Major concerns lie with how frequent hits to the head can cause long-term brain damage.

Researchers are primarily interested in chronic traumatic encephalopathy (CTE), the brain degeneration caused by repeated head traumas. Microtubules, which transport materials in neurons, are supported by tau proteins; when microtubules are damaged, tau proteins can misfold and cause nearby molecules to do the same. The spread of these malfunctions results in CTE in some individuals. 

In a study examining the donated brains of 202 football players, CTE was found in 87% of brains examined. Just examine the 111 NFL players, and that number jumps to 99%—all but one had CTE. The study also shows a clear correlation between a longer football career and risk of CTE, with 91% of college players and 21% of high school players positive for the disease. For those with mild CTE, the most common cause of death was suicide, and for those with severe CTE, dementia- and parkinsonian-related causes of death were most prevalent.

But this fatal and incurable brain disease doesn’t just affect older players. A Boston University study found that participation in tackle football before age 12 “increased the risk of problems with behavioral regulation, apathy, and executive functioning by two-fold and increased the risk of clinically elevated depression scores by three-fold.” 12 is a key age when examining damage caused by youth football, as male children experience a critical period of brain development around this age. Previous research conducted by Boston University’s CTE Center found that NFL players who started playing football younger than 12 had worse memory and mental flexibility than their counterparts who began after that age. 

“It’s like smoking and cancer,” said Neurologist Bruce Miller about the link between head trauma and CTE. “It’s as clear as day.” An advertisement produced by the Concussion Legacy Foundation runs with this analogy—in the video “Tackle Can Wait,” young children are depicted lighting up cigarettes on the football field. As the camera pans over pre-teens in bright blue football uniforms exhaling smoke, the caption reads, “Kids who start tackle at age 5 vs. 14 are 10 times more likely to get the brain disease CTE.” “Tackle football is like smoking,” says the voiceover. “The younger I start, the longer I’m exposed to danger.”

Children are particularly susceptible to head injuries because they have larger heads relative to their body size, growing cartilage that can be damaged more easily, and less-developed motor skills that help older players avoid injury. Any injuries, not just those affecting the head, are likely to be more severe in a child than an adult. And concussions are a major concern when sustained by children with developing brains. 

It is important to state that football is not the only sport that poses a risk for young athletes. As many as 22% of injuries in soccer are concussions, and girls have higher rates of concussion than boys in the same sports. But of the almost 4 million recreation- and sports-related concussions that occur annually in the US, football has the highest risk, with an incidence rate of 10.4 concussions per 10,000 athletes.

Even just measuring concussions might not be enough to fully understand the issue. A growing body of research examines the effects of frequent subconcussive hits, or those that are less severe than concussions but still damaging. Football players are usually taken off the field and examined when showing signs of a concussion, but subconcussive impacts are commonplace during practices and games, resulting in long-term damage that goes undetected. 

One study estimates that college football players experience over 1,000 head impacts each season. Another study involving 38 college football players over three seasons reveals the danger of these hits: While only two players were diagnosed with concussions, “the comparison of the pre- and postseason MRIs showed more than two-thirds of the players experienced reduced the integrity of white matter—rigid brain tissue that serves as a connector to grey matter in the brain and damage to which causes disconnections among neurons, affecting perceptual speed and executive functioning—with more loss correlating with the number of head hits endured.” 

What does this mean for players? According to the Concussion Legacy Foundation, athletes who sustain more impacts suffer from decreased memory, as well as attention and behavioral problems; MRIs reveal decreased brain activity and structural damage to connections in the brain. 

“The risk of physical injuries, such as broken legs and torn ligaments, used to seem acceptable, given the merits of the game,” writes journalist Linda Flanagan. “But now players and their adult guardians must incorporate the uncertain prospect of irreparable brain damage, which reveals itself decades later, into their calculations. It’s one thing to be injured in the moment; it’s another to live for years with the spectre of possible harm still to come.”

Concern over this research has prompted many legislators to take action. Now, all 50 states have concussion laws that have greatly improved efforts to recognize and treat concussions, making it significantly unlikely that a young athlete will return to a game or practice while showing symptoms. Pop Warner, the largest youth football league in the country, limited full-contact practice time in 2013. This caution has reached other sports, with the US Soccer Federation banning headers for children under 10 and limiting them for children 11-13 in 2015. 

But parents focus most of their worry on football, with that concern increasing over the years. A 2018 poll taken just days before the 53rd Super Bowl found that almost half of all Americans would encourage a child interested in football to pursue a different sport because of concerns about concussions, an increase from 40% four years ago. This aligns with decreased participation in tackle football among children ages 6-12—half a million fewer children played in 2018 than 10 years prior.

However, there are plenty of benefits to youth sports, and few parents are willing to prohibit their children from participating just based on the injury risks. Playing sports at a young age can improve mental, social, and physical health. Kids who participate in sports have stronger muscles and bones and are at lower risk for diabetes, cardiovascular disease, and depression. Sports can teach kids the value of hard work and how to deal with failure, as well as set a routine of regular exercise that creates a foundation for lifelong health. 

Parents who want their children to reap these benefits but fear brain damage can consider different sports. Flag football actually has almost 100,000 more players ages 6-12 than tackle football, with 1.5 million players in 2020; girls and co-ed leagues are also more prevalent in flag than tackle football. With the American Flag Football League (AFFL) founded in 2017, this sport may provide a look into a safer future. According to the CDC, “[Y]outh tackle football athletes ages 6 to 14 sustained 15 times more head impacts than flag football athletes during a practice or game and sustained 23 times more high-magnitude head impact (hard head impact).” 

Former NFL Superstar Michael Vick says he was inspired by his daughter to get involved with the AFFL.

“My daughter, she’s a quarterback for her high school. I just thought that was so inspiring,” Vick told The Athletic. “I spent a lot of time around flag football, helping her coaches coach and putting plays together. It was an opportunity to get on the field and play. It was a small tribute to her and to show her the things I’ve been trying to teach her that really work.”

It’s important to note that research on concussions and CTE related to football is far from complete. The specific ways that head trauma results in the damage of tau proteins and CTE is unclear, and not everyone who incurs head impacts will develop neurological problems. Currently, a brain can only be examined for CTE in an autopsy, and years can pass between a traumatic head injury and the emergence of symptoms.

Studies conducted by the NFL or sports-injury researchers who work closely with professional or collegiate football teams raise eyebrows among some, and research more detached from corporate interests also has its faults. In the Boston University study referenced above, the 202 brains examined were all voluntarily donated by either the players or their families, possibly creating a bias towards players showing more severe symptoms of CTE. As Flanagan points out, “It’s not possible to conduct a randomized, controlled trial that measures the long-term effects of knocks on children’s heads; in the absence of such a trial, the existing evidence of long-term neurological harm in youth football is mixed.”

The risk posed by football should not be exaggerated. Very few people die from the sport at the youth level—in 2017, 13 of the over 4 million players—making reality a far cry from some early 20th century predictions. Changes in tackling techniques, improvements to helmet technology, and better protocols for recognizing and treating concussions have made football today safer than it has ever been.

It doesn’t seem like America is letting go of football anytime soon. And for good reason—countless athletes can attest to how the sport has enriched their lives, and the rich traditions many American high schools have surrounding the sport are irreplaceable.

But there are ways to make the sport safer, and there are legitimate concerns over how the sport is currently played—it doesn’t take an expert to see that. Ann McKee, Director of BU’s CTE Center, says it best: “It makes common sense that children, whose brains are rapidly developing, should not be hitting their heads hundreds of times per season.”