Background: Chronic ankle instability (CAI) is a prevalent condition among Taekwondo athletes, often associated with pain, psychological factors, and impaired physical performance. However, few studies have investigated the relationship among ankle muscle strength, pain, kinesiophobia, and physical performance in Taekwondo athletes with CAI. Objects: This study aimed to examine the relationship between ankle muscle strength, pain, kinesiophobia, and physical performance in Taekwondo athletes with CAI. Methods: Forty Taekwondo athletes with CAI participated in the study. Pain was assessed using the Visual Analogue Scale (VAS), and kinesiophobia was measured with the Tampa Scale for Kinesiophobia-11 (TSK-11). Physical performance was evaluated using the single-leg vertical jump (SLVJ) and single-leg hop for distance. The strength of the ankle muscles is measured using a Smart KEMA strength sensor. Pearson’s correlation coefficients were calculated to determine relationships among variables. Results: SLVJ showed a significant negative correlation with VAS (r = –0.506, p < 0.01) and a positive correlation with strength of the ankle inversion with dorsiflexion (IDF) (r = 0.356, p < 0.05). VAS was negatively correlated with strength of the ankle eversion with plantarflexion (r = –0.365, p < 0.05), IDF (r = –0.371, p < 0.05) and inversion with plantarflexion (r = –0.370, p < 0.05). No significant correlations were found between TSK-11 and physical performance, pain, or ankle muscle strength outcomes. Conclusion: Pain intensity and ankle muscle strength in specific ankle positions are associated with SLVJ in Taekwondo athletes with CAI. These findings suggest that the intensity of pain and the strength of the ankle evertor and invertor at specific ankle joint positions should be considered when evaluating Taekwondo athletes with CAI. Furthermore, managing pain and implementing strengthening exercises for the ankle evertor and invertor can be recommended to improve SLVJ.

Background: In Taekwondo athletes, ankle sprain is the most common risk factor for injury. Repeated ankle injuries lead to weakness and imbalance of the ankle muscles, resulting in chronic ankle instability (CAI). Both the ankle and toe muscles contribute to the inversion and eversion of the foot at the subtalar joint. Therefore, it is necessary to consider the ankle and toe joint positions when measuring ankle invertor and evertor strength. Objects: This study aimed to compare the muscle strength and ratio differences of the ankle invertor and evertor muscles in both the toe and ankle positions between the CAI and uninjured sides in Taekwondo athletes. Methods: Fifteen Taekwondo athletes participated in this study. The isometric strengths of both the ankle invertor and evertor were determined in different ankle and toe positions (dorsiflexion with toe extension, dorsiflexion with toe flexion, plantarflexion with toe extension, and plantarflexion with toe flexion). Paired t-tests were used to determine the differences between the ankle invertor and evertor in strength and ratio according to toe and ankle positions between the ankle CAI side and the uninjured side. Results: The results demonstrated that ankle evertor strength significantly decreased in all ankle and toe positions on the CAI side (p < 0.05). In addition, significant differences were observed in the ratios of the ankle invertor and evertor strengths in the dorsiflexion with toe flexion, plantarflexion with toe extension, and plantarflexion with toe flexion positions (p < 0.05). Conclusion: The findings of this study suggest that athletes, trainers, and clinicians should consider ankle and toe positions when measuring invertor and evertor strength and develop ankle rehabilitation protocols for Taekwondo athletes with CAI.

Background: Landing from a step or stairs is a basic motor skill but high incidence of lateral ankle sprain has been reported during landing with inverted foot. Objects: This study aimed to investigate the effect of landing height and visual feedback on the kinematics of landing and supporting lower limbs before and after the touch down and the ground reaction force(GRF)s. Methods: Eighteen healthy females were voluntarily participated in landing from the lower (20 cm) and the higher (40 cm) steps with and without visual feedback. To minimize the time to plan the movement, the landing side was randomly announced as a starting signal. Effects of the step height, the visual feedback, or the interaction on the landing duration, the kinematic variables and the GRFs at each landing event point were analyzed. Results: With eyes blindfolded, the knee flexion and ankle dorsiflexion on landing side significantly decreased before and after the touch down. However, there was no significant effect of landing height on the anticipatory kinematics on the landing side. After the touch down, the landings from the higher step increased the knee flexion and ankle dorsiflexion on both landing and supporting sides. From the higher steps, the vertical GRF, anterior GRF, and lateral GRF increased. No interaction between step height and visual feedback was significant. Conclusion: Step height and visual feedback affected the landing limb kinematics independently. Visual feedback affected on the landing side while step height altered the supporting side prior to the touch down. After the touch down, the step height had greater influence on the lower limb kinematics and the GRFs than the visual feedback. Findings of this study can contribute to understanding of the injury mechanisms and preventing the lateral ankle sprain.