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This study examined an accidental ankle twist occurring during a single-participant study of the effects of traction on ankle biomechanics. One male participant performed a series of randomly distributed side-cuts and turns. In the 11th trial, the participant twisted his ankle during a side-cut. As no injury occurred, another 24 side-cut trials were recorded. Functional Data Analysis (FDA) demonstrated that the ankle twist trial was characterised by a sudden increase in inversion and internal rotation along with rapid transition from plantarflexion to dorsiflexion. Velocities showed a two-step increase in internal rotation and inversion, exceeding a 300 °/s safety threshold. The shift to dorsiflexion is indicative of an unloading mechanism that likely prevented the injury. FDA revealed variations between the ankle twist and the control that could inform stud design to prevent injuries.