Lower limb kinematics during single leg landing in three directions in individuals with chronic ankle instability.

Objectives: To compare the lower limb kinematics of participants with chronic ankle instability (CAI) and healthy participants during forward, lateral, and medial landings.

Design: Cross-sectional study.

Setting: Laboratory.

Participants: Eighteen athletes with CAI and 18 control athletes.

Main Outcome Measures: Hip, knee, and ankle joint kinematics during forward, lateral, and medial single-leg landings were compared between the groups using two-way ANOVA for discrete values and statistical parametric mapping two-sample t-tests for time-series data.

Results: The CAI group had significantly greater ankle dorsiflexion than the control group (P ≤ 0.013), which was observed from the pre-initial contact (IC) for lateral and medial landings and post-IC for forward landing. The CAI group showed greater knee flexion than the control group from the IC for lateral landing and post-IC for forward landing (P ≤ 0.014). No significant differences in ankle inversion kinematics were found between the CAI and control groups. Lateral landing had a greater peak inversion angle and velocity than forward and medial landings (P < 0.001). Medial landing had a greater inversion velocity than forward landing (P < 0.001).

Conclusions: This study suggests that individuals with CAI show feedforward protective adaptations in the pre-landing phase for lateral and medial landings.