Women soccer players face a greater risk of serious injury when heading the ball than men, according to researchers. 

The risk for concussion can be so great, it was the focus of a discussion at Manchester United’s annual sports medicine conference that should have taken Thomas Kaminski across the pond. Instead, because of coronavirus pandemic travel issues, the University of Delaware professor in the Department of Kinesiology and Applied Physiology in the College of Health Sciences joined the conference virtually.

Kaminski, a leading expert with decades of experience in research in this specialized area, was invited to speak at the conference in a discussion entitled, "Medical and Scientific Challenges in Women's Football."

“I’m humbled by the opportunity,” said Kaminski. “Because Manchester United, arguably, is the most popular brand of soccer in the world in terms of professional league...it’s top shelf stuff.” 

Kaminski told an audience of more than 850 people from around the world that the risk of heading in soccer, or football as they call it in England and much of the world, may be linked to neck strength.

“Females, traditionally, have a little lower neck strength than males do,” Kaminski said. “So, when they go up for these — they're called aerial challenges — when two people go up in the air for the ball, protecting your space...that is a very vulnerable time for injury and concussion.”

Women, he said, also tend to report concussions more than men, which could be a factor in higher documented rates.

In the United States, heading is banned during play among children ages 10 and under. Between the ages of 11 to 14, Kaminski said, it’s critical that youth learn the proper technique. Many coaches, though, remain reluctant and underprepared to teach the integral skill. 

The possibility of concussion comes not from one hitting their head against the ball, but rather from two heads colliding or a person taking an elbow or shoulder to the head, Kaminski said. It’s these types of collisions or unintentional contacts that can lead to dangerous injuries. 

“So, it’s really about protecting that space,” Kaminski said. “Teaching them that skill [when they are] young to be able to do that is really important. And part of that is neck strength, so part of the Get aHEAD Safely in Soccer [program] is about teaching kids how to strengthen their necks.” 

Kaminski is UD’s director of athletic training education, so he played a pivotal role in developing Get aHEAD Safely in Soccer in conjunction with United Soccer Coaches. The first-of-its-kind interactive online course can certify coaches in safe, purposeful, and effective heading techniques. For pre-teen and teen soccer players, who go on to play at the collegiate or professional level, these skills can mean the difference between a safe header and a traumatic brain injury.

“Using lightweight soccer balls — they look and feel like a soccer ball — but they weigh like a beach ball,” he said of one training tool. “Kids are much more likely to head balls when it doesn’t hurt, and so we teach them while young, the technique...and hopefully that spills over, and they’re going to protect themselves.” 

Kids may not get an opportunity to head the ball much on the field, but female professional players can do so as much as 10 times in a single game. Former professional American soccer player Abby Wambach has likely headed the ball more than 10,000 times in her 30-plus-year career and has had just one documented concussion, according to Kaminski.

He painted a clear picture for his virtual audience.

“The analogy I like to use with my students is — it’s analogous to ice cubes in a glass of ice water,” Kaminski said. “The glass being the skull, and the ice cubes being the brain, and the water being the cerebral spinal fluid.”

The risk of subsequent concussion rises with every concussive episode, making heading the ball a risky play for some.

“That’s why we shudder in sports when a kid gets a concussion, it puts them at a much greater risk,” he said. “We’ve got girls on our women’s soccer team [at UD] with four or five concussions. By that time, I’m saying to myself, ‘it’s time for me to retire,’” said Kaminski. “There’s a cumulative effect, having one makes you more prone to having three.”

The recovery stretch is also longer, and at times, more difficult, following each concussion.

“Especially, in our collegiate population, those who’ve had previous concussions, typically, it doesn’t take too many headers for them to start to feel the ill effects — headache, dizziness,” Kaminski said. “So, what we’re seeing is that those individuals who’ve had multiple concussions don’t head the ball, because they’ve wised up. They say, ‘you know, it’s not worth it. I’ll play it to my chest or a play to my legs.’”

Kaminski said recovery time after concussion is also key.

“We need to treat them seriously, so what’s the hurry?” Kaminski told the virtual audience. “I consistently tell my colleagues here in the United States, what is the hurry with concussion and concussion management? If we hold an athlete back just for a few more days, I think it’s going to be more beneficial.”

But the “big elephant in the room,” as Kaminski described it, is what happens every time a player heads the ball. These subconcussive or repetitive head impacts are blows to the heads that don’t cause concussion.

“That’s an impact to the brain,” Kaminski said. “The brain moves ever so slightly, and what happens over time, we just don’t know. We think there’s probably some threshold that you have so many headers up to a certain point, and then you get past that threshold, and you’re much more vulnerable to problems in the future.”

What happens long-term, after one suffers from repetitive head impacts or concussions, is part of a longitudinal study that’s underway.  

UD was one of 30 institutions to participate in the NCAA-U.S. Department of Defense Concussion Assessment, Research, and Education Consortium Project, the largest concussion and repetitive head impact study in history. The project, launched in 2014, sought to examine the natural progression of concussions in collegiate athletes in the U.S. With more than 52,000 enrollments and 5,000 concussions, the study has concluded and entered the longitudinal phase, where some players will be monitored for the next two to three decades.

“They’ve been very willing participants to allow us to look at the outcomes of head impacts to their head from primarily purposeful heading,” Kaminski said. “We have a lot of data on our UD athletes, both men and women, and to be able to follow them into the future to see potential changes. Many of them have graduated and gone on to have kids, and families, and jobs, and live their lives. The question that remains and the big unknown is whether or not their brains have experienced any detrimental changes as they grow older and move into the future?”