Football players as young as 7 years old sustained an average of 107 hits per player during a single season, the first study to analyze head impact exposure in youth football shows.

The hardest of the hits came during practice, not games.

The study, published in the Annals of Biomedical Engineering, analyzed just seven kids, but the findings helped secure funding for a much larger study announced this week. Head impact exposure in high school and college athletes has been well documented. While this study suggests that youth football players sustain less frequent hits, the level of acceleration can reach the same level measured in adults — which is high enough to cause concussions.

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"This new study for 2012 allows for a dramatically increased sample size [approximately 50,000 head impacts will likely be recorded] and head exposure mapping for all age groups,” said Stefan Duma, department head of the Virginia Tech – Wake Forest University School of Biomedical Engineering and Sciences, which directs the project.

To study the biomechanics of impacts, researchers will use medical imaging protocols combined with brain computer modeling.

The initial study also led to the development of the National Impact Database, containing the first safety rating system for adult football helmets.

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Between 1991 and 2006, participation in one popular youth organization, Pop Warner Football, almost doubled from about 130,000 players to 260,000 players. No need for coaches to wait for further results to start modifying practice, authors of the initial study suggest. Avoiding replicating game situations in practice could significantly reduce head impacts, they say.

Photo Credit: Corbis