Objective To investigate sex differences in lower limb biomechanics during single-leg drop landing in individuals with unilateral Functional Ankle Instability (FAI). Methods Twenty individuals with unilateral FAI (10 males/10 females) performed single-leg drop landings on unstable and stable limbs respectively. Kinematic data were captured using a Vicon motion capture system, and kinetic data were collected using force plates. Data were analyzed using a 2 × 2 (Sex × Side) mixed-design ANOVA. Results Significant main effects of Sex were observed for hip flexion and abduction angles at both IC and peak vGRF, with females showing greater hip flexion (p = 0. 005; p = 0. 023) and smaller hip abduction (p = 0. 026; p = 0. 003) than males. A significant main effect of Sex was also found for ankle inversion at IC, with females exhibiting greater inversion than males (p = 0. 005). For ankle plantarflexion at IC, a significant Sex × Side interaction was detected (p = 0. 020) ; simple effects analysis revealed that females had reduced plantarflexion on the unstable side compared to their stable side (p = 0. 010). For peak vGRF, a significant Sex × Side interaction was observed (p = 0. 013) ; post hoc tests indicated that females had higher peak vGRF on the unstable side than males (p = 0. 008) and their own stable side (p 0. 001). No significant differences were observed for knee joint angles, TᵥGRF, LR, ΔL, or K leg (p 0. 05). Conclusion Female individuals with FAI employ a hip-dominant compensatory strategy (increased flexion/reduced abduction) and exhibit greater ankle inversion than males. On the unstable side, they demonstrate reduced plantarflexion compared to their stable side. Males with FAI primarily adopt a joint stiffening strategy with restricted motion. Future research on FAI should incorporate sex differentiation in biomechanical assessments to develop targeted rehabilitation.
Cui et al. (Wed,) studied this question.