Injury prevention

Document Type



The purpose of this study was to perform a kinematic analysis of a non-contact eversion ankle sprain case study that occurred in the National Football League (NFL). Model-based image-matching analysis was performed to quantify ankle joint kinematics for the eversion sprain. Foot orientations are reported relative to the shank segment. At foot-ground contact, the ankle joint was dorsiflexed, externally rotated but neutral in the frontal plane. Peak eversion (50°) occurred 0.2 seconds later, with a maximum velocity of 426°/s, while peak dorsiflexion (64°) occurred with a greater maximum velocity (573°/s). Rotation in the transverse plane remained constant through ground contact. For this case, the combination of dorsiflexion at foot-ground contact and rapid eversion is associated with a non-contact eversion sprain.