INDIANAPOLIS (AP) — A study released Monday concludes that youth football coaches who are educated in the sport make the game safer for players.

The Indianapolis-based Datalys Center for Sports Injury Research and Prevention collected data from 2,108 football players ages 5 to 15 last fall. It found that players who competed for coaches who been trained in USA Football’s “Heads-Up Football” program were 34 percent less likely to get a concussion in practice and 29 percent less likely to get a concussion in a game.

The study was commissioned by USA Football, the sport’s national governing body.

Researchers also monitored blows to the head of 72 players ages 9 to 15. The organization monitored injuries of 100 teams in 10 youth leagues and four states.

INDIANAPOLIS (AP) — The National Federation of State High School Associations has changed a football rule involving unnecessary roughness to minimize the risk to players.

The association said Friday that its board of directors has approved revising the rule to ban unnecessary roughness against defenseless players. The group also has revised its spearing rule. That rule now bans players contacting an opponent at or below the shoulders with the crown of their helmets.

Brad Garrett is chair of the NFHS’s football rules committee. He says minimizing risk to players must be “at the forefront of the game.”

The association says its 2013-2014 survey shows football is the most popular high school sport for boys with more than 1.09 million players. About 1,800 girls played football during the 2013-2014 season.