That said, in reading about this for the last decade or so when it became a top news item, its become apparent that most brain injury news stories don't report on them very well and lump 2 drastically different kinds of brain injury into the same bucket. Concussions and CTE. The former is caused by a single traumatic event that can leave the brain damaged after it. The latter is probably a repetitive injury, lots of small events that add up to brain damage.
Gridiron football has the opportunity for both. Big shots on open field runners frequently lead to concussions, but for CTE the most dangerous position may be offensive linemen who infrequently take those high speed impacts that get so much coverage. Instead on every play they are taking repeated small blows to the head.
This is how soccer gets lumped in. There is at least circumstantial evidence that the arial game in soccer and potentially even header practice can lead to CTE at fairly high incidence rates. Given the lack of studies its unclear what the level of danger is.
Hockey on the other hand has the opposite danger. Repeated small head hits are rarer than in football but the incidence of traumatic concussion causing hits is similar if not higher.
American football is the first sport to have major studies around brain injury and those are fairly early days. As the other sports have more studies, and as the studies get more data, I suspect we will find that all contact sports put you at risk of brain injury and that football and rugby have higher incidence of CTE than the others. But thats just guess work right now.
Football on the other hand... it’s pretty much impossible to take the CTE risk away without ending up with another sport (rugby, Aussie rules, whatever).
IMO the long term viability of US football is not good.
Why anyone would want to mess with the brain is beyond me.
After all, handling the ball (referring to both arms and hands) is already banned and banning the head would just neatly slot in there and could use the same rules. (I.e. just add “or head” to this sentence in the rules of the game “Handling the ball involves a deliberate act of a player making contact with the ball with his hand or arm.”).
(If you ban headers for health reasons you should, however, probably also ban the goalkeeper from doing headers, even though the goalkeeper is allowed to handle the ball under certain circumstances.)
I do not know what other rule changes would be necessary, but, as I said, I wouldn’t expect the game to be radically different and unrecognisable. (Are there implications for corners and free kicks would be my main question. I could imagine that those are suddenly worth less if headers are disallowed, since in those situations the defenders have time to get in place and space and – as a direct consequence – time are consequently tight. Always having to get the ball to the ground or at least on a level where you can kick it somehow will slow the game down, giving defenders more time to react.) But I also know that soccer (associations, clubs, fans) can be very conservative …
A desperate false equivalence to defend the right to exist of a brutal sport that doesn't belong to a modern compassionate world.