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More than 2 million children between the ages of 6-14 play tackle football

Exposure to tackle football can change brain structure

CNN  — 

Last year, according to USA Football, over two million children between the ages of 6-14 participated in tackle football. For many parents, the worry has been over concussions. But a new study finds there could be cause for concern over the cumulative impact of repetitive or sub-concussive hits on the brains of young players when out on the field.

The study, published in this month’s edition of the journal Radiology, adds to the growing debate about whether or not children should be allowed to play contact sports.

Despite the studys small size, tracking only 25 youth football players between the ages of 8-13 over the course of just one season, it is the first research to look at this age group and find players still experienced structural changes to the white matter in their brain despite having no concussion diagnosis during the season.

Microscopic changes with big implications

“These are not the type of changes you see with the naked eye - so they may or not mean anything ,” cautioned Joel Stitzel, Professor of biomedical engineering at Wake Forest School of Medicine and one of the authors of the study. Rather, Stitzel said that these findings indicate areas that need further study as well as pinpoint the right areas to be looking at for research.

Previous studies have shown similar findings in high school and college players, but seeing this in such an early age group made Dr. Robert Cantu, medical director of the Concussion Legacy Foundation, pause. “I don’t want to be alarmist….but finding this in youth players is particularly concerning,” said Cantu, who was not involved in the study.

Dr. Christopher Giza, director of UCLA’s Steve Tisch BrainSPORT Program, cautioned that the findings should be taken with a grain of salt because of the small sample size. Giza also did not participate in the study.

What is white matter?

When most people think of the brain they typically envision gray matter - the dark folded tissue that makes up the brain. This is where most of the neurons, or nerve cells, in the brain reside. However, to help those neurons efficiently communicate with one another, the brain relies on the white matter underneath, connecting various neurons and parts of the brain to one another.

White matter is composed of millions of nerve fibers called axons and by using a sophisticated form of brain-scanning MRI technique, scientists are able to measure the movement of water molecules in the brain and along the axons. A healthy brain has fairly uniform water movement whereas more random water movement has been linked to brain abnormalities in previous studies. This movement has been associated with longer term concussive symptoms, such as headaches and dizziness, explained Stitzel.

In this study, the researchers found a significant association between increased head impacts and more random water movement in certain regions of white matter.

Stitzel pointed out that the changes in the studied players did not appear to be associated with any symptoms of concussion.

However, it’s also not clear if the impact to the brain is permanent.

” Whether the brain is irreversibly injured, we don’t know, because further studies need to be done. This is a pilot study and it cries out to be done in a longitudinal way to be followed over years. So these changes recover? Do these changes get worse?, ” said Cantu.

Young players particularly vulnerable

What concerns Cantu so much is that the brain at this age range is particularly vulnerable, pointing out that the necks of players in this age group are not quite as strong as high school and college players. “Youngsters at this age aren’t as fast and big, so the collisions aren’t as spectacular, but their necks are very weak and that creates bobble head doll effect,” said Cantu. Despite their lack of speed, Cantu said younger players can collide with just as much impact.

And while brain plasticity is on the side of youngsters, Cantu added “Young brains are in the process of making the connections between the ages of 9-12, in terms of giving your intellect, your mood, and also, behavior, whether you have a short fuse or not - so it’s a particular concern to be injuring a brain at the time these final connections are being made.”

Cantu advocates that children under the age of 14 should avoid tackle football, out of concern for their brain development.

Changing the game

In recent years, leagues such as Pop Warner and USA Football have already implemented rule and practice changes to limit contact exposure.

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    “We all should be looking towards minimizing impact risk in kids, including (but not limited to): having good protective equipment, using careful training protocols that minimize unnecessary impacts, penalizing illegal or inappropriate plays, avoiding poor playing techniques, providing meaningful concussion/brain health education and properly and promptly diagnosing and treating concussions,” said Giza.

    Stitzel agrees and hopes this, and future studies, can help better inform parents, coaches, and players. “I think our general view is this is the type of work that will inform better decision making…the sort of thing that is intending not to hurt, but ultimately save and make the sport safer. ”