The effects of the menstrual cycle on the static balance in healthy young women.

[Purpose] The purpose of this study was to investigate the effects of the menstrual cycle on the static balance of healthy young women. [Subjects and Methods] Eighteen healthy young subjects (mean age 19.1 years; weight 57.5 kg; height 159.9 cm) participated in this study. The Good Balance system was used to measure the postural sway speed and velocity moment of subjects in the static standing posture. Subjects were measured for static balance between 1 and 3 days after menstruation and 13 days after menstruation. [Results] The velocity moment of postural sway was significantly higher at 13 days after menstruation. [Conclusion] Our results indicate that the menstrual cycle affects the static balance of healthy subjects. During the menstrual cycle, intensity for balance exercises in females should be carefully controlled for injury prevention.