Comparison of some intrinsic risk factors of shoulder injury in three phases of menstrual cycle in collegiate female athletes

Abstract Objectives present study aims to investigate the changes in the shoulder joint stability factors during the menstrual cycle. Design cross-sectional study; Setting laboratory. Participants 15 healthy collegiate female athletes with normal menstrual cycles. Main outcome measures shoulder strength, proprioception, laxity and functional stability were the primary outcomes. Participants were assessed in three phases (mense, ovulation, midluteal (day 21) by 4 different categories of tests, each designed for a different factor. Shapiro-Wilk Test was used to determine normality of data, ANOVA and Friedman Test were used to compare results. Significance level and alpha were considered 95 percent and ≥0.05, respectively. Data shown a relation between proprioception, strength and menstrual cycle. Results shoulder strength was significantly increased in ovulation phase compared to other phases (p  0.14). Proprioception was significantly decreased in luteal phase than in mense and ovulation phases (p  0.14). Finally, ligament laxity and functional stability showed no change in all phases (p  Conclusion Menstrual cycle and sexual hormones affect muscle strength and proprioception of shoulder joint, but have no effect on ligament laxity and functional stability.