(FILES) Seattle Seahawks' running back #09 Kenneth Walker III holds on to the ball as he collides with New England Patriots' cornerback #07 Carlton Davis III during Super Bowl LX between the New England Patriots and the Seattle Seahawks at Levi's Stadium in Santa Clara, California on February 8, 2026. At least a quarter of National Football League players may end up with a degenerative brain disease, according to a new study published on August 25, 2026, that lays bare the extreme toll of America's favorite sport. Chronic traumatic encephalopathy (CTE) is caused by repeated head impacts and its symptoms include trouble with thinking and memory loss, difficulty walking, emotional instability and suicidal thoughts. (Photo by Patrick T. Fallon / AFP via Getty Images)