2021-05-08: Teenage girls face almost double the risk of concussion playing soccer, compared with teenage boys (risk ratio 1.88, 95% confidence interval 1.69 to 2.09, P<0.001)…. Reported by Gareth Iacobucci.
COMMENT: This report is based on a good study and is to be believed, but it raises a question: what’s the difference between boys and girls?
The two explanations I can think of are: (1) Concussion in soccer is due mostly to blows to the head sustained in “heading” the ball …. when something hits the head, the blow is transmitted to the brain under the point of impact, causing the brain to move. The moving brain then hits the opposite side of the skull with equal force (“contrecoup”) and each time the ball is “headed” the brain gets two “hits”. So, since males have stronger neck muscles, the sudden movement of the head in heading, and the “front and back” impacts sustained by the brain, are less. (2) If the player moves the head to strike the ball actively, the force of the “hit” is greater, but the brain-jiggling jerk of the skull is less. Maybe girls head passively, allowing the ball to hit the head without tensing the neck muscles. If so, the jerking of the skull must be greater and the back-and-forth “jiggling” of the brain much more pronounced.
NOTE: The brain is a jelly, with connecting nerves running through it which are made of slightly stronger, but really fragile, jelly. Rapid jiggling causes stretching and tearing of the nerves every time the skull receives a shock. Therefore concussions are cumulative: repeated small injuries add up to real problems.
POSSIBLE SOLUTIONS: (1) Change the rules, to outlaw heading, or (2) Teach girls active heading and (3) Include neck-strengthening exercises in training programs.