Football players receive a tremendous number of head impacts over the course of the season. Most of these hits aren’t serious enough to cause a significant injury. With media attention on brain injuries in football at a high level, concern exists about the cumulative effect of these blows, though.

How long, then, does it take for a player’s brain to fully return to normal after a season of these head impacts?

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Changes in the brain’s white matter

A study published this month in Plos One suggests that the usual six-month offseason might not be enough.

Jeffrey Bazarian and his team reviewed diffusion tensor imaging studies of the brains of 10 college football players and five non-athletes before and after a football season. They also analyzed the brains after a six-month period of no-contact rest.

The 10 football players absorbed anywhere from 431 to 1850 head impacts over the course of the season. None of the football players suffered a concussion during that season.

The researchers found changes in the white matter of players’ brains after the season. The magnitude of these white matter changes correlated with the number of head impacts each player had received over the course of the season. More worrisome was the finding that these white matter changes – roughly equal to the findings after a mild brain injury – usually persisted after the six-month rest period.

Youth football game

Are these findings worrisome?

The good news is that the changes on these brain studies did not mean the players exhibited any symptoms. Their true significance is unclear. They could be silent findings, or they could represent changes in brains more susceptible to head impacts and concussions.

It’s at least worth asking if six months is long enough of an off-season. The 10 players in the study had no contact during those six months.  Most football teams have spring practices or off-season training that shortens their true rest periods.

Also read:
Are “hit counts” headed to football?
Would noncontact practices make football safer?

Where do we go from here?

There is clearly much more we need to learn from studies like this one. Over time, I expect we will hear more calls for change. Are hit counts and keeping players below a threshold number of hits on the horizon? Will teams and leagues eliminate contact from practices one or more days each week? Will more youth organizations push for limiting contact for players under the age of 12 or 14?

Concussed football player on the bench

Jeffrey J. Bazarian JJ, Zhu T, Zhong J, Janigro D, Rozen E, Roberts A, Javien H, Merchant-Borna K, Abar B, Blackman EG. Persistent, Long-term Cerebral White Matter Changes after Sports-Related Repetitive Head Impacts. Plos One. April 2014. Volume 9. Issue 4.