Head injuries - How often have you seen them?

[skategeek]

Agnes:  Is there any test data published on the ice halo?  I keep looking and hoping to discover some.

Buried somewhere on their web site there's a statement that they were tested and met certain standards for hockey (front, back and side impacts, I think but I'm not positive), but no actual data or citation.  Last time I went back looking for it I had trouble even finding that statement (though I think it's still there somewhere).

[AgnesNitt]

To my knowledge, and I just checked, there are no ASTM certification for figure skating helmets.

The closest thing is a roller skating helmet.

I actually contacted the Chair of ASTM with the question about figure skating helmets and never got an answer (natch),

ASTM covers speed skating, hockey, roller skating, lacrosse, skateboarding, trick (!) roller skating, in-line skating, and probably stuff I missed. But they don't even mention why they don't cover figure skating.

So without ASTM standards it's not possible what to say is good enough.

Thus, the ICE HALO people have to say "This product is designed to reduce the pain of a fall. Neither the manufacturer nor retailers are liable for injuries incurred while wearing this product, nor for injuries incurred while wearing this product incorrectly." Because lacking international standards there's nothing that can be determined.

They used to have some data on their website, so I guess a lawyer made them get rid of it.

I have one, and the foam is about the thickness and density of my old riding helmets, so I'm okay with it.

Given that the international standards association doesn't give a damn about figure skaters, we're all pretty much forced to make a decision on our own.

Foam thick as my riding helmet is my personal standard for now.

[riley876]

In my mind, all the standards are so poor (i.e. unsuitable for the job), that it's of no great loss to not have a specific standard.   e.g. none of the standards specify anything about medium speed impacts.   

But if I had to pick the least worst standard to use, the skateboarding/trick-roller-skating F1492 is probably closest to the task.   F1492 at least specifies a low test line at the rear.   And skate helmets aren't restrictive visually at all, unlike hockey helmets.   You can also get EPP variants of F1492 helmets which are multi-hit rated,  and probably a bit better at lower speed hits than the rock hard polystyrene commonly employed in bike helmets.

If I only ice skated, I'd probably just make my own ice-halo style headband.   Trivial sewing project.  But I use a hard shell skate style helmet for outdoor skating anyway, and I don't actually give a damn if I look like a very lost derby girl on the ice anyway

[tstop4me]

Thanks JSHalo.  I am now cleared to drive, go back to work and have returned to the ice.  After three public sessions things such as remembering the steps to simple ice dances that I previously knew my heart, and skills such as power pulls, inside 3s, etc. are slowly coming back.  I told my coach that I'd be in touch once I get to the point where lessons will not be a waste of time.  I'm wearing a Bern "Watts" skateboard helmet and am still researching the topic of protective head gear.  An individual commenting on one of my blog spot posts has tipped me towards a headband made by Force Field.  Unlike the Ice Halo and the Crashe Middie, the Force Field headband appears to comply with an ASMT standard (F 1045) recommended for hockey helmets.  Those interested can read more here:  http://www.forcefieldheadbands.com/testdata.html  At $15 to $20, depending on the model, these headbands seem reasonably priced and I plan to order one to see if it will fit within my existing Bern helmet.  If not I may wear the headband without the helmet--provided I can convince myself that I'll have adequate protection.  I can't afford another blow to the head at this point.   

Note that Virginia Tech recently tested hockey helmets (that meet current HECC standards) for protection against concussions.  Their results indicate that almost all fared poorly.  The full test report can be downloaded for free here:  http://link.springer.com/article/10.1007/s10439-015-1278-7 .  A summary can be found here: http://www.beam.vt.edu/helmet/helmets_hockey.php.   Bauer responded that their helmets do meet current standards, but make no claims with respect to protection against concussions.  The current standards are focussed on protection against skull fractures.  Here's an informative summary video with interviews with representatives from Virginia Tech, Bauer, and HECC:  http://espn.go.com/espn/otl/story/_/id/12564082/virginia-tech-study-hockey-helmets-finds-many-unsafe.

[riley876]

Hockey helmets are always going to struggle, because the foam is too thin.

[beginner skater]

Hmm, thinking I should think about head protection. Agnes Nitt, I think at one stage you put gel pads in your hat? But have changed to an Ice Halo? I was wondering what you think of the two?


I am wondering about whether to make a head band with akton pads, which I already have, or import an Ice Halo to the UK. I'm not jumping, so it's freak falls, being knocked over, or losing my balance whilst attempting 3 turns that I need protection for. Can anyone advise?

[jjane45]

I am wondering about whether to make a head band with akton pads...

That's what I do. A band of akton pads around my head inside a winter hat.
I once owned an furry ice halo but it was a poor fit for my head and felt way too hot.

[beginner skater]

How do you attach the band, both the ends to each other, and to the hat? I quite fancy the look of the furry ice halos, but feel it could look odd if I had to skate sleeveless because I was so warm  And I dont fancy the price especially with shipping & import tax  added

[jjane45]

How do you attach the band, both the ends to each other, and to the hat?

I sew a very simple pocket and place the band inside. (previously I even used leftover akton pad pieces to put together the head band, each piece had its own cell in the pocket)
As long as pocket and hat both fits your head snugly, there is no need to attach them together. Makes cleaning easy.  Ear flap hats are the most secure for me. Skate safe and have fun

[riley876]

Interview with Marie-France Dubreuil, Canadian Ice Dancer & Coach of Papadakis & Cizeron

https://www.youtube.com/watch?v=7rMoRDEvdio

She talks about Papadakis' concussion (@ 11:30 ish), and her own, from which she said she had symptoms (vertigo mainly) for *seven* years.

[emitche]

Thanks for sharing.

[dlbritton]

Last night I was showing my Crasche to another skater and she commented that she got a bad concussion skating but all she remembers is waking up in the CT scanner at the hospital. Now that has to be a disturbing experience.

[Query]

Last night I was showing my Crasche to another skater and she commented that she got a bad concussion skating but all she remembers is waking up in the CT scanner at the hospital. Now that has to be a disturbing experience.

I don't know if your friend had anesthesia before the CT scan, I had the same problem after a bike accident. I woke post-surgery with no memory from after starting the bike ride. None of those memories ever returned. Eventually I spoke to an EMT who remembered talking to me when they picked me up, and remembered where I had arranged to safely place my bike. (Though it proved too damaged to repair.)

As I've mentioned before, anesthesia for major surgery typically includes drugs which eliminate short term memory, so you won't remember the pain. You can specifically request that they leave this out. After that experience, I will.

The point being, it isn't always the concussion that makes you forget.

[riley876]

As I've mentioned before, anesthesia for major surgery typically includes drugs which eliminate short term memory, so you won't remember the pain. You can specifically request that they leave this out. After that experience, I will.

Benzodiazepines are apparently particularly bad for this.  Of which Midazolam (aka Versed) is the usual.   

And flunitrazepam (a.k.a. Rohypnol) is a benzo that's often used for "drug facilitated sexual assault".    If that doesn't scare one away from benzos,  nothing will!

[skategeek]

Reviving this thread... here's a couple of articles about some recent research on concussion prevention.  I'm not sure yet what I think of this, but it's an interesting approach.  At least it's acknowledging that helmets don't do much for concussion prevention.

http://www.si.com/edge/2016/06/15/concussion-prevention-technology-qcollar-neck-wearable-football-hockey
http://www.upi.com/Health_News/2016/06/15/Compression-collar-may-lower-effects-of-head-collisions-in-sports/3371466017594/

[riley876]

Very interesting.  Cheers.

Maybe it's an effective add-on, but I don't think they're advocating it instead of helmets?

[skategeek]

I don't think so, since helmets prevent/reduce other sorts of of injuries.  I assume it's an additional protection.  (On the face of it, the idea of doing something that alters blood flow in the brain gives me the willies.  But I assume they know what they're doing...)

[alan]

Only way is to wear a sports helmet, period. Even that only reduces the odds of a concussion, but does not give a guarantee.

[AgnesNitt]

Two words: Contrecoup.

Your brain bangs around on the inside of your skull. This will happen if you're wearing a helmet or not. The helmet may help, but helmets are mostly to reduce coup injuries.

The problem with helmets is that they encourage people to skate harder and faster when they don't have the skills to stop and thus actually are going faster when they hit. Also,(my belief( is that helmeted skater run into more people and hurt them while they walk away.

[riley876]

Three more words:  Newton's Second Law.

Force = Mass * Acceleration.

i.e. if you can reduce the (de)acceleration, you proportionally reduce the forces (that lead to both coup and contracoup injuries).   i.e. increase the impact distance (i.e. the distance that the foam compresses) to increase the impact time, to reduce the acceleration, (given that the overall velocity change is fixed)

i.e. Acceleration = ChangeInVelocity / TimeThatChangeTakes   (to put it in non calculus terms)

Saying that properly designed helmets don't help is flying against basic physics.   And is a tautology anyway.

Sadly, most standards approved hard foam helmets aren't properly designed for the range of impacts you'd expect from figure skating.   Acid test: if the foam doesn't compress significantly during the impact, then it's worthless.    Soft foam helmets like Ice Halos and hockey skates are better.  At least their foam WILL compress some,  but they're typically too thin to be really protective for all but the lightest hits.

[Query]

It isn't necessarily true that force is ALL that matters in how much damage occurs to the brain.

To some extant, energy absorbed could be important, because that might affect the total brain deformation. I wonder if any helmets absorb much energy.

Just a thought. Obviously, I agree that reducing force is a good thing.

I'd love to know if soccer and volleyball players get many concussions.

And whether head injuries are less serious on sand-foundation rinks than concrete-foundation rinks, because the rink surface may deform to some extant too. They often say that jumping feels different depending on the foundation. The coldness/hardness of the ice might matter too.

[riley876]

To some extant, energy absorbed could be important, because that might affect the total brain deformation. I wonder if any helmets absorb much energy.

Very little.  If you want to quantify it:  Work (i.e. Energy) = Force * Distance.   Where the distance is the amount of foam compression.   But it's not about energy.   Compare with the kinetic energy: E(k)=1/2mv².   Where v really is delta V.   Which is going to be the same regardless of if the impact is on concrete, or a 3 meter deep foam pit.    Either way you go from lotsa velocity to zero velocity.  The energy is the same.  What matters is more how quickly it happens.   Most of the energy in the hit is transferred to the ground as a momentum exchange (like billiard balls).  Which includes all your body's energy/momentum too.

I suspect there's a limit, below which forces to the brain are entirely benign.   Similar concept to applying sub-fracture forces to a bone. 

There's a couple of accepted measures of damage,  once is called HIC (head injury criteria) and another called the Gadd Severity Index.   Both are similar, essentially the area under an acceleration-vs-time graph of the impact (with slightly different exponents and scaling factors).   They both infer that you can stand a short hard force better than a longer similarily hard force.    They both infer that if you spread your impact out (e.g. by using a crushable helmet) then the severity is less, even though the impact is longer, because the force is proportionally less.  The exponents in the indexes make this a winning proposition.

[riley876]

And whether head injuries are less serious on sand-foundation rinks than concrete-foundation rinks, because the rink surface may deform to some extant too. They often say that jumping feels different depending on the foundation

Don't know, but I've fallen onto a plastic tile floor in such a way that my eyes were nearly at floor level.  I swear when I hit I saw an impact wave spread outwards from my location, like ripples on a pond.   Would not surprise me if that happens on ice too.   A few mm of deformation would definitively help.

[Query]

But it's not about energy... Either way you go from lotsa velocity to zero velocity.

OK, I said things wrong.

The energy from head motion can be absorbed in the skull and brain - or in the helmet. If none is absorbed by the helmet, the head (and helmet) will rebound more off the ice, at about the same speed, so the final velocity is not zero, so you get a larger velocity change. The force on the outside of the skull is the same, but it lasts twice as long, and can do more damage. Inside the head, depending on the relative timing of the rebound and the brain collision(s), you either get a larger velocity change and force on the brain, or more collisions of the brain with the skull. Either way, you get more damage.

If you see a numeric model of head damage that doesn't take head rebound into effect, it is obviously incorrect.

(BTW, an energy absorbing helmet would also reduce whiplash, because the soft body probably absorbs more energy and rebounds less than the more rigid head.)

An energy absorbing helmet can be much less thick to cushion the collision the same amount. Energy absorption should be a very important component of helmet design.

In terms of physics, it's the difference between a mostly elastic collision and a non-elastic collision. The more elastic collision can do much more damage to the structure of the colliding objects, because of the larger delta V.

I believe this is part of why bicycle and climbing helmets often use a crush-able foam - though such helmets are only good for one collision. And why construction and caving helmets often use suspension systems, which absorb energy by permanently stretching a strap. But they can't take many collisions either.

It's also part of why cars are designed to absorb collision energy in their front ends. The zone of the most severe damage includes the front end, but doesn't extend into the passenger compartment. And you get less rebound if the vehicles stick together. (But, yes, , cars can't take many collisions either, without substantial repair.)

I believe that skating helmets should be designed to take multiple falls (and hits, for hockey players), because most skaters take multiple falls (and hits). But you need a helmet that is much thicker to meet that requirement, because the obvious ways to design such a helmet absorb little energy.

I'm not sure if you can design an energy absorbing helmet that can take multiple collisions. An elastic closed cell foam absorbs very little energy, because the air compresses and expands outwards again almost adiabatically (without heat loss), and without structural or chemical change, after the collision. But crush-able foam and permanently stretched straps would be damaged by the collision, and lose future effectiveness. Do you know of an energy absorbing material that isn't damaged?

[riley876]

Do you know of an energy absorbing material that isn't damaged?

Supposedly this is the claim to fame of the viscoelastic polyurethanes (D3O et al).   Supposedly they direct it sideways.   But I don't think they're right for helmets because they don't compress much.  i.e. still a sharp deceleration with high forces.   They're great at spreading the load to a large area,  but that's a secondary concern with helmets (and something a hard plastic shell is perfectly capable of anyway).

I'm convinced too that permanently deformable materials are better than 100% elastic materials, simply because they exhibit half the impact duration at the same peak forces.   The elastic materials push back for the second half of the impact.  So yes, I guess this is an energy storage issue,  but deformable materials solve it completely, so I don't see what extra fancy materials could do?   

Perhaps a deformable material that slowly reinflates after an impact so you don't have to buy a new one,  but personally I don't hit my head often enough for helmet replacement to be a problem.

My absolute favorite material is a closed cell floral foam,  largely because it's totally deformable, to the point where the impact force vs time curve is nearly a flat line.   But sadly it's too fragile for use in a practical helmet.   Maybe a thin epoxy over it would help though.

OTOH, a really beneficial technological advance would be a velocity sensitive foam.  i.e.  to give full compression at any speed of impact.   That would greatly reduce the needed thickness (or alternatively improve the protection).   Air bag systems would be even better, but I doubt the triggering issue is solvable for figure skating.