The United States Soccer Federation unveiled a series of safety initiatives Monday aimed at addressing head injuries in the sport, including a policy that sets strict limits on youth players heading the ball. The new guidelines, which resolve a proposed class-action lawsuit filed against U.S. Soccer and others last year, will prohibit players age 10 and younger from heading the ball and will reduce headers in practice for those from age 11 to 13.

The regulations will be mandatory for U.S. Soccer youth national teams and academies, including Major League Soccer youth club teams, but the rules will be only recommendations for other soccer associations and development programs that are not under U.S. Soccer control.

“What we’re establishing is creating parameters and guidelines with regards to the amount of exposure” to potential head injuries, George Chiampas, U.S. Soccer’s chief medical officer, said in a conference call with reporters. He added that the science on concussions and youth soccer was still evolving, and so would U.S. Soccer’s policies.

Among the other changes will be modifications to substitution rules that are meant to better serve players suspected of having sustained concussions. The specifics of the new policy proposals on substitutions will be announced in the next 30 days, according to U.S. Soccer.