機能性足関節不安定症の若年女性における運動による身体機能の改善：バランス、足関節機能、および身体運動能力に対する8週間の構造化高強度サーキットトレーニングのランダム化比較試験

Prolonged sedentary behavior in women is associated with weakened lower-body musculature and increased risk of falls and injury. Although high-intensity circuit training (HICT) has been reported to effectively improve aerobic and anaerobic fitness in previously inactive individuals, few studies have evaluated its effectiveness in young women with functional ankle instability (FAI).

We aimed to evaluate the effect of an 8-week HICT program on balance, ankle stability, and physical fitness in sedentary young women with FAI.

This randomized controlled trial included 96 sedentary young women with FAI (aged 18-30 years, Cumberland Ankle Instability Tool (CAIT) < 25), who were randomly assigned to the HICT (n = 54) or control (n = 42) groups. The HICT group completed an 8-week program (3 sessions/week) with progressive intensity stages, whereas the control group maintained routine activity. A battery of outcomes was assessed before and after the intervention. The primary outcomes included objectively measured balance function and perceived ankle stability, whereas the secondary outcomes included body composition, body circumference, and physical fitness. Repeated-measures analysis of covariance was used to detect the time × group interaction effect, with adjustment for baseline values.

A significant time × group interaction effect (p < 0.05) was observed for balance function and ankle stability (F = 4.732-54.806, η ² = 0.048-0.496), body composition (i.e., reductions in hip and thigh circumference: F = 5.092-8.933, η ² = 0.061-0.213), and physical fitness (i.e., improvements in back and leg strength, flexibility, upper limb strength, and abdominal strength: F = 7.783-54.806, η ² = 0.082-0.386).

An 8-week HICT program appears to effectively improve balance and ankle stability in sedentary young women with FAI, providing preliminary evidence that HICT is a promising intervention for enhancing physical function and reducing the risk of falls and injuries in this population.