I was a high school soccer player who actively avoided football, but not because of head injury worries. I was lucky.

I'm also an amateur boxer who VERY much limits sparring, specifically because by the time I started boxing, CTE was becoming known.

If you take a few punches to the head, you have to a moron not to understand that this isn't good in the short term. The drunk guys in the gym who can't finish sentences - or Muhammad Ali - are evidence of the long term affects.

The reason I highlighted that line is that another part of the problem of CTE is that eveyone reacts differently, and you won't know if you're unlucky and how unlucky until it is too late.

Anecdotally it takes about 10 years for such head trauma to really start to show. Maybe that will be medically corroborated at some point.