In the past several years, several hundred thousand helmet impacts and various levels of football, mostly intercollegiate, division 1-A, have been measured and documented for study. Virginia Tech has spearheaded the study. HITS. Helmet Impact Telemetry System. Google it. They're not just doing football, either, they're looking at ice hockey and lacrosse now too.
There is a HUGE database for study right now. What's been found, is that football players, indeed, have a higher incidence and risk of sustaining medically diagnosed concussions, than other sports. When you adjust the data, though, for frequency of contact, types, etc....(i.e. when you manipulate the data to make it comparable across sports, it's actually much more likely to sustain serious single head injury from a fall on the ice, hitting the back of your head, than ina football game. It's also arguable that football players don't tend to suffer concussion injuries at a frequency greater than hockey players, when you adjust for the numbers of players that actually sustain injuries, as compared to the numbers of players that actually play across sports.
Another thing to note, is that Chronic Traumatic Encephelopathy - which is what the NFL cases are about, is not definitively related to multiple concussions, and is very much different from sustaining a concussion, and is most certainly not related to sustaining a single concussion. It's not known what causes it, but it's been clearly identified in now three categories of people and higher incidence than in the general public. Professional football players, professional boxers, and military personnel exposed to blasts. The military has been studying the effects of shell shock, for a lot longer, than the same physiologic condition has been identified in professional athletes in boxing and football.
And that's the thing - CTE - is a physiologic condition, that a person is at risk of developing, if you play pro-football, are a pro-boxer, or are a soldier that has been exposed to significant shelling, your at a significantly higher risk than those that haven't..... but the same neurologic degenrative condition exists in people that have never been in any of those situations, playing footbal at any level, boxing, or a soldier. In two cases, direct blows to the head are related, in the third, there is no direct blow to the head, other than a sound/air pressure wave. Nobody can predict who's going to get CTE, and why. Many pro football players and pro boxers don't get it.
The other thing that has become clear with the data, is that which we all seem to know anyway - the greatest incidence in significant head injury/concussion comes with the smaller/faster players. The highest number of pretty violent head impacts occur among the big gusy at the line of scrimmage, but the highest incidence of medically diagnosed concussion is in the second and third levels of players away from scrimmage.
The most important thing that can be done to prevent concussion, is to teach proper body contact to protect the head in blocking and tackling.
I've advocated for years, that kids shouldn't be put in headgear or pads, playing the game, until high school. The easiest way to teach a kid proper body contact, to protect their head, and not use their gear and helmets as weapons, to hurt either themselves or others, is to have them play full contact with no headgear and no shoulder pads.
My opinion. I'm in the minority.
Football is not going away, what will happen with these lawsuits, is that the NFL ownership club, which is a 32 member club worth multiple billions of dollars, will have to open up those purse strings in a big way, to provide for the future lives of the gladiators, that are not just giving up their brains for their billions, but their knees, hips, shoulders, hearts, livers, kidneys......too.