Studying ‘subconcussions’ to preserve safety, fun in youth sports

Indiana University is at the forefront of neuroscience research that could identify new ways to protect young athletes from risks associated with repeated, small blows to the head.

Kei Kawata, a research scientist at IU and former athletic trainer for professional sports, is leading the country’s largest study of subconcussive impacts in high school football players.

“It used to be we didn’t know anything about blows to the head in American football because the research wasn’t there,” said Kawata, a clinical neuroscientist and an associate professor in the IU School of Public Health-Bloomington. “Now we know a lot — there are accepted protocols for assessment and recovery — but we still don’t know much about smaller, repeated impacts in younger players.”

As a former athletic trainer for the Detroit Lions and Sporting Kansas City, Kawata is an expert on sports performance and safety. As a former high school soccer player whose son now plays, he also knows the passion and skills that team sports inspire in young people.

“If you go into a high school as a hardcore neuroscientist and ask coaches to enroll their students in a research study, they will say no,” Kawata said. “But my experience as a sports medicine trainer gives me ‘street cred.’

“I’m not here to demonize football.”

Since 2019, Kawata has studied high school football players across Indiana under a $3 million grant from the National Institutes of Health. Indiana schools participating in the study have included Bloomington North and Bloomington South High Schools, Edgewood High School, Bedford North Lawrence High School and Mooresville High School.

Kawata looks to measure more than the risks. He also wants to understand how to protect players. The goal is to produce enough data to influence safety and recovery protocols for subconcussions in young players, similar to what exists for concussions. (A significant amount of that concussion data also comes from IU through its role as a co-leader of the CARE Consortium, the world’s largest longitudinal concussion study funded by the Department of Defense and NCAA.)

“That wholistic perspective is very rare,” Kawata said of his research. “You almost never see all three of these topics —– risk, protection, and mitigation and recovery — explored in the same lab.”

The study with high school football players is focused on quantifying risk, measuring the accumulated effect of subconcussive head impacts to understand when a player’s exposure has grown too great. The work uses advanced mouthguard technology with built-in sensors to collect data on every impact experienced by players. Ph.D. students from Kawata’s lab lead data collection and coordination efforts at each school in the study, including communicating with players, coaches and parents.

For the work on reducing risk, Kawata is leading a different study on head impacts in soccer, also funded under a $3 million award from the NIH, and serving as co-leader on a separate $6 million, multi-institute grant funded by the Department of Defense.

The first study focuses on the protective effect of omega-3 fatty acids. IU’s role in the other study focuses on the protective effect of increasing time intervals between exposure to impacts.

For the study on omega-3s, Kawata and collaborators split participants into two groups: an experimental group that is given the supplements and a control group that is not. Both groups are then asked to repeatedly head the ball, similar to a standard practice drill, after which they participate in cognitive tests, such as memory challenges, and physical measurements like blood tests or brain scans. Although the results of the impacts are imperceptible to players, they are enough to show up in blood biomarkers and MRIs.

For the time interval study, Kawata performs similar tests and measurements but varies participants’ time between impacts.

Participants in both studies include volunteers from community soccer teams and clubs across Indiana and neighboring states. Brain scans are performed by Kawata’s team members, including graduate students, who are all certified MRI technicians.

“We’re the only lab in the country set up to do this type of study,” Kawata said. “There are others who’ve studied fish oils in athletes during a sport season, but we’re the only one set up to do it all in a very tightly controlled environment.”

Kawata is also leading a number of studies on other factors that might reduce the risk of subconcussive head impacts, including ADHD status, cannabis use and hormone levels during menstruation. Early results suggest that players with ADHD may experience increased risks, requiring fewer blows to experience more serious side effects, and that cannabis may reduce the risks. The study on hormone levels, conducted with participants from the IU women’s water polo team, suggests that risk levels vary based on fluctuations in hormone levels.

Picturing the future of high-impact sports, Kawata evokes the idea of a “pitch count” in baseball — the total number of allowable pitches from a player in a game.

“In baseball, a player can throw 100 pitches and then they’re out, no matter how they feel,” he said. “But in football, there is literally no limit of how many hits a player can take. If we start to know the ceiling effect — if we know that a player will experience negative effects after X amount of hits based on blood biomarkers, for example — then that’s good because you can start to adjust practice drills to reduce exposure to new blows.”

In football, for example, a coach might replace live tackles with lower-impact drills.

“There are many, many factors influencing brain resiliency,” Kawata said. “But first we need the data to tease apart risk factors and protective factors. It’s only then that governing bodies in sports can adapt the best policies to protect every player.”