The Research

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.”