Football has come under fire as a potentially dangerous sport, as researchers have dug deeper into the serious, long-term impact of concussions.

And it's not just concussions that have raised red flags, but also  "sub-concussive" blows to the head -- which are strong, but don't cause a concussion.

New research from the Tulane Institute of Sports Medicine in New Orleans offers perhaps a bit of good news for the sport.

 

Scientists tracked more than 1,000 high school football players over the course of several years and checked their performance in basic cognitive tests. These players did not suffer concussions, and lead researcher Gregory Stewart says their cognitive skills remained intact.

"We know that if they don't actually sustain a concussion, the brain seems to take care and heal itself fairly well, such that there are no apparent long-term deficits and and no long-term problems that are coming from playing high school football," he said.

The findings might calm the nerves of worried parents who are reluctant to let their kids participate in the sport, he said.

"What we're finding is that just participating is not dangerous," he said.

Athletes still need to be aware of the dangers of concussions and receive appropriate rest and treatment if they sustain one, Stewart said.