ObjectiveThe purpose of this pilot study was to document the nature and temporal profile of the clinical symptoms of acute sport-related concussion.DesignProspective cohort studyPatient PopulationA total of 303 elite Australian football players participating in a national competition during a single season.Outcome MeasuresNumber and duration of symptoms, digit symbol substitution test (DSST) scores, time of return to play post injury.ResultsA total of 23 concussions were recorded over the course of the 20-week football season. No catastrophic head injuries occurred. Headache was the most common symptom and the most persistent, with 40% of players reporting headache symptoms lasting more than 15 minutes. Ten of the players (43%) returned to sport on the day of the injury with the remainder resuming play within 2 weeks. A low likelihood of return to play on the day of injury was found where 3 or more symptoms were present or where the symptoms lasted more than 15 minutes. These findings were significantly correlated with poor DSST performance.ConclusionsThis pilot study suggests that both the number of postconcussive symptoms and their duration may be used as a measure of injury severity and a guide for return to play.