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

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 < 0.5) (effect size >0.14). Proprioception was significantly decreased in luteal phase than in mense and ovulation phases (p < 0.5) (effect size >0.14). Finally, ligament laxity and functional stability showed no change in all phases (p < 0.5).

Conclusion: Menstrual cycle and sexual hormones affect muscle strength and proprioception of shoulder joint, but have no effect on ligament laxity and functional stability.