Concussion can be caused by body hits too

Because concussion is a type of mild traumatic brain injury (TBI), it’s often assumed there must be a blow to the head to cause its effects.

But that is not the case. In concussion, injury to the brain occurs when there is sudden acceleration or deceleration of the brain inside the skull, where it hits the side of the skull and/or twists on itself or deforms its shape, causing damage.

So anything that causes the brain to rapidly change direction with a big force of energy may cause concussion. That could be a sharp or dull blow to the head, a hit to the jaw, whiplash, or a tackle to the body.

While it's easier to generate a lot of acceleration if there’s a hit to the head, acceleration of the head is still generated when you tackle someone across the chest and the head accelerates or changes direction from body impact.

So, concussion should still be considered in sporting situations if a player has the symptoms but no obvious impact to the head.