The damage done to a football player’s brain after a full career on the field may not only be debilitating — it could be deadly. It is why so much has been invested in concussion research and awareness over the past five years in particular.

But a new study looks at the toll a single season of hits can have on a teenager’s brain.

“We saw changes in young players’ brains on both structural and functional imaging after a single season of football,” said one researcher.

“It’s important to understand the potential changes occurring in the brain related to youth contact sports,” said Elizabeth Moody Davenport, Ph.D., a postdoctoral researcher at UT Southwestern Medical Center in Dallas, Texas, in a media release. “We know some professional football players suffer from a serious condition called chronic traumatic encephalopathy, or CTE. We are attempting to find out when and how that process starts, so that we can keep sports a healthy activity for millions of children and adolescents.”

The study monitored 24 players from a high school football team in North Carolina. Each player wore a helmet outfitted with technology called the Head Impact Telemetry System (HITS) during all practices and games. The helmets are lined with six accelerometers, or sensors, that measure the magnitude, location, and direction of a hit. The data is then uploaded to a computer for analysis.

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Not one of the 24 players was diagnosed with a concussion during the study. Still, Davenport said, “We saw changes in these young players’ brains on both structural and functional imaging after a single season of football.” Players with greater head impact exposure saw the most change — in a measure of the white matter deeper in the brain, and the marker for a type of distress signal within the brain.

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Davenport said similar studies are being conducted this fall. A consortium has been formed to continue the brain imaging research in youth contact sports across the country.

“Without a larger population that is closely followed in a longitudinal study, it is difficult to know the long-term effects of these changes,” she said. “We don’t know if the brain’s developmental trajectory is altered, or if the off-season time allows for the brain to return to normal.”