With the start of a new school year comes another rite of fall, the return of high school sports.

Friday night lights. Homecoming. Gridiron glory. Concussions.

No one is eager to think about that last one. But it can't be ignored. And, from now on, it must be part of the playbook for high school coaches.

Under legislation signed last week by Gov. Jerry Brown, coaches are required to learn the symptoms of concussions and the appropriate medical response. The new rule, which takes effect Jan. 1, won't be limited to football coaches, and for good reason.

A study published in the Journal of Athletic Training found 36 concussions per 100,000 player games or practices in girls soccer. For boys soccer and girls basketball, the figures were 22 and 21, respectively.

As you might guess, the report said football has the highest rate — 47 per 100,000 player games or practices. Some other studies suggest head injuries may be more common, with as many as 20 percent of all high school football players suffering concussions annually.

The state's governing body for high school sports, the California Interscholastic Federation, already requires a signed medical release before an athlete who suffers a concussion or head injury is allowed to resume playing. By state law, parents must sign a head injury information sheet each year before their children are cleared to play school sports.

However, until now, there wasn't any requirement that coaches have formal training in recognizing and responding to concussions.

Responding to a combination of lawsuits and mounting scientific data, pro sports leagues are beginning to address the prevalence of head injuries with new safety equipment and by giving medical and training staffs greater authority to keep injured players off the field.

Some high schools are doing the same thing. One of them is Casa Grande High School in Petaluma, which has instituted an evaluation program to help identify and address head injuries.

Ensuring that coaches are equipped to recognize concussions will make high school sports, a staple in many communities, a safer experience for young athletes.

That should be a no-brainer.