A well-known phrase championed by Dr. Robert Cantu, and reaffirmed in this news article:
...high-schoolers are more vulnerable to concussion than younger athletes. "Their brains seem to be in a second window of development," Rieger explains. "Because of what's going on metabolically, the brain seems to be more vulnerable to injury and takes longer to recover." And, someone who has suffered one concussion is more at risk if they suffer another. The symptoms can last longer, and recovery can take longer.
If you are a parent or coach, and you're unsure how seriously a player was hurt, Rieger says pull them from the game. "When it doubt, sit them out."
