Relationship Between Ankle-Joint Angle During Dynamic Balance Task and Ankle-Joint Proprioception in Chronic Ankle-Instability Individuals

BACKGROUND: Chronic ankle instability (CAI) is a major condition in athletes. It is known that both ankle joint proprioception and joint mo-tion control are important for the improvement of CAI, but the relationship between the two has not been clarified. The purpose of this study was to compare ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in healthy and CAI individuals and to verify the relation-ship between ankle-joint angle in dynamic balance tasks and ankle-joint proprioception in individuals with CAI. METHODS: The participants were 27 females (age 20.3 +/- 0.9 years, healthy group: 15, CAI group: 12). The star excursion balance test (SEBT) was used for the dynamic balance task, and the ankle joint angles were measured with a small accelerometer during the movement. The error of the active joint repositioning test (AJRT) was measured to test the proprioception.RESULTS: There was no significant difference in the error in AJRT between the groups, but the joint angle in SEBT was significantly lower in the CAI group than in the healthy group for ankle dorsiflexion only. The error in AJRT of ankle inversion was correlated with the ankle inver-sion/eversion angle of the SEBT, and the error in AJRT of ankle plantar flexion was correlated with the ankle-dorsiflexion angle of the SEBT.CONCLUSIONS: CAI individuals showed no difference in ankle-joint proprioception compared to healthy individuals, but their ankle-joint-dorsiflexion angle in the dynamic balance task was smaller. Ankle-joint proprioception in CAI individuals was related to the ankle-joint angle in the dynamic balance task.