When Jeffrey Vulk ran in high school in the 1990s and then played safety in college, he got tackled and rolled out countless times during full-contact football practice. He was a hitter and suffered many injuries, including concussions.
When he became a coach at Buffalo Grove High School outside Chicago in 2005, Vlk did what he was taught. He made his players hit and tackle in practice to “strengthen them”.
But by the time he took over as head coach in 2016, he had seen many players so badly battered after a week of practice that they missed games or were more susceptible to injury in games. bottom.
Therefore, starting in 2019, Vlk has abolished the practice of full contact. Once a week, players wore shoulder pads on Wednesday, which they called Contact Day. At that point, they hit tackle bags and crash pads, wrapped around their teammates, but didn’t throw them to the ground. Vlk said no starter has been injured during practice in the last four years.
“Those kinds of injuries can last for a long time, and just knowing that I am keeping my kids safe, both in the program and out of the program, is enough to get me down this road. It’s a reason,” he said.
Vlk’s approach of limiting a player’s hit count is slowly gaining ground in football, where much of the effort focuses on concussion avoidance and treatment, which often cause observable symptoms. shown and tracked by sports leagues.
However, researchers have long believed that the more an athlete receives a blow to the head (even a subconcussion that usually goes untracked), the more likely they are to develop cognitive and neurological problems later in life. have argued.
A new study published Tuesday in the scientific journal Nature Communications adds to the serious problem. A soccer player’s chance of developing chronic traumatic encephalopathy (CTE) is related not only to the number of head impacts absorbed, but also to the cumulative effects of all those impacts. .
The study, the largest ever to investigate the causes of CTE, used data published in 34 studies that tracked the number and magnitude of head blows measured by sensors in football helmets. bottom. Scientists used data going back 20 years to estimate the number and force of head blows absorbed by 631 former football players whose brains were donated to a study overseen by researchers at Boston University.
This paper sought to address one of the most enduring challenges for brain trauma researchers. It is to identify which aspects of a blow to the head contribute the most to her CTE. They looked at the number of blows to the head, years of playing football, the intensity of those blows, and the impact. other factors.
Studies have found that the best predictor of brain disease later in life is not the number of diagnosed concussions, but the cumulative force of head strikes an athlete absorbs over his or her career.
“We now have a better understanding of what causes CTE conditions, but we also know more about what doesn’t cause CTE conditions,” said Daniel Daneshvar, M.D., assistant professor of medicine at Harvard Medical School and lead author of CTE. I understand very well,” he said. the study. “And in this case, the largest study of CTE pathology to date, the concussion was basically the noise.”
Of the 631 brains examined, 451 players, or 71%, were found to have CTE, while 180 had no CTE. Athletes presumed to have absorbed the most cumulative force had the worst form of CTE, with symptoms such as memory loss, impulsive behavior, depression and suicidal ideation.
Erik Naumann, a professor of biomedical engineering at the University of Cincinnati who was not involved in the study, said the results support the idea that accumulation of subconcussions, rather than concussions, is the driving force behind long-term cognitive decline. Stated.
The latest data “certainly seems to support the idea that all these hits matter and that they all add up,” Dr. Naumann said. “When damage accumulates faster than the body can repair it, problems arise.”
He said the analysis points the way to tangible changes that could make football safer, such as the elimination of strikes in practice and the development of helmets that better absorb impacts, especially to the back of the head. Stated.
Naumann said the new study included brains from players with and without the disease, escaping the common concern that researchers are only looking at the most damaged brains.
It also found an association between the estimated number and types of blows players suffered during their careers and their health status years later, which led players to suffer unexplained injuries in the decades that followed. Dr. Naumann said this would make it difficult for detractors to claim that they may have suffered injuries. They quit soccer, which may have led to cognitive problems later on.
Dr. Naumann said the new research still has limitations. In this study, we counted all head impacts detected by helmet sensors, except those caused by collisions or accidental movements. However, previous studies have suggested that the most important hits appear to be those above a certain threshold, which we were unable to distinguish in this study.
The NFL doesn’t publish helmet sensor data, so the study used university sensor data as a proxy for professional players.
Helmets have improved in recent years, and players who had careers before the improvement may have absorbed more of the impact from a batted ball. But soccer players of decades ago were on average smaller and slower than those playing today, making any blow less powerful, Naumann said.
“It’s certainly a warning, but it doesn’t make you think the basic conclusion is wrong,” he said.
Professor Joseph J. Crisco of Brown University, who helped devised the sensors used in Liddell’s helmet, said the study had a fundamental problem: How many attacks did the brain donors accumulate over their career? He said he tried to overcome the challenge of not doing so.
Rather, this study used more recent player helmet sensor data to estimate the number and force of head impacts in older players based on what position, what level of sport, and how long they played. was estimated.
He said studies using real life head impacts in athletes are needed, but the results show that “the hardest, most frequently impacted athletes are more likely to develop CTE in the future.” said to suggest that
Steve Lawson, who studies helmet impacts and concussion risk at Virginia Tech, said the study’s focus on force and number of blows an athlete can withstand reflects how scientists understand brain injury. said to be consistent with
“Every time you hit your head, it puts a certain amount of stress on your brain, stretching the pressure response and the tension response, the brain tissue,” he says. “And above a certain threshold, some damage response is expected, and the severity of that damage response depends on the value of the acceleration.”
Researchers have successfully identified several factors that explain different players’ exposure to head impacts, he said. For example, linemen hit the front of their helmets most often, and quarterbacks are more likely to get severe rear impacts, he said.
But Dr. Lawson said people were wrong to think that the study could be used to predict someone’s likelihood of long-term cognitive impairment.
“I don’t think we can do anything at the moment is to look at individuals and figure out exactly if they’re exposed to head impacts compared to other people,” he said. I was. I have considered it enough. ”
The study notes that future studies should investigate different thresholds for counting hits, which is an important advance, Dr. Lawson said. Some blows to the head are so mild that the brain can probably withstand them, he said. But it’s not clear exactly when the effects will become damaging, he says.
“Not all influences are created equal,” he said. “I think trying to figure out which effects are most important can be very useful for this kind of analysis.”