Keishaud White, No. 5 on the Desert Vista High School Thunder football team, kneels at the southeast corner of the field before the first game of his senior year.

He’s praying — and in the audience, so is his mom, Keisha Culver.

“I just keep it in my prayer that he comes off the field the same way he went on and that’s unscathed, unharmed,” she said.

This is also Keishaud’s first game back after tearing his meniscus last season.

Minutes later, she lets out a cheer.

“Go Thunder! Go Keishaud White! It’s his senior year so hopefully he gets out there, he grinds, he makes his mama proud,” said Culver.

Around the country and the Valley, fall Friday nights will smell like kettle corn and sound like marching band renditions of fight songs and cheers from the crowd.

The number of boys playing high school football in Arizona dropped 15 percent in the past year, in line with a national decrease. In the 2016-17 school year, 17,761 Arizona boys played high school football.

Participation numbers have fluctuated from year to year.

An increased awareness of the lasting effects of brain injuries has changed the way Arizona teens play the game.

For example, a study published last month in the Journal of the American Medical Association found a degenerative brain disease in 110 of 111 donated brains from deceased former NFL football players.

Culver said her son has had a few close calls with head injuries, but has never been diagnosed with a concussion, a type of traumatic brain injury that usually has temporary effects.

Part of the reason she said she’s not worried is the staff of athletic trainers on the sidelines at this game and at every varsity football practice at Desert Vista.

Steve Baca is the head athletic trainer and he says as awareness of head injuries increases, the more student athletes report them. He estimated he might do 30 concussion evaluations in a football season.

Here’s what he looks for:

“The big one is a headache, that’s usually the first one that we see and the last one that we see to leave after someone suffers a concussion,” Baca said. “There’s a whole range of symptoms we can have from vomiting to balance problems to feeling foggy, to having trouble in school.”

Sports medicine physician Dr. Amy Overlin oversees the trainers in the Tempe Union High School District. She said says medical professionals need the cooperation of kids and parents to do their job.

“Concussion is difficult to diagnose because it is a constellation of signs and symptoms plus physical exam findings,” Overlin said.  “If people aren’t telling us what’s going on, it’s very hard to evaluate.”

Longtime coaches say these types of discussions are a huge departure from decades past.

“In high school, as kids made big hits, what we called ‘de-cleaters’ where the kids kinda got their bell rung, they would show that over and over,” said David Hinds, who coached in the ’70s and ’80s.

Hinds is now the executive director of the Arizona Interscholastic Association (AIA).

The group began mandating a concussion education program for student athletes in 2011.

“Part of education is making sure you’re doing things to prevent an injury to begin with,” said Dr. Javier Cárdenas, a member of the AIA’s sports medicine advisory and director of the Barrow Concussion and Brain Injury Center at Barrow Neurological Institute.

The AIA is also changing the way football is played, limiting the number of contact practices and banning blindside blocking. These rules have since been adopted nationally.

“At the end of the day we’re not going to talk parents into playing a certain sport of out of playing a certain sport,” Cárdenas said.

The Barrow Neurological Institute also conducts online surveys of Valley parents. The most recent found one-third of parents wouldn’t allow their kids to play football, a consistent finding since 2014. The percentage of adults that considered a concussion a “serious medical condition” has increased over the years to 90 percent.

One Valley parent with her eyes on the latest research is Laura Rodriguez, an Ahwatukee mom of two boys, almost 12 and 13 years old.

She’s from Texas where “football is life.”

Her son’s played flag football last year and she was surprised by how rough the sport could be. One son had a tooth knocked loose after a hard hit.

“You don’t want to set your kids up for injuries that will affect them for a lifetime,” Rodriguez said.

Club sports and leagues like the ones her sons played in aren’t regulated by an agency such as the AIA and can have less comprehensive education requirements.

“I don’t think sports are bad, I think it’s great that kids are active,” Rodriguez said.

Rodriguez has seen the consequences of serious brain injury firsthand. Her boyfriend deals with emotional and physical difficulties from a brain injury he got while in the military.

“If we’re not aware of what can happen or we don’t know how to react to what’s happening or how to help a child that may be hurt then we’ve failed our children,” she said.

For this year, Rodriguez is grateful her sons have chosen different extracurricular activities, band and cross country. She’s not sure what she’d do if they wanted to play tackle football in the future.