[GlassHead]

I would like to hear others opinion on this.

I read this article:

http://www.sciencedaily.com/releases...0720210700.htm

It claims that: A concussion occurs at roughly 90 to 100 g-force, "which is like smashing your head against a wall at 20 mph," Broglio said...

Well i got my concussion by standing up in a cabinet a lot slower than 20 mph. Am i extremely fragile or is the article wrong?

Sounds to me like 20 mph into a wall head first would be fatal or close to it.

[Mark in Idaho]

This article is relating to a football player who broke his neck with a head down block. The G forces relate more to the force required to break a neck.

The statement "A concussion occurs at roughly 90 to 100 g-force, "which is like smashing your head against a wall at 20 mph," Broglio said... may be a result of research that shows a immediate manifestation of symptoms.

Broglio mentions the sub-concussive impacts sustained during a football season. Nor does he mention the cumulative damage caused by those subconcussive impacts.

Glasshead, you likely have suffered many impacts prior to your concussion. Plus, there are many factors besides G force that cause a concussion.

What they do not mention is whether the 90 to 100 G's force is measured at the helmet or the skull. There can be quite a difference between the two, easily a factor or 2 meaning 100 G's at the helmet surface can be 50 G's at the skull with just 1/8th inch of deflection.

You also should not discount the speed of your head movement. 20 mph is 29 feet per second. Between the speed of the body movement and the whipping action of the head and neck, the speed at impact can be much higher than one would suspect.

But, I think the primary issue is your brain has developed a sensitivity from sub-concussive impacts that makes minor impacts enough to cause a concussion.

[Scott in Fenton]

I'm starting to think people have undiagnosed concussions more than they think they do/did, or at least I have. I was asked if I have had a concussion before, and I said no because I've never been diagnosed with one, but I know I've hit my head a number of times in the past, just never sought treatment. I can think of 4 good possibilities in the past 10 years or so when I hit my head pretty good, enough to leave a sore spot and either a bad headache or a stiff/sore neck for a day or two, but did not go to the ER or anything else. So, this current concussion could be my 5th, but only my 1st diagnosed, and therefore the PCS makes more sense.

I think a lot depends on where you hit and the angle of the hit. In my case the unmoveable object was above me in the ceiling, and I was the one moving backwards towards it about as quickly as a guy can backstep. How fast is that? I dont' know, but I know I was also turning my head at the same time, possibly adding some speed/centrifugal force or whatever, my head was forced downwards and away from my body at the same time. No contusions or bleeds, but a lot of force that whipped my brain around. Plus I hit myself right behind one of my ears, just at or below the edge of my skull, where two major nerves enter the head. Same place where kids playing the "knock out game" hit you. Again, I was not going 20 mph, probably, although my head might have been for just a second or so, but still the results are the same; 4 months later and still suffering most of the same symptoms.

[GlassHead]

Originally Posted by Mark in Idaho

This article is relating to a football player who broke his neck with a head down block. The G forces relate more to the force required to break a neck.

The statement "A concussion occurs at roughly 90 to 100 g-force, "which is like smashing your head against a wall at 20 mph," Broglio said... may be a result of research that shows a immediate manifestation of symptoms.

Broglio mentions the sub-concussive impacts sustained during a football season. Nor does he mention the cumulative damage caused by those subconcussive impacts.

Glasshead, you likely have suffered many impacts prior to your concussion. Plus, there are many factors besides G force that cause a concussion.

What they do not mention is whether the 90 to 100 G's force is measured at the helmet or the skull. There can be quite a difference between the two, easily a factor or 2 meaning 100 G's at the helmet surface can be 50 G's at the skull with just 1/8th inch of deflection.

You also should not discount the speed of your head movement. 20 mph is 29 feet per second. Between the speed of the body movement and the whipping action of the head and neck, the speed at impact can be much higher than one would suspect.

But, I think the primary issue is your brain has developed a sensitivity from sub-concussive impacts that makes minor impacts enough to cause a concussion.

Itīs probably true that the measured G-forces are on the outside of the helmets and not on the inside. This could make a huge difference on the actual G-force effect on the head.

But the claim seems to be backed up by other articles like this one:

http://www.sciencedaily.com/releases...0624092526.htm

Guess I have to search deeper in the literature if i want a better number. Models of induced concussion in rats are about 20 G but I am not sure it can be directly transferred to humans.

[Mark in Idaho]

GlassHead,

Why do you need to know this information?

[GlassHead]

Originally Posted by Mark in Idaho

GlassHead,

Why do you need to know this information?

I am toying with the idea of making shock absorbing car seats and I need to know the limits of when a person sustains a concussion. The theoretical framework needs to be in order before the actual design phase. I am not sure how far the idea will progress though but I like to keep myself busy

[Mark in Idaho]

I don't see how one could make a car seat that will absorb the energy that is transmitted to the head. The whipping action of vehicle movement will still impact the brain.

There are already air-ride seats and other suspended seats used in big rigs. They reduce the vertical component. Kenworth uses both seat suspension and cab suspension to reduce the impacts to the driver.

Cars are designed with crumple zones to absorb longitudinal energy transferred to the cabin. Airbags are designed to handle much of the rest. Side curtain airbags help with side forces.

[EsthersDoll]

There are already seats designed to take impacts to help protect the driver and passengers.

Start reading about "active head restraints" and that should lead you to a bunch of additional great auto safety technology.

Lexus: http://www.lexus.com/models/GS/safety/

Saab: http://www.driveandstayalive.com/art...-restraint.htm

Volvo: http://www.volvocars.com/us/top/abou...es/safety.aspx

There is a lot more to a car's safety than just the seat you are sitting in. You must also consider design and handling.

I did a lot of research in auto safety since the last car accident I was in because that accident gave me this head injury and the whiplash that caused bulging disks that I am still recovering from.

Curb weight also has a great deal to do with car safety.

(My last car was a compact car that weighed about 2200 lbs. which got great gas mileage! But it was totaled between two large SUV's while we were all at a dead stop when a fourth vehicle didn't stop. It had received the highest ratings available in its class for safety by the IIHS and the NHTSA. My new car is a midsize crossover SUV and weighs 4500 lbs., has active head restraints and 8 airbags and has also received the highest ratings in its class for safety from the IIHS and the NHTSA, but it had awful gas mileage.)

http://eetd.lbl.gov/ea/teepa/pdf/aps-ppt-wenzel.pdf

http://eetd.lbl.gov/ea/teepa/pdf/lbnl-3143e.pdf

[Mark in Idaho]

In 2002, when we had decided I needed to limit my driving, we were replacing a 1984 BMW 5 series, a car that ranked at the top of occupant safety until well into the 90's. We purchased a GMC Yukon. It had a very low injury rate and offered side impact air bags. Too bad GM was not putting the SAAB/GM active head restraints in it. They are only a $50 feature from what I can find.

Our previous full size GM vehicles had totaled three other cars with only minor fender and bumper damage to our vehicle. Today's models have more ability to absorb energy in the frame thus transmitting less energy to the passenger cabin.

The active head restraint systems are worth looking for when buying a car. The IIHS and NTSB have lists of the injury and fatality rates for different vehicles, usually expressed in a number of injuries per 100,000 miles or something like that. If I can find the link, I will post it.

[EsthersDoll]

I found this database helpful too:

http://www.iihs.org/research/hldi/co...px?y=2007-2009