Responding to concerns over brain injuries, California implemented a new law that limits the amount of full-contact football practices at schools. The law took effect Jan. 1 and applies to all middle and high schools, including private schools.

The law limits full-contact practices to two 90-minute sessions per week during the season and preseason, and prohibits full-contact practices during the off-season. Before the new law, coaches could hold full-contact practices daily. The law also forces schools to bench players for at least a week if they suffer a concussion. Former rules allowed players to return within a day.

Nearly 4 million high school students nationwide suffer head injuries every year, according to the U.S. Centers for Disease Control and Prevention.