You don't hit opponents head with your head at rugby, so concussion is not so common. The most frecuent problem is spinal cord injuries in scrum[1], which year

You don't hit opponents head with your head at rugby, so concussion is not so common. The most frecuent problem is spinal cord injuries in scrum[1], which year after year leaves some players paraplegic. [1] https://en.wikipedia.org/wiki/Scrum_(rugby_union)#Safety https://en.wikipedia.org/wiki/Scrum_(rugby_union)#Safety