Whatever the sport and level of play, impacts to the head from a ball, head, elbow, shoulder, knee and the ground all create rotational forces to the brain.

Rotational forces cause the brain to rotate inside the skull, brain cells to shear, fine blood vessels in the brain to be torn and the protective blood-brain barrier to be disrupted. This results in an abnormal and harmful uncontrolled inflammation which damages the brain. Repeated inflammations increase the risk of longer-term neurodegenerative consequences, including Chronic Traumatic Encephalopathy (CTE).

The brain is vulnerable to rotational forces from a single impact concussion and multiple sub-concussions received in sport. Sub-concussions are impacts that damage brain cell function, but do not produce evident signs or symptoms, so they go unnoticed by players and those around. The force to the brain to cause a concussion is 2-4 times greater than for a sub-concussion, but sub-concussions are over 500 times more frequent.

For children and youths experiencing head impacts, they have been found to have a higher risk of not achieving minimum standards for numeracy and reading in school, and demonstrated worse cognitive, planning, and new learning abilities as adults.