The purpose of this study was to clarify the characteristics of lower-extremity kinematics during the running of soccer players with chronic ankle instability (CAI) in comparison to those without CAI. Twenty-two male college soccer players participated in this study. Twelve players were assigned to the CAI group and ten players to the non-CAI group, and players were diagnosed according to the Cumberland Ankle Instability Tool. Kinematic data of the hip, knee, ankle, foot, and ground reaction force components during the stance phase of running were obtained using a three-dimensional motion analysis system. The results revealed that soccer players with CAI who landed with ankle inversion and other characteristic kinematics in their lower extremity during the stance phase of running were similar to those without CAI. These results show that running kinematics in soccer players are not affected by the presence or absence of CAI. Future studies based on the results of this study may contribute to the analysis of the risk of developing CAI during soccer and may also help prevent lateral ankle sprains.
