Increased Postural Sway and Changes in the Neuromuscular Activities of the Ankle Stabilizing Muscles at Ovulation in Healthy Young Women

Abstract

Lateral ankle sprains are one of the most common injuries among the physically active subjects. Ankle inversion-eversion laxity is greater and dynamic postural control is less in women compared with men. The purpose of this study was to examine differences in postural sway and its effects on the neuromuscular activities of the ankle stabilizing muscles during the menstrual cycle in young women. Fourteen young women with regular menstrual cycles participated in this experiment. Postural sway and electromyographic signals of the lateral gastrocnemius, peroneus longus (PL), and tibialis anterior (TA) were recorded while the participants performed eight different balance tasks at ovulation and early follicular phase during one full menstrual cycle. Significantly greater postural sway in the two most difficult balance tasks was observed at ovulation compared to that in the early follicular phase (p < 0.001). A similar pattern was also observed in terms of PL activity, while TA activity was significantly greater in the most difficult balance task at ovulation. In addition, TA-PL co-contraction (TA/PL ratio) was significantly higher at ovulation compared with that in the follicular phase in the two most difficult balance tasks (p < 0.01). Young women could benefit from increased understanding of the varying neuromuscular activation patterns throughout the menstrual cycle. The results of this study suggest that health professionals should be aware of the physiological effects and the shifts in neuromuscular strategies in each menstrual cycle phase in order to prevent increased risk of lower extremity injury.

Rutumati Lakshanas-Estrus Signaling In Humans

“…This would support the previous evidence pointing to a greater reduction in balance ability and tremor during ovulation period. A previous study also showed greater ankle laxity at ovulation than in other phases of the menstrual cycle [19]. All these evidence indicates that, there is general muscle, ligament laxity during the period of ovulation which supports the physiological change during rutu kala, 'Srasta kukshi, akshi moordhajaam'.…”

“…As estrogen levels peak during the ovulatory phase, significant increase in knee laxity have been detected. Various studies have investigated the effect of menstrual cycle on laxity of the ligaments and knee stabilizing muscles such as quadriceps and hamstring [19].…”

Correlation between Mechanical Properties of the Ankle Muscles and Postural Sway during the Menstrual Cycle

“…A recent study found that there was significantly greater postural sway during ovulation than during the follicular phase of the menstrual cycle Lee and Yim 2016). When women had a reduced capacity to control postural sway during ovulation, neuromuscular control of balance relied more on the TA than was seen during the follicular phase to compensate for ankle laxity.…”

“…The GPower 3.1 software (Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany) was used to calculate the sample size needed using a moderate effect size of 0.85 between the two different menstrual cycle phases, with an alpha error probability of 0.05 and a power of 0.85 Lee and Yim 2016). A sample size of 15 participants was required to provide a statistical power of 86.4%.…”

“…Similarly, reductions in muscle tone also can increase instability in balance. Laxity in tendons and ligaments has also been shown to affect stability Lee and Yim 2016).…”