(HealthDay News) -- Most concussions among high school and college football players occur during practice, a new study finds.
Data on more than 20,000 young football players across the United States revealed that more than 57 percent of concussed high school and college players were injured at practice, not games.
Among youth football players, almost half of concussions were sustained during practice, according to the study published online May 4 in the journal JAMA Pediatrics.
Evaluating and modifying techniques used during practice may offer opportunities for prevention, experts say.
"While it is harder to change concussion incidence during games without major rule changes, a substantial number of concussions occur during practice across all levels," said lead researcher Thomas Dompier, president of Datalys Center for Sports Injury Research and Prevention Inc., in Indianapolis.
Policy makers and coaches could reduce the odds of serious head injury by limiting player-to-player, or full body, contact during practices, Dompier said.
Dr. John Kuluz, concussion director at Nicklaus Children's Hospital in Miami, said he isn't surprised so many concussions occur during football practice.
"There are a lot of concussions occurring in practices, but of course there are a lot more practices than games," he said. Kuluz pointed out that, according to the study, younger players had about three practices for each game; high school players had about four practices for each game; and college players had nearly 10 practices for a game.
Despite the greater number of practices, games are still more dangerous in terms of head trauma, Kuluz said.
Kuluz agreed that modifying physical contact -- the main cause of concussions -- would help reduce the odds of injury.
"You can't eliminate all player-to-player contact in practice," he said. "But there are alternatives -- like hitting dummies or using sleds -- rather than hitting each other," he said.
As awareness of long-term brain trauma increases, sports-related concussions are a growing public health concern, the researchers pointed out.
Schools are more aware than ever of the risk of concussions, Kuluz said. "All the schools I talk to are aware that there is a big risk of concussion when you play football," he said.
The study results are based on an analysis of data from three sources: the Youth Football Surveillance System; the National Athletic Treatment, Injury and Outcomes Network; and the National Collegiate Athletic Association Injury Surveillance Program.
The researchers found that during the 2012 and 2013 seasons 1,198 concussions occurred -- almost 12 percent of them among youth athletes, 66 percent among high school players, and 22 percent on the college field.
In all, concussions accounted for 9.6 percent of reported youth injuries, 4 percent of high school injuries and 8 percent of college injuries, the researchers found.
During practice, concussion rates were lower among college players than among high school players, the study found.
In 2012 and 2013, youth football players had the lowest concussion risk -- less than 4 percent both seasons. The one-season concussion risk was highest in high school at nearly 10 percent, and college players at 5.5 percent, the researchers said.
Among kids ages 5 to 7 there were no football-related concussions during that study period, researchers say.
Each year, approximately 3 million youth athletes, 1.1 million high school athletes and 100,000 college athletes play football, the researchers noted.
"Across all levels of football, policy makers, coaches, researchers and sports medicine officials should continue to seek ways to reduce concussion incidence," Dompier said
For more about concussions, visit the U.S. National Library of Medicine.