Doctors and public health experts are concerned about the effect of repeat concussions that occur before the brain has had a chance to heal from a prior impact.

More research on how they affect younger brains is urgently needed. In addition, coaches, parents and school officials need to pay closer attention to what is already known about the hazards of concussions and how best to prevent permanent damage.

via Concussion Is a Serious Problem for Child Athletes: Scientific American.