How common is concussion in rugby? It is hard to say how common concussion is as players often don’t admit to being concussed or there isn’t someone who can correctly diagnose concussion available at the time. How common concussion is also varies depending on the level of play; studies in professional rugby have shown that it occurs at a rate of about 3.9 per 1000 player hours (i.e. one concussion in every six games among all the players involved) whereas studies at amateur adult level suggest that concussion occurs at a rate of about 1.2 per 1000 player hours (i.e. one in every 21 games).