Debating on the protective effect of headgears

[csrichie]

I've read websites debating on the protective effect of head gear, with some suggesting that they only offers protection against bruises.

However, I don't believe that this is the case. Some people argue based on the fact that same amount of total force is being absorbed by the brain. That statement is correct, but brain damage is related to impulse (which depends on both force and duration). I believe that has been measurements made which shows that headgear reduces impulse. This theoretically would reduces the amount of brain damage sustained if headgear was not wore.

The reason why impulse determines brain damage is because a higher impulse would cause a higher angular acceleration of your brain. Most of the brain damage is due to angular acceleration, which causes shear force that rips the neuronal connections. (layers of brain slide across each other ripping off the neuronal connections that joins them) Now you are not going to cause any neuronal damage from pressure. There has been a case reported by a neurologist where a high school student ran head first to a brick wall after losing a football game. He sustained enough damage to paralyze his limbs but was still conscious. THe reason why he did not suffer any brain damage is because his head did not move during the collision, therefore, his head experienced no angular acceleration and thus did not obtain any brain damage.

By experiences, I think I would have been knocked down if i was to ever get hit by hard shots to my head without wearing my topten helmet. But I've never sparred without a helmet.

I want to hear other thoughts regarding this issue. Has anyone sparred both with and without helmets? Did you find that you can take harder shots without getting knocked down while wearing a helmet?

 

[SLanD3r]

People always talk about bigger thicker gloves for better protection in sparring. Presumably placing the padding on the head would also help, so I'm not sure why people say it doesn't help.

Padding always dissipates some energy. I'm positive it helps, the issue is to what extent.

Apparently, those who think headgear only prevents bruises/cuts think the extra protection is marginal.

I personally think it does much more. Hardly conclusive evidence, but my winning headgear makes the difference between headache and no headache after sparring. That's relative to other types of headgear.

Compared to no headgear, I've gotten minor concussions before (headache, inability to focus etc...). This is all from sparring with the same set of people at anywhere between 40-80% force depending on person. Of course I'm aware that a hard-hitter will give you a concussion even if you wear a motorcycle helmet, but all things being approximately equal (same sparring partners with fairly consistent force each round), no headache v. headache or concussion seems to be a pretty big difference to me.

Obviously experiences will vary, other thoughts/experiences?

 

[SLanD3r]

QUOTE FROM TS:

"However, I don't believe that this is the case. Some people argue based on the fact that same amount of total force is being absorbed by the brain. That statement is correct, but brain damage is related to impulse (which depends on both force and duration). "

RESPONSE:
That first argument is incorrect and is completely erroneous. You're statement regarding force and duration is on the right track.

Following the logic of the first statment would mean that getting thrown on a mattress would hurt as much as landing on concrete.

The damage stems from sudden changes in speed (or in your words force dissipated over a very short duration, the shorter the duration the more damage). The more time and distance you give the object to deaccelerate, the lesser the impact/damage.

Think about it this way, if a car runs into a solid wall at 40mph, that's enough to total the car right (40 to 0 in the blink of an eye)?

But if the car runs 40mph into a huge pillow thats 50ft thick, the car now gets to dissipate the energy generated from 40mph over 50ft of soft cushion instead of 0 ft (the solid wall).

In another words, the deceleration is now spread gradually over a longer distance (or if you prefer the temporal scale, more time to dissipate the energy; but technically acceleration/deceleration is defined by a change a velocity measured in distance over time) and the damage will be minimal because the force is being dissipated at a much slower rate instead of one huge and sudden violent impact (the wall).

For brain damage from punching, the same analogy applies, except its the wall we care about (analagous to the skull) instead of the car (analgous to the fist).

The additional difference is that we are more concerned about the secondary impact instead (the brain smacking against the skull) after the skull is impacted. Of course the secondary impact of the brain is a function of how hard (force) and sudden (duration) the skull gets hit.


Damaging Punches:
If you guys haven't caught the inference yet (the inverse of what we're talking about), this explanation also sheds light on how to do the most damage with punches.

The punches that hurt are the punches with snap aka force applied in a short time (we want that sudden violent impact when we're the ones dishing it).

And of course the punches that don't hurt as much are the pushing punches, force applied over a longer time.

Caveat: the last 2 sentences might be a bit confusing since force is a function of mass and the change of velocity measured in distance over time (or simply F=MA). It's a semantical issue because I'm kind of inconsistent in how I use the word force, Sorry!

 

[GFG]

man i'm having a hard time finding any good information on this subject. i have even contacted 2 brain injury associations one in Canada and one in Boston to help point me in the right direction for making better headgear but never got a response from any of them.

Mike @ Gorilla

 

[csrichie]

Hey SLanD3r,
first of all I would like to thank you for your reply. I understand what you are saying. Yes you would damage an object if you apply enough force to it, such as throwing it against a wall. And that is why the foot ball player i described had his limbs paralysis, but note that his brain was fine. Yes his skull will be cracked if he ran into the wall faster without a helmet and yes his neck is probably damaged. brain however will not be damaged by simply being "crushed"

The general misconception people have is that brain damage results from brain "bouncing against your skull". I was taught in my medical biophysics class that this is not true. A retired neurosurgeon prepared the course regarding concussion, and one of the take home message was that brain damage does not result from pressure. He used several examples in illustrating this.

1. A patient was found with his skull crushed under a car. At the time he could hear his skull crack when the car came down on his head but he was still conscious. No neuro damage was found afterward.

2. that football player i talked about previously

3. I believe there has been experiments were they took monkey and they fixed their head to a wall. They found that when the head is fixed, they could not induce concussion by slamming hammer against it's head. (where as if the head is free to move, then concussion would definitely occur)

4. He once came across a patient who had cerebral hemorrage, or bleeding in his brain. He drilled a hole inside the patients head in the ambulance in order to relieve the pressure. The patient's symptom improved (cognition restored) on his way to the surgery room and there was no neuro damage afterward. (if the symptoms were caused by damages to neurons, then the patient will suffer from irreversible symptom that would not be restored after the pressure is relieved)

Now all these examples is trying to convey the point that: brain does well with pressure (it can be compressed and bounce back to its original shape without suffering damage). But it can not withstand shear force (the force of two surfaces sliding pass each other).

Hope that made it more clear!

 

[SLanD3r]

@Mike:

There probably aren't many studies on headgear for boxing, however you might want to check out the studies on helmets for motorcyles and cars. I believe there is much more literature there.

ANSI, SNELL, ASTM are a couple organizations that set the standards there. ASTM sets the standards for other sports including equestrian and even downhill mountain biking.

Although the application is different for the fighting sports, there are some univeral principles of physics that apply to both.

Dunno if you read that sh*tstorm I posted above, but you can gather from that that the thicker the helmet the better (albeit the rate of compression of the padding plays a really important factor too).

The main thing is that the more gradual the deceleration the better, and that means the thicker the better (of course you can't forget the rate of compression as mentioned earlier, sort of akin to the compression portion of vehicle suspension tuning, obviously rebound doesn't apply here), problem is it can't be too thick or it gets in the way of the athlete.

Here's to get you started:

Helmet Performance: Blowing the Lid Off - Motorcyclist magazine

Snell's response to the above article:
http://www.smf.org/articles/pdf/btlo_tech_response_2.pdf

Motorcycle helmet standard comparison:
http://www.smf.org/articles/mcomp2.html


Observation on winning headgear:
One thing I noticed about my winning headgear is that the outer padding is a bit harder than the inside portion. I believe the reason is that a harder outside surface will help distribute the impact over a larger surface area, and the softer inside is to cause a more gradual compression (smooth out the deceleration process).

That's also how car/motorcylce helmets are too, hard outside, softer inside.

 

[SLanD3r]

@csrichie:

OK, I gotcha now. So brain damage results from more of a tearing force if you will, and not from perpendicular impacts.

Since the brain is kind of mushy the damage must result when a portion of the brain catches the side of a skull and the brain kinda bends around that point of contact? That's how I would imagine shearing forces would be created.

That would seem to explain why getting hit in the chin does so much damage. The chin is about as far from the brain as you can get on the skull where there is maximum leverage. Plus, since the chin is one of the "corners" (if you can call it that) of the head it would seem to cause the most angular acceleration when hit.

Regarding points #1 and #3: yea, the damage would seem to be isolated to just the skull, the whole head has to accelerate/decelerate before that brain gets tossed around.

Regarding #2: the trauma would seem isolated to the front and back of the brain, but unless he hit at an angle this would seem just to be a perpendicular impact for the brain and as you said this doesn't cause permanent brain damage.

Regarding #4: depending on how the liquid was applying pressure on the brain, it seems that if the pressure was great enough on a smaller portion of the brain that shearing forces could be generated around the circumference of the point of pressure.

But if the pressure was on a whole side of the brain then it would be more like #2.

 

[csrichie]

Hey SLanD3r,

Yes, you are correct. Brain is elastic, or in other words meshy. and yes, shear force is tearing, and it occurs when you slide the brain against something.

Now, this meshy brain is held up in the skull by it's brain stem i believe (It had been a year since i took the course). The rest of the brain is relatively free to move around. When your skull rotate, part of your brain that is anchored will slide while your brain stem is fixed. This then tears the wiring apart. This why you get knocked out when you get punched in the chin - the force will rotate your head at high angular acceleration following by a abrupt stop. This is also why people with strong neck can take harder shots. and why you should take shots with your forehead cause your brain won't move as much.

This is why I think impulse matters more than the amount of force. It's like being hit by a baseball bat and being slowly crushed. If the force is applied over a short period of time at the right spot, your brain's angular acceleration is going to be greater. You are correct that helmet does decreases the total amount of force. But I think the more important thing that helmet do is that it spreads out the force over a longer periods of time and slows down your angular acceleration.

Now there might be some sharp points along the skull that your brain can be compressed against, resulting in damage. However the inside of the top of your skull is pretty smooth. I think generally your brain wouldn't be pressed against those surfaces unless you have to crush your skull first. But I'm not sure about that... Generally as long as your head is fixed and there is no sliding of one surface over the other, you wouldn't get concussion is what i understood for my course.

 

[GFG]

the monkey pinned up on the wall scenario reminds me why i was taught to turtle up my neck when sparring, this way my head is more stable and less likely to get rocked from incoming strikes as my upper body is stabilizing it in place. As for the the shearing effect you guys are talking about reminds me of what may happen when getting clipped on the button (jawline) which slips your head around very quickly.

i'll take a peek at those articles and see if i can make sense of it to help build better headgear.

i remember reading articles on rugby headgear and they made it sound like rugby headgear was a waste of money, but then again those headgears have a honeycomb style of padding which may conform nicely with your head but i can't see this type of padding dispersing energy over a wider surface, also the headgear tends to be very dense and fairly thin i think it was 1.6cm (0.62inches) thick was the thickest headgear they tested. The thicker rudgy headgear did do better then the thinner headgear.

as for the winning headgear that i have recently ripped apart there was no harder layer it was fairly soft through out, before i ripped it open i assumed it was a injection mold it was so soft. however their is a harder layer of foam used in the forehead but that's not the outside layer. but i totally under stand what your are talking about from using a denser foam on the outside to disburse the energy then having a softer layer to absorb that energy that is now spread over a larger surface.

also i did find an article a while back where they did tests with boxing headgear but there were to many details missing from the article. So in the end all you got was having headgear is better then not having it.

In reality there is no subsitute for a proper posture with the chin tucked in and a neck that's turtled

mike @ gorilla fight gear

 

[csrichie]

Now in turns of helmet design. I think it's sport dependent. Motor cycle helmets are designed to protect your head from crashes at high speed where the kickboxing helmet are designed for taking punches. Therefore, I believe that helmets are designed to provide you the best protection at it's designed range.

I believe this is why motor cycle helmets are hard rather than made of foams. You wouldn't want to wear your winning headgear to ride a motor cycle because once winning gets past the range it's designed for it's going to lose it's protective effect. The foam may be so compressed that it can't take any more force.

So to design a helmet, you must know the range of force you are dealing with. Then select a material that will work best at that particular range. If you strap a pillow on your head, it will protect you from your sister's ground and pound but not going to do you much good from Carwin cause the foam will be so compressed it's not going to protect you at high range.

That's my best guess at it. Could the helmet provide enough protection is another question.

 

[GFG]

yeah then you have to take into effect what your are getting hit with a soft glove or and hard surface like a shin or knee. That is why boxing headgear like winning tends to be softer then muay thai headgear like twins or fairtex

 

[SLanD3r]

@csrichie

Regarding designed ranges. Unfortunately this is a rule that applies to just about everything. The better something is for one situation, generally the worse it is for something else =(

. . . or you could have a jack of all trades that is mediocre at everything.

It's a shame, because it usually puts a pretty hefty dent on my pocket book because for every hobby I have, I have a huge collection of equipment that caters to specific situations and when the situation changes, it's time to reconfigure my equipment. . .

If we were really hard up on safety I guess we would have different headgear designed for different weight classes, and/or maybe different headgear for different types of punchers.

@Mike

Ahhhh, I never thought about that but it makes perfect sense (the thing about thai equipment being harder than boxing equip).

I wonder if you can use that material that stiffens up proportionally to how hard the impact is to try to get the best of both worlds. Forgot what the material is called, d30 or something? It's really pricey though.

Updated: just looked it up its d3o, d3o Lab | the impact protection company

Since you're willing to rip up winning headgear I figure you might be willing to check the d3o stuff out haha.

Oh one more thing, when are you guys coming out with the sparring vests. I'm in the market for one.

 

[PeterPain]

Headgear protect from cut and bruises and mild brain trauma.
That said, someone punching at full force to your face could lead to serious injuries.

Ducking may be the better tool to have while sparring.

 

[Genki Pseudo]

i think your missing the point. headgear gives the impression you can punch the person much harder than normal, whilst giving disproportional resistance to damage.
in other words you get hit alot harder wearing it, but it only gives minor benefits

 

[GFG]

@csrichie

Oh one more thing, when are you guys coming out with the sparring vests. I'm in the market for one.

it will be alittle while i have no real date set to when they are going to be back in stock, i could rush it and just make a generic product but then i'll probably end up clearing it out as i wouldn't be able to meet my expectations

 

[melcron]

i think your missing the point. headgear gives the impression you can punch the person much harder than normal, whilst giving disproportional resistance to damage.
in other words you get hit alot harder wearing it, but it only gives minor benefits

How about wear headgear and don't be a moron? Why is this never an option with these arguments ? If you keep reality in mind and limit your striking force while wearing protective gear it will give more than minor benefits.

Just because some people are too ignorant/oblivious to use something properly doesn't mean everyone should stop using them.

Edit: I just realized this post was unintentionally harsh sounding. My intention wasn't to insult anyone, I just have unwise word selection at times.

 

[Tone C]

My head hurts after reading this thread.Should I wear headgear,will it help?:icon_conf

 

[GFG]

i think putting on some headgear is a good bet, but you still need to communicate with your sparring partners so they don't misunderstand that you putting on headgear doesn't mean you want them to take it up too 110% by trying to knock you out with every punch or kick.