Groups in four states are pushing to raise the age for tackle football and do more to protect young athletes from traumatic brain injuries.

Former high school linebacker Brody Kieft, now 21, played football with the energy and aggression of a heat-seeking missile, which earned him cheers from the fans, interest from the college scouts, and a worrisome list of head concussions.

Kieft is from Muskegon, Michigan, a city with a proud football heritage. He started in a youth football league at the tender age of 6. His early years were unremarkable in terms of documented injuries, but things changed his first year at Muskegon Catholic Central High School when he fielded a punt without first waving for a fair catch. “I got straight clobbered; I got murdered,” he recalled.

The promising Crusaders freshman said he had been keeping his eye on the ball when he was hit under the chin by “the baddest dude on their team.”

The game — and the season — ended for Kieft with his two younger sisters badly shaken and in tears while he was placed in a neck brace and loaded into an ambulance. This was followed by a 50-mile drive to Helen DeVos Children’s Hospital in Grand Rapids, his anxious father at his side.

“In the ambulance, I was scared,” Barry Kieft said. “I was really scared. I could see it in his eyes that he was really sick.”

Number 6 did not play another down the rest of the season, and the team trainer even refused to show Kieft video of the play that had knocked him out of the game.

Before his 2013 freshman school year started, Kieft had taken a baseline test called ImPACT, which stands for Immediate Post-Concussion Assessment and Cognitive Test.

It assists in the screening, assessment, and management of concussions for various groups at risk, such as high school or college athletes and those who participate in sports leagues. Kieft’s results were stored in the program to serve as a baseline. Any injury he sustained later could be evaluated by taking a subsequent test, with results compared to that baseline.

This helps an organization manage a student’s recovery and determine when they may return to play following a head injury.

Kieft remembered: “The test was based on words, memory, line patterns, colors in boxes — nothing hard, but you have to go back and take the test again, and the team doctor compares it to your baseline test. I took it every week after that freshman concussion and didn’t get a certain number correct, so that was considered a ‘fail’ and the reason I didn’t play again that season.”

Kieft’s sophomore year was officially uneventful. However, he remembers that he had several head injuries.

“I didn’t bring it up or say anything,” Kieft said. “You just want to keep playing. Unless you say something is wrong, the coaches are focused on the plays and winning and whoever the next opponent is. They’re not looking for those kinds of things, especially not at practice.”

Two California State Assembly members, Kevin McCarty (D-Sacramento) and Lorena Gonzalez Fletcher (D-San Diego), announced in February the Safe Youth Football Act, a bill that would allow contact football programs only at the high school level, banning youth tackle football.

According to the press release, the bill “will prevent young athletes from sustaining long-term brain damage caused by repetitive tackling, hitting and blocking.”

They were, of course, referring to their aim of preventing future chronic traumatic encephalopathy (CTE), a progressive degenerative disease of the brain found in individuals who played contact sports with histories of blows to the head. The condition right now can only be diagnosed at autopsy.

“Children who play contact sports during their most critical years of brain development are at a significantly greater risk for neurological impairments and CTE later in life,” the press release said. It goes on to quote Bennet Omalu, MD, author of “Concussion,” a book on CTE:

“The research is clear — when children participate in high-impact, high-contact sports, there is a 100 percent risk of exposure to brain damage and once you know the risk involved in something, what’s the first thing you do? You protect children from it.”

Legislation has also been introduced in Illinois, New York, and Maryland to prohibit children under high school age from playing tackle football.

A new study in the medical journal Brain found that repeated hits to the head can also lead to CTE, not just the blows that produce an actual significant injury or concussion.

Researchers examined brains from four deceased teenage athletes. They found that closed-head impact injuries, independent of concussion status, can induce sports-related traumatic brain injuries, as well as early indications of CTE.

This study shines a light on the risks for younger athletes of long-term neurological conditions from having played contact sports in their youth. It suggests that impacts involving the head can damage the brain’s blood vessels and cause a cascade of inflammatory cells.

This may make the brain more vulnerable to CTE, which causes the protein tau to form sticky clumps that spread throughout the brain while killing brain cells in a scorched-earth fashion.

And now two California mothers of athletes found to have early signs of CTE at autopsy are suing Pop Warner Little Scholars (PWLS), the largest youth football, cheer, and dance program in the world. Jo Cornell of Rancho Bernardo, an affluent San Diego suburb, and Kimberly Archie of North Hollywood claim they lost their sons as a result of head injuries they sustained playing football beginning at a young age.

The lawsuit was filed in federal court in Los Angeles on Sept. 1, 2016. It accuses Pop Warner, a nonprofit tackle football organization, of failing to set the safety bar high enough to keep the 325,000 youngsters who participate each year from suffering head injuries and concussions.

The lawsuit was filed in the U.S. District Court for the Central District of California by Tom Girardi, the Los Angeles attorney who obtained fame by winning what is known as the Erin Brockovich case.

U.S. District Judge Philip Gutierrez recently ruled that most of the claims in the case against Pennsylvania-based Pop Warner, including allegations of negligence and fraud claims on the grounds they misrepresented the level of safety procedures and protocols, could move forward.

Cornell’s son, Tyler, ended his life in 2014 at the age of 25 after years of mental illness. He had played football starting at the age of 8 up until he was 17, and he didn’t have any documented concussions according to the suit. His brain was given to Boston University researchers, who found the markers of CTE in the young man’s brain.

Archie’s son, Paul Bright, played football for eight years starting from when he was 7 years old. He too ended his life unceremoniously on a motorcycle at the age of 24; his brain was also diagnosed with signs of early CTE.

The mothers are on a mission that advocates for changes in the way football is played with limits on the amount of contact the younger players can have. They want safer helmets too.

Kieft had worked hard the summer before his junior year and, bulked up to 170 pounds, was ready to play.

During one particularly hard-hitting game, a wobbly Kieft came off the field after being kicked and punched in a pileup. It was a concerned teammate who tipped off the trainer that Kieft didn’t look right.

“We went in for halftime, and she didn’t let me play after that,” Kieft said. “I was vomiting and nauseated and later, I couldn’t pass the ImPACT concussion test, and I didn’t play another down that year, either.”

Kieft’s concerned father followed up with an appointment with a neurologist who sent him for neuropsychological testing. According to the report: “Most test performances were within expectation, although some weaknesses were noted in certain complex cognitive — mostly executive — functions,” said the report. It went on to state that while Kieft’s performance was below average in some areas, it was not “necessarily impaired.” In fact, he scored above average in many of the tests, and most of the scores by this time had improved from the ImPACT scores of post-injury testing.

Kieft was allowed to suit up in his senior year on the condition he would play a position that minimized his injury risk. Even then, he believes he may have suffered “one or two concussions.”

“If I had to guess, sure I had one or two concussions, but I pushed them off as headaches,” said Kieft.

“The rewards are worth the risk; I would not have ended my football career because I was worried about head injuries, although I know other people who have. All you want to do is play and to win.”

In Kieft’s senior year, he was recruited by numerous small colleges but changed his mind about attending the one he chose just a few weeks into early season football practice. “When I was a kid, I thought I was invincible, but I’m older now, and I’m not so sure of that.”

That ever-present tipping point between invincibility and vulnerability was on Kieft’s father’s mind as well.

“Are some brains more fragile than others? How is it that so any people have played football over the years, and they are fine for the rest of their lives?” Barry Kieft said.

He added: “The most amazing years of my life were spent watching my son play football. The championship games he played in at Ford Field in Detroit, I wouldn’t want him to have missed those experiences. There were tears of sadness in his eyes when he couldn’t play and tears of joy in his eyes when he could play. It’s bittersweet that it’s over, but I don’t have to worry anymore; I was always a nervous wreck sitting on the edge of my seat worrying about him. Brody is happier now than I have ever seen him.”