It happens in a heartbeat. One moment your teenager is going up for a mark at the local footy, or chasing a loose ball at netball, and the next they’ve come off second-best in a clash of heads. On weekend grounds right across Australia, head knocks are part of the game, but knowing how to respond to one is what keeps players safe. At community level, the person on the sideline is often a parent, a volunteer first-aider, a student trainer or a club runner rather than a doctor.

Concussion injuries are among the most common and often misunderstood types of traumatic brain injuries. Whether sustained during sports,...