Ankle Laxity Fluctuation and Sex Hormones in Women With/Without Recurrent Sprains

Incidence of ankle sprain and chronic ankle instability is higher in women versus men. One sex-specific factor may be the greater ligamentous laxity in women compared with men, potentially influenced by estrogen and relaxin activity. This study aimed to investigate changes in ankle joint laxity and its association with hormone levels in women with and without recurrent ankle sprains. Eleven female college students with recurrent ankle sprains and seven students with no or a single prior sprain　participated. Ankle joint laxity was assessed using an ankle arthrometer with a 125-N load for anterior-posterior displacement and inversion-eversion rotation. Serum estradiol (E2) and relaxin-2 levels were measured. Ankle laxity assessments and blood sampling were performed in the follicular, ovulation, and luteal phases of the participant’s individual menstrual cycle. A significant group × phase interaction was found for inversion-eversion ankle joint laxity; however, post hoc analyses adjusted for Bonferroni multiple comparisons were not significant, implying a lack of clinical interest or potential sampling fluctuations. A positive correlation was found between serum relaxin-2 level and anterior–posterior ankle joint laxity during the luteal phase (r = 0.557, p = 0.048). This association should be interpreted as an observational finding that may help generate hypotheses regarding potential hormone-related factors in in ankle sprains in women.

Publication History

Received: 13 August 2025

Accepted after revision: 03 February 2026

Accepted Manuscript online:
04 February 2026