['To identify factors that predict running ability following traumatic brain injury (TBI), and to quantify performance thresholds for these predictors.', 'Cross-sectional cohort study.', 'One hundred fourteen people with TBI.', 'Self-selected walking speed, the high-level mobility assessment tool, postural stability (lateral center of mass displacement), ankle power generation at push-off and quality of gait performance (Gait Profile Score).', 'All predictor variables were all strongly associated with the ability to run. However, only self-selected walking speed contributed significantly to the final result. Investigation of performance thresholds for self-selected walking speed indicated that following TBI, people who walk at speeds of 1.0 m/s or higher are 16.9 times more likely of being able to run than for those who walk at speeds of less than 1.0 m/s.'] Does self-selected walking speed predict ability to run following traumatic brain injury?