Soccer’s Women’s World Cup is underway - moving the attention away from the recent FIFA bribery scandal and back on the field. But fans aren’t the only ones focused on what’s happening on the pitch. In the last couple of years, there’s also increased interest on safety in world’s most popular sport.
In this week’s Enlighten Me - Science Reporter Eli Chen takes us to the University of Delaware where researchers are tracking headers in women’s soccer to better understand the risk of concussions and other brain injuries that come with heading, with the help of wearable technology.
At 8 am, inside University of Delaware’s indoor turf field, the women’s soccer team is gearing up for practice. And they’re also participating in a scientific study.
Along with the coaches and trainers who are standing on the field, there are scientists -- two women just a few years older than the players themselves. They’re watching the players closely, jotting down notes every time a player heads the ball.
The data the scientists are gathering are part of an ongoing study at UD to track headers in soccer. Tom Kaminski, director of athletic training education at UD, has been tracking headers in the women’s and men’s teams at UD for 12 years.
“The interesting aspect of soccer is that heading is part of the game, so you can use your head to strategically move the ball, forward, pass to a teammate, score a goal. Because of that unique aspect, it provides us who look at concussions, brain injury... a unique opportunity to study what’s called a subconcussive impacts," said Kaminski. "The big unknown is what happens over time.”
There’s been a lot of attention on former football players, who later in life are diagnosed with neurodegenerative conditions, like chronic traumatic encephalopathy, as a result of brain injury over the years. But concern for soccer players is rising. Bellini, captain of Brazil’s 1958 World Cup champion team, was diagnosed with chronic traumatic encephalopathy after his death last year. Around the same time, Brandi Chastain, who scored the winning goal for the US in the 1999 World Cup final, voiced her support for ban heading in soccer for children under 14. She talked about implementing the recommendation from the Sports Legacy Institute, a sports safety advocacy group during an interview with the PBS Newshour.
“I want to eventually get to FIFA. That’s my goal, is to get to FIFA, our governing body of all international soccer and say, we recognize soccer has inherent risks. And heading is one of those risks,” said Chastain.
The adult brain has about a 100 billion cells, each of which are connected to thousands upon thousands of other brain cells. So one might say that the brain is wired, like a computer. Damage to a microscopic portion of the brain could affect our ability to do to simple, everyday things, like remember a phone number or decide what to eat for breakfast.
“The injury in concussions and subconcussive injury is when this very delicate network wiring is damaged," said Michael Lipton, a neuroscientist at the Albert Einstein College of Medicine in New York. "And what that means is that you can have a very small area of injury that has an effect on function and behavior, not because it’s knocking out a discrete part of the brain, but because it’s essentially it’s disconnecting the network cabling that’s allowing different areas of the brain to work together.”
Lipton published a study in 2013 in the journal Radiology, which demonstrated that players who frequently headed the ball performed worse on memory tests and had brain abnormalities similar to those with concussions.
But while a growing number of anecdotes and research point to a health risk that comes with heading over time-- at the moment, it’s not enough to tell players to stop heading the ball.
“By telling people not to head the ball, is there basis for telling people that? The truth is, the data doesn’t exist yet,” said Lipton.
So scientists are trying to define a safe threshold for heading. The answer won’t come easily because there are so many variables -- like a person’s age, the length of a playing career, men versus women, adult amateurs versus Division 1 college players or pros. And that’s just a few of them.
Nonetheless, Kaminski is up for the challenge, especially now that his research has gotten an upgrade.
“This was the first sensor of its type to be used in non-helmeted sports,” said Jaclyn Caccese, one of Kaminski’s graduate students. She’s holding a small, black band containing a sensor made by Triax Technologies, a Connecticut-based company.
“It’s a sensor that sits in a headband and the girls can put the headband around the head and it tracks the motion around the head in real-time,” said Caccese.
The sensor can track acceleration of the ball to the head in real time. It records impacts to the head in terms of G-force units. Above a hundred G-forces is considered to be a concussion. Below that is considered “subconcussive.” The sensor sends data back to Jaclyn’s computer and shows her instances of heading along a graph.
“When they head the soccer ball, you’ll see a double peak. You’ll see at least two peaks, that’s the head making contact with the ball, and the ball leaving, both which will produce a peak in acceleration,” said Caccese.
The Triax sensors can be pretty precise. The data can indicate whether the ball hit the player’s head directly, or if it hit them rotationally, or on the side. Rotational blows are more associated with concussions, as seen in other non-helmeted sports like boxing or martial arts.
Kaminski also has the players take physical exams, balance and neurological tests. He actually collaborates with Lipton, since Kaminski has all this long-term, biomechanical data and Lipton has the neuroscience expertise to bring a larger understanding to the effects of heading on the brain.
“One of the big questions I have is what happens to these girls over the course of their playing careers," said Kaminski. "Is there a cumulative effect between when they enter as a freshman and leave as a senior? We would hope that stays baseline, but the hope that is that it doesn’t drop off.”
Lipton emphasizes that there’s a lot of uncertainty in this area, especially since the effects might reveal themselves very far down the road. Bellini, for example, was initially thought to have died due to complications from Alzheimer’s disease.
“An important to keep in mind, is that they were seemingly okay for a very long time. And then they had a significant decline that led to their demise," said Lipton. "Now that’s not an indication that their brain was normal during all that time. The point is that if you have this repetitive injury, you are creating subtle types of pathology that can either lead to either a cumulative injury over time, or something that sets up your brain to be vulnerable to degenerative diseases in the future. People with histories of head trauma have a higher risk for things like Alzheimer’s and Parkinson’s.”
But Lipton notes there’s a caveat. You need a lot of data to prove a certain amount of heading from playing soccer could pave way to brain disease later in life. It’s possible scientists might eventually discover a threshold and define a limit for heading in soccer, the same way pitch counts in baseball are designed to minimize arm injuries. But right now - it’s still too early in the game for that.