Madieu Williams suffered a concussion the first day he played organized tackle football. Twenty years later, he realized it.
At the first practice of his freshman year of high school, he absorbed a hit and began feeling a sharp headache. His coaches brought him off the field to let him recover.
The headache lasted into the night. It was with him when he woke up the next morning. But the cause was not officially diagnosed.
“Looking back on it and knowing what the science is saying now, that was a concussion,” Mr. Williams said.
Mr.