Zachary Sanderson knows it was a concussion that sidelined his high school coursework and ended his football career. More precisely, it was a series of concussions, culminating in one play that delivered three blows to his head.

Reporter Joe Zavala presented a detailed account of Sanderson's struggle to come back from that head injury in a story in Tuesday's paper. Unable to attend regular classes because of debilitating headaches and inability to concentrate, Sanderson eventually earned his GED, and now is enrolled part-time at Rogue Community College.

Not every high school football player sustains this kind of debilitating injury, and many apparently escape lasting effects from the repeated collisions that are part of the game. But there is increasing evidence of professional football players suffering chronic traumatic encephalopathy (CTE), which causes long-term impairment and, in some cases, leads to suicide.

A study of the brains of 111 deceased National Football League players recently showed 110 of them suffered from CTE.

The risk is clear, but the data is still too limited to make sweeping conclusions.  There is no conclusive evidence — yet — that high school football poses the same risk.

Still, participation in youth football programs is declining as parents steer their children into less violent sports. Coaches and trainers are working to make the game safer, but unclear how effective that will be.

In the meantime, parents and their children will have to weigh the risks as best they can, and make a difficult decision.