Trick question! You don’t actually have to hit your head to get a concussion.
Concussion is the result of acceleration and deceleration of the brain inside the skull. The easiest way for this acceleration or deceleration to occur is to receive a direct impact to the head, but even if there is no direct impact to your head, your brain can still experience some amount of acceleration or deceleration within the skull, which means a resulting concussion is still possible with a hard enough hit to the body.
Watch the video for a full explanation!