopus, and SPORTDiscus from inception to mid-January 2024. Studies were included if they examined female team sport athletes of reproductive age with regular menstrual cycles and compared the occurrence of muscle injuries across at least two menstrual phases. Studies involving hormonal contraceptive use, medications affecting the menstrual cycle or musculoskeletal system, or menstrual dysfunction were excluded. Three studies met the inclusion criteria, involving 318 participants. Meta-analysis yielded a pooled Risk Ratio of 1.18 (95% CI: 0.75 to 1.86, p = 0.46) for injury risk between the luteal and follicular phases, suggesting no statistically significant association. However, the certainty of the cumulative evidence was rated as very low due to methodological limitations, including inconsistent phase classifications and reliance on imprecise methods for identifying menstrual phases. Consequently, no practical or clinical recommendations can be made at this time. Future research employing standardised, physiologically accurate methods for classifying and detecting menstrual cycle phases is necessary to better understand the potential links between hormonal fluctuations and injury risk.