“As a society we need to question whether we should sanction and condone allowing our children at a young age to having their brains be jostled about inside their skulls hundreds of times per season,” says study author Robert A. Stern of Boston University.

The release of this study’s results comes just before the Super Bowl, the biggest football event in the world.

These results, plus others, are probably why there are fewer children playing tackle football every year. A recent Bloomberg poll shows that half of Americans now do not want their children playing the sport.

There is a growing concern in the U.S. that football is already a dangerous sport, with the rate of concussions sustained while playing football higher than any other sport. Just one concussion has lasting effects, including long-term brain damage.

In 2012, a study done by Virginia Tech used accelerometers in the helmets of young football players. That study’s results showed that the average number of impacts each player received was over 100 through the course of a single season. Some of those impacts were even as traumatic as those received during car accidents.

“While youth football players impact their heads less frequently than high school and college players, and have impact distributions more heavily weighted toward low magnitude impacts; high magnitude impacts still occur,” write the authors of that study. “Interestingly, the majority of these high magnitude impacts occur during practice.”

However now, this new study suggests that those who never suffer from a concussion still sustain some brain damage, which causes cognitive decline later in life. Of course, the study only focused on NFL players, who have spent most of their lives playing the sport, so we need more studies for those who aren’t professional players to verify these findings.