Sex differences, hormone fluctuations, ankle stability, and dynamic postural control.

CONTEXT: Hormonal fluctuation as a risk factor in anterior cruciate ligament injury has been investigated with conflicting results. However, the influence of hormone fluctuations on ankle laxity and function has not been thoroughly examined.

OBJECTIVE

To examine the potential hormone contributions to ankle laxity and dynamic postural control during the preovulatory and postovulatory phases of the menstrual cycle using an ankle arthrometer and the Star Excursion Balance Test in healthy women. The cohort group consisted of male control participants.

DESIGN

Cohort study.

SETTING

Research laboratory.

PATIENTS OR OTHER

PARTICIPANTS

Twenty healthy women (age = 23.8 ± 6.50 years, height = 163.88 ± 8.28 cm, mass = 63.08 ± 12.38 kg) and 20 healthy men (age = 23.90 ± 4.15 years, height = 177.07 ± 7.60 cm, mass = 80.57 ± 12.20 kg).

INTERVENTION(S): Ankle stability was assessed with anterior-posterior and inversion-eversion loading. Dynamic postural control was assessed with the posteromedial reaching distance of the Star Excursion Balance Test.

MAIN OUTCOME MEASURE(S): Female participants used ovulation kits for 3 months to determine the time of ovulation; during their preovulatory and postovulatory phases, they were tested in the laboratory with an ankle arthrometer and the Star Excursion Balance Test. Male participants were tested on similar dates as controls. For each dependent variable, a time by side by sex repeated-measures analysis of variance was performed. Statistical significance was set a priori at P < .05.

RESULTS

For anterior-posterior laxity, a side main effect was noted (F₁,₃₈ = 10.93, P = .002). For inversion-eversion laxity, a sex main effect was seen (F₁,₃₈ = 10.75, P = .002). For the posteromedial reaching task, a sex main effect was demonstrated (F₁,₃₈ = 8.72, P = .005). No influences of time on the dependent variables were evident.

CONCLUSIONS

Although women presented with more ankle inversion-eversion laxity and less dynamic postural control, hormonal fluctuations during the menstrual cycle (preovulatory compared with postovulatory) did not affect ankle laxity or dynamic postural control, 2 factors that are associated with ankle instability.