Helmets on Board Sucks

[green03]

Problem is that helmets aren't necessarily preventing concussions as much as people naively assume. That should figure into the equation; can't think of a good analogy of some other safety equipment that doesn't address one of the major modes of injury from the same root cause. That's got to figure in the analysis of where/when it makes sense to wear. But also, some redesign of these things is probably overdue.

 

[USA190520]

i had a decal on a motorcycle helmet that read, " if you find this helmet with a head in it, call 911"

I think the reduction of fractured skulls and severe blunt force trauma are reduced, to say that helmets protect from concussions is silly. They turn what would be horrible into something less horrible... Nothing is fail safe,

Edited to say, damn it fastyacht!!

 

[Snaggletooth]

tiime to kicke tranning wheelles off and see wheare it goese........

 

[green03]

I think the reduction of fractured skulls and severe blunt force trauma are reduced, to say that helmets protect from concussions is silly. They turn what would be horrible into something less horrible... Nothing is fail safe,

Helmets protect against skull fractures, abrasions and lacerations. They do not prevent concussions. That is settled already.

OK, for sailing, as opposed to motorcycling, which scenario is more common? Wouldn't that factor in the discussion whether helmets are appropriate safety equipment or just make you "feel" safer?

 

[BobBill]

Maybe we are missing something?

 

[Lex Teredo]

Bullshit helmets don't prevent concussions. That's a fun sweeping generalization that the anti-football people are touting but I wouldn't ditch the football helmets just yet.

Helmets don't prevent *all* concussions would be an accurate statement. Concussions generally - though not always - come from a sudden acceleration / deceleration. (Same thing, physically speaking). The degree to which a helmet prevents or mitigates a concussion depends on the helmet and the impact. If the helmet crushes and brings the head to a more gradual stop (or slows a sudden acceleration, as in a boom whacking your head), it will tend to mitigate or prevent concussions. If it just functions as a rigid shell it won't help as much. Having a crush zone is important. Aaaaand there's also studies claiming bike and motorcycle helmets and the like don't crush, which is false. But there you go.

There's also the matter of preventing skull fractures and open head wounds. I think helmets are pretty effective there, although I'm sure there's a study to refute that too.

 

[BobBill]

Maybe, you really think about it, the helmet mentality is precisely what ails us, but that is another subject, isn't it, though it might underlie the issue?

 

[BobBill]

Fastyachts, not demeaning helmet use, but there is a mental disposition also; however, that is entirely grist for another thread. (Good that you had a helmet on the gourd!)

 

[House Salad]

What's a "Board Sucks"?

 

[MoeAlfa]

Bullshit helmets don't prevent concussions. That's a fun sweeping generalization that the anti-football people are touting but I wouldn't ditch the football helmets just yet.

Helmets don't prevent *all* concussions would be an accurate statement. Concussions generally - though not always - come from a sudden acceleration / deceleration. (Same thing, physically speaking). The degree to which a helmet prevents or mitigates a concussion depends on the helmet and the impact. If the helmet crushes and brings the head to a more gradual stop (or slows a sudden acceleration, as in a boom whacking your head), it will tend to mitigate or prevent concussions. If it just functions as a rigid shell it won't help as much. Having a crush zone is important. Aaaaand there's also studies claiming bike and motorcycle helmets and the like don't crush, which is false. But there you go.

There's also the matter of preventing skull fractures and open head wounds. I think helmets are pretty effective there, although I'm sure there's a study to refute that too.

The clinical data on this question are not very good or very clear. The best come from football and if there is an effect of helmets on concussion there, it doesn't seem very big. This may be because much of the acceleration-deceleration you mention is not linear, but rotational. Of course, there are no comparisons to no helmet. You are definitely right, however, about the prevention of skull fractures, which is why I wear a helmet every day on the bike. Skull fractures kill and kill fast.
Want to mitigate concussion? Maybe develop a fluid damping system of some kind. I don't think rigid helmets will ever do much for concussion.

 

[BobBill]

Water on the brain, fit for swabs of all persuasions...

 

[Suijin]

Anyone who has played hockey at a decently high level will tell you in no uncertain terms that helmets help prevent concussions. Slam your head on the ice without one, and then slam your head onto the ice with one. I don't need statistics to tell me that the helmet is helping to cushion the blow of impact and thus helping to protect against concussion.

I'll agree that helmets provide only so much protection. But it stands to reason that ANY protection which changes the acceleration/deceleration parameters is going to help to some degree.

The one concussion I've sustained was playing soccer in college in a head-to-head collision. I certain beyond doubt, based on my experience playing hockey with a helmet, that if I had been wearing a helmet during that encounter I would not have been concussed.

I feel slightly uncomfortable going at this topic with "it's just common sense" and throwing in some anecdotes as I'm usually a "show me the data" guy, but I think the biophysics of the matter is fairly straightforward.

 

[green03]

I think it's absolutely appropriate to ask "what are the common (head) injury scenarios in sailing" and then evaluate (and perhaps redesign) helmets on that basis. And I wouldn't be surprised if the answer depended on the type of boat and sailing.

The biophysics is fairly variable. If you sail an AC72 you can end up falling from a height of a multi-story building. That's different scenario from getting whacked by a boom nicely at head level, and then there are a number of scenarios where you might get hit by / thrown into things that have sharper corners. On the downside is the scenario of being under a capsized boat.

I think it's not simple "common sense" to simply wear any kind of helmet. A number of the boats I sail, I predict a bicycle helmet, to give one example, could actually be counterproductive. It rides so tall that it would actually allow the boom to contact it, whereas it would normally clear my head with a good margin...

Some other boats might benefit from a padded boom rather than a helmet, etc.; some have rather sharp or pointy hardware mounted in strategic places, in those cases, any kind of helmet, even a stiff padded leather cap would cut down on lacerations, and fracture protection might be more of a concern.

I think it's great, having a discussion on this, but my feeling is we are far from having solid recommendations one way or another, or even knowing what the real tradeoffs are.

And I think that even the assumption that sailing presents a common risk profile may be unwarranted.

 

[BobBill]

No argument from me...still, after 40 years before and behind the mast, my gourde has never been dinged, except by slightly closed hatch or low companion way.

Of course, I sail, not fly.

 

[JohnMB]

I'll counter your story about hockey players arguing that helmets prevent concussions. Looking back with the knowledge we have now, I know very specifically when I experienced concussions on the ice. With a helmet. Without even putting my head on the ice. Multiple times I saw stars and went dizzy. In other instances I had to take a knee. One time, I actually split my forehead open--the pressure was great enough right through the pads in the helmet. I had to skip the 2nd period. When I got back out on period 3 with stitches, I wasn't right. I know now that that was a concussion.

Maybe sometime lay out the maths to show how little the helmet can do for this.

By the way, I can't remember slamming my head on the ice even once in a hockey game. Not once. In 25 years.

the fact that you can get a concussion while wearing a helmet under a specific circumstance does not affect the question of whether wearing a helmet reduces the incidence of concussion under that particular circumstance, (e.g. hitting the ice with your head)

The key issue here is acceleration, if the helmet is designed to allow the head to compress the internal foam during a collision, that will reduced the acceleration during impact. I don't know is this is what hockey helmet are designed for, I suspect that they are primarily designed to prevent injuries due to the puck.

The math on this is far from simple, I know some of the people who worked on boxing injuries and how to model the way the pressure waves from impacts travel through soft tissue and bone, its a complex problem. But certainly reducing the maximum acceleration is a significant part of this.

The question of sailing headgear comes down to

-is there a significant risk which could be mitigated by headgear

-is the headgear comfortable enough to be worn on a regular basis,

-does the headgear create a significant reduction in risk

In most cases for sailing we are not at a point where helmets make much sense, in some cases they do make sense, who knows what the future holds, be we certainly shouldn't disparage anyone who feels more comfortable wearing protective headgear, unless it clearly increases he risk of injury for some reason, or anyone who chooses not to use protective headgear on a boat because they don't feel comfortable with it, unless they are taking an unnecessary risk by doing so.

it makes me wonder how long it took for construction worker to accept hard hats when they were introduced .

 

[MoeAlfa]

In the one prospective, randomized, controlled trial of headgear in sports that I was able to find (a very large study of rugby players), there was no significant effect of padded headgear on measures of brain injury <http://www.ncbi.nlm.nih.gov/pubmed/19127196>. PM me if you are interested and can't access the full text.

It is worth noting that one's subjective impression of impact with and without a helmet is derived from effects on the skin, bone, sinus linings, meninges, large blood vessels, etc., since the brain, which alone among the contents of the head is subject to injury from deceleration in the range we're talking about, has no sensation.

Historically, "common sense" has been a very unreliable guide in clinical matters.

 

[JohnMB]

Think of it this way: no helmet can be much more than 1" thick or it becomes a problem to wear. The distance over which the acceleration can be modified is one inch. That severely restricts the effectiveness. Just simple F=MA with S=1/2 AT^2 on that.

I'm not disagreeing that helmets are not designed to prevent concussion, or even about how effective they are,

If we apply F=MA and s=1/2at^2, (actually I would go with s=(vi-vf)/(2a) (and i agree that constant acceleration is a reasonable assumption for this even though both know that's not what we will see). But the change in s between no-helmet (where s is effectively determined by the thickness of flesh over the skull and the stiffness of the skull) and helmet (where S is determined at least in part by the compression behavior of the foam) can be substantial.

If the foam is deformed 1/2" in the impact vs say a stopping distance of 1/4" with no helmet then by doubling the stopping distance you 1/2 the force. It seems unlikely that this would not have an effect on marginal cases for concussion. Obviously it may be that only a very small fraction of the total cases are marginal, and that most incidents exceed maximum impact forces that a helmet can mitigate, espcially when the helmet is not specifically designed to prevent concussion.

 

[Suijin]

I'll counter your story about hockey players arguing that helmets prevent concussions. Looking back with the knowledge we have now, I know very specifically when I experienced concussions on the ice. With a helmet. Without even putting my head on the ice. Multiple times I saw stars and went dizzy. In other instances I had to take a knee. One time, I actually split my forehead open--the pressure was great enough right through the pads in the helmet. I had to skip the 2nd period. When I got back out on period 3 with stitches, I wasn't right. I know now that that was a concussion.

Maybe sometime lay out the maths to show how little the helmet can do for this.

By the way, I can't remember slamming my head on the ice even once in a hockey game. Not once. In 25 years.

Well the obvious question is what the outcome would have been in those multiple times if you'd not been wearing a helmet. Like I said, I don't for a moment think that helmets categorically prevent concussions, but they are a first line of defense.

As far as never slamming your head on the ice in 25 years of playing hockey, well that's anecdotal evidence (just like mine ). Is your inference that it never happens because it never happened to you and that I'm a liar, or that I must have been a bad player for it to happen to me? lol

 

[Dabnis]

People who ride motorcycles without helmets are known as "Donor-Cycles". I would have been dead in '79 except for the Bell helmet that cracked when my head hit the asphalt after flying a hundred feet through the air when the Ford Capri took out the BMW 75/6 that I was astride on my way home for lunch. Shattered wrist was the only major damage.

"Been there, done that, but in the dirt:

http://s641.photobucket.com/user/ptnt11085/media/Motorcycles/100_8159_zps3ec79459.jpg.html?sort=3&o=5

Sailed in & out of San Francisco Bay for many years, however didn't do any organized racing. Surprising how hard a boom can be, or

the deck when the jib is trying to beat you to death. Looking back on it, a light helmet would have felt good on a few occasions.

Unlike motorcycles, I doubt that helmets will be mandatory for recreational, private sailing. "To each his own"

Paul T

 

[JohnMB]

Think of it this way: no helmet can be much more than 1" thick or it becomes a problem to wear. The distance over which the acceleration can be modified is one inch. That severely restricts the effectiveness. Just simple F=MA with S=1/2 AT^2 on that.

I'm not disagreeing that helmets are not designed to prevent concussion, or even about how effective they are,

If we apply F=MA and s=1/2at^2, (actually I would go with s=(vi^2-vf^2)/(2a) (and i agree that constant acceleration is a reasonable assumption for this even though both know that's not what we will see). But the change in s between no-helmet (where s is effectively determined by the thickness of flesh over the skull and the stiffness of the skull) and helmet (where S is determined at least in part by the compression behavior of the foam) can be substantial.

If the foam is deformed 1/2" in the impact vs say a stopping distance of 1/4" with no helmet then by doubling the stopping distance you 1/2 the force. It seems unlikely that this would not have an effect on marginal cases for concussion. Obviously it may be that only a very small fraction of the total cases are marginal, and that most incidents exceed maximum impact forces that a helmet can mitigate, espcially when the helmet is not specifically designed to prevent concussion.

minor correction.