Hitting someone whose head is down is fine, as long as you don't hit 
them in the head.  Hit them in the head, and it doesn't matter whether 
it was down or not.

There is also a limit to how much helmet technology can do.  Concussions 
are caused by the acceleration and deceleration of the brain within the 
cranium.  To reduce that, a helmet needs to dissipate the energy of a 
hit into something other than motion of the head.  From what I've read, 
the medical researchers a fairly pessimistic about how much advancement 
there is to make on that.  Momentum, after all, has to be conserved, so 
something would have to move along an axis orthogonal (or at least 
significantly orthogonal) to the direction of the blow.  The sport where 
there has been the most advancement in this is auto racing.  The reason 
that it's been successful is that they are okay with pieces of the car 
flying in every direction.  Every one of those pieces is carrying 
momentum that is not transmitted to the main body of the car, and thus 
the driver.  That's why crashes can be so spectacular and yet the driver 
walks away mostly unhurt: the car is specifically designed to 
disintegrate in those conditions.

For some pretty good reasons, we are not okay with a hockey helmet 
breaking into dozens of pieces whenever someone takes a blow to the 
head.  That has the advantage of increasing its ability to prevent cuts 
and to protect someone's head when they fall to the ice.  Unfortunately, 
it drastically reduces the number of ways you can improve its protection 
against concussions.  Mouthguards help by reducing the acceleration of 
the initial blow, but don't really do anything to reduce the 
deceleration on the other end.  The same is true of wearing the helmet 
properly.  So, that can reduce concussions.  However, a lot of the blows 
now are hard enough that the deceleration by itself is problematic.  
It's the same as a whiplash injury in a car crash, and is the reason for 
other safety devices in auto racing which also aren't transferable to 
hockey because of the greater need for neck mobility in play.

That is what leaves us with the need to dissipate the momentum of the 
blow, rather than just reducing the initial acceleration.  The basic 
idea of a helmet is successful at the latter, but not very good at the 
former.  Increasing the padding is sufficiently inefficient at that that 
we've pretty much maxed out that approach.  There has been progress with 
goalies' helmets, and the way that they are now shaped to deflect 
incoming pucks rather than to take them flush.  I'm not sure what a good 
way to deflect shoulders, elbows and chests is, particularly since they 
are likely to come from a much greater variety of angles; a helmet 
designed to deflect blows from one direction is likely to reduce the 
deflection from others.

What it will take is some method through which there is some mass in the 
helmet that gets accelerated in a direction other than the axis of 
impact and does not leave the helmet.  It also can't simply transmit the 
momentum back to the head when it comes to a stop against whatever 
barrier prevents its ejection unless it spreads that secondary impact 
significantly over time.  The closer it comes to accelerating on an axis 
perpendicular to that of the impact, the better.  It has to be able to 
do this regardless of the axis of impact.

I'm dubious that this will end up being the answer.

On 3/28/2011 3:19 PM, Matt Sullivan wrote:
> I certainly don't dispute that a hit to the head is illegal, but unfortunately
> it becomes such a subjective call for the refs to make.  Your original email
> made it sound like a person shouldn't hit another player if their head is down,
> and I still disagree with that.  
>
> I'd like to know what Bauer, Easton, CCM, Itech and Reebok are doing to advanced
> helmet technology.  It seems like the design of the helmet hasn't changed in 20+
> years.  Also a factor on head injuries isn't just contact but the improper fit
> of helmets, facemasks and mouthgaurds.  Watching yesterday's MW regional I was
> surprised to see a bunch of masks hanging down an inch or more lower than they
> should.  There's lots we can do to lower head injuries without taking the
> physicality out of hockey.
>   Matt Sullivan
> Group Insurance Specialist
> The Sullivan Agency, LTD.
> www.sullivanagency.com
>
>
> University of Minnesota Duluth, 1998
> BU-LL-DO-G-S GOOOOO Bulldogs!!!!
>
>
>
>
> ________________________________
> From: J. Michael Neal<[log in to unmask]>
> To: [log in to unmask]
> Sent: Mon, March 28, 2011 10:25:06 AM
> Subject: Re: observations of a weekend couch potato
>
> On 3/28/2011 9:32 AM, Matt Sullivan wrote:
>> Since when can't you hit a player when their head is down???
> Since we started learning just how damaging concussions are.  If you derive
> enjoyment from watching people suffer brain damage, I can't stop you.  I,
> however, have been opting out pretty rapidly.  I can't watch NFL football
> anymore, and I'm losing patience with the NHL.  Fortunately, I discovered that
> women's hockey is a great game, with a much lower injury rate.
>
> Given how large and how fast the players are today, the only way you're going to
> stop the escalating rate of concussions is to prevent hits to the head.  It
> doesn't matter whether the checked player's head is up or down.  Either
> eliminate those hits, or you'll see a continuing parade of players to the
> hospital.  The research being done on concussions in sports is frightening if
> you care about the players' well being, particularly the evidence that an
> accumulation of blows that do not produce concussion symptoms can do serious
> long term damage.
>
>