High rate of injuries detected during certain periods of menstrual cycle, raised the suggestion of hormonal impact on soft tissue and neuromuscular control with subsequent lost in joint stability, deterioration of postural balance and injury development. The aim of present study was to investigate possible differences in static postural balance during the preovulatory and postovulatory stages of menstrual cycle. Twenty one randomly selected eumenorrheic female university students accepted to participate in this study. Postural stability index (PSI) and sway distances were measured on a computer-based static stability force-platform with eyes open and eyes closed trials. Height, weight, waist and hip circumferences of the subjects were also measured. Evaluation of body fat percentage (BF) was made through biceps-triceps-subscapular-suprailiac skin-fold thickness measurements. Analysis of balance scores demonstrated better postovulatory comparing to preovulatory postural stability in terms of PSI (93.29 ± 4.26 versus 91.05 ± 6.21, p = 0.035), antero-posterior (0.99 ± 0.72 versus 0.77 ± 0.51 cm, p = 0.05) and medio-lateral (0.77 ± 0.64 versus 0.50 ± 0.42 cm, p = 0.04) sway distances. There was also statistically significant correlation between anthopometric and balance parameters with better postural balance in thinner participants. Our findings demonstrated that menstrual cycle does indeed influence postural stability, which also is the function of body composition in young females.

Key words: Postural balance, menstrual cycle, females, periods.