admin edit

So, the facts I've found:
- in contact sport a layer is regularly exposed to strikes to the head/body. This increases chance of c/TBI.
-The articles in that search are more often than not, with players wearing helmets ect which would require a greater force to overcome such protection.
-There are cases of 120g with no concussion.
-There are cases with 20g resulting in concussion.
-Direct force to head is not always the case, rotational and lineal forces ect are very hard to measure and research is being done but results are not concluded.
-there are cases of regular 2g force, from spinning in skating, leading to persistent concussion symptoms
-Newton's 3rd law should always be considered, but is often hard to factor in injury incidences.
-it is possible a slap will cause 100's of g force, briefly to a local area, with no damage
-sustained low g force can cause much damage/death, specially if it is of the same frequency of an organ.
-underlying cardiovascular issues decrease g force tolerance
-g force tolerance can be increased by training or countering if blow is seen coming

In conclusion, it is incorrect to say that a 70-90 g force is required for concussion. At best this is a generalisation. There are simply too many variables. I spent 15 minutes researching.

*admin edit* I have already posted, before this comment, which i think should make clear why this question was asked.

Also, it must be noted that this is clearly a fad subect in the USA at recently. NFL ect is big money, the sport is dangerous and that comes with insurance issues. This will have an effect on the research conducted. In other parts of the world, who do not hae such financial investment, it somewhat a moot point. Folks getting attacked, or involved in car accidents (non sport) ect do not factor in this research.

Fro what I can see the research is also flawed in that it does not account for individualistic variables.

Yes it is important to regulate health concerns in sort, whether contact of racing ect, but this is a narrow view and one which is not entirely applicable to most posters here. Most people are not physics whizzis nor do they happen to have measuring devices at the time of accident. It is all very hypothetical, and can seem dismissive of those who are suffering.

Ash,

You are dead wrong about the US research. Most was done without any involvement of the NFL or NHL. They actually fought against the research. It is the injured community that pushed the research, against the insurance companies and other financial interests. Concussions are not a fad issue. The internet just made it so more people can access information without the financial interests getting in the way. A few researchers were able to get their research in front of enough people to achieve critical mass. Motor vehicle, falls, assaults and other causes have always been an issue here.

The increased popularity of soccer, your football, and Title 9 access to sport for women/girls has brought injured girls into the public sphere. Parents often take a greater interest in the health of their daughters than their sons. Mother's have driven much of the public interest.

The 20 G concussion and the 120 G non-concussion are debatable issues. There has been a world wide struggle to define a concussion and MTBI. The 20 G concussion likely happens to a subject with quite a history of concussions. The 120 G non-concussion is likely somebody who has never suffered a concussion. Some are more tolerant of impacts. But then, as has been stated here many times, If you have seen one brain injury, you have seen ONE brain injury. There are a myriad of mitigating factors and differences. Neck issues, etc. can make a big difference.

As you claimed, the research can be flawed. The 2 G concussion claim could be just as flawed. I'm not saying it was. I read research regularly that is not flawed but limited in what it can address. People take the research and make assumptions based on misunderstanding the limits of the research.

Just as you contest the research, you do not have all of the answers either. This forum is not about exacting concepts. They do not exist regarding these issues. Research is a system of compiling evidence with models that are intended to reduce the errors. Often, they only find errors as they do the data collection. As they eliminate these errors or abstracts, they can become more exacting. But, they can't do that with concussions. So, they use a broad cohort.

There is currently a controversy about how to properly collect the concussion data needed to fully understand concussions. The US Veterans' Administration has spent millions trying to identify concussions vs similar clusters of symptoms that may be due to other causes.

So, there is no perfect answer. All we have is the research being done. Most of life is based on similar concepts. If we live life based on the outlier ideas such as " a concussion from 2 G's" we will be paralyzed. If we use common sense and reasonably moderate our behavior based on what we observe personally, we can hopefully move forward. Fretting about involuntary head jerks in bed is problematic when one can currently not do anything to end those head jerks. Stopping compulsive head jerks or head banging to music is worth the effort.

If you will read my comments, I said, "They usually use 60 G's " and "20 to 40 G's." Somebody who can not tolerate 2 G's would need to stay in bed. Walking can impart 2 G's to the head. I know the physics and have run the numbers. G's relate to acceleration and deceleration. Both are changes in speed over time. A sudden stop against a fixed object can cause high G forces for very small time increments. A jerk of the head does not not have that sudden change. It would be near impossible to achieve 20 G's with a simple head jerk. The muscles are just not strong enough to start and stop in the time and distance needed to reach those levels. The repetitive effect of shaking can cause trauma at lower G forces.

The research says that the brain can often tolerate extremely high G forces for miniscule time periods. It is the G force sustained over time that is most problematic.

But, when a question is asked, the available answer is usually based on research or at least a large amount of anecdotal evidence.

btw, You said "-The articles in that search are more often than not, with players wearing helmets ect which would require a greater force to overcome such protection." You ignored the fact that the research is based on G forces at the surface of the skull, not at the exterior of the helmet. There are accelerometers that are less than 5 mm thick by 10 to 15 mm square that are fitted against the skull with the helmet and padding holding them tight against the skull. They are set to measure G forces in multiple axis. Some use piezoelectric effect to sense movement. These are accelerometers similar to those in an iPhone that sense position.

Happy Birthday for the other day Mark btw - seems like you switched from being 59 to 60 recently right?

*
You have also moved the goalposts, so to speak. From talking about force required to cause concussion, to that of specific contact sport incidences. *

*, ignoring sustained, rotational, cenrefugal forces ect). Even with those who are gifted in this area it would be a very impressive feat; not only to measure the variables but to calculate them. Perhaps as sensory tech advances and quantum computers crack prime numbers we will see an improvement here.

* HITs only measure above 15g and only for 48ms. This has been used to improve protective wear and provide predictive (not certain) values.

As I have said the fact remains that there are little facts. There are observations, trends in data ect but no true answer. It is misleading to claim there is*

This is an interesting link, and yes looking at american football. The whole thing is worth reading but I'll pull a few key lines from the conclusion.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2943536/

"Ultimately, the analysis fell short in identifying a single variable or set of variables that predicted concussion in high school football athletes on a level that can used for diagnostic purposes. The use, therefore, of the Head Impact Telemetry System as an acceptable diagnostic tool is not warranted at this time. The HITS can, and does, provide a clear indication of which individuals necessitate further evaluation following an impact."

Reference:-The Biomechanical Properties of Concussions in High School Football
Steven P. Broglio, PhD,1 Brock Schnebel, MD,2 Jacob J Sosnoff, PhD,3 Sunghoon Shin, MS,3 Xingdong Feng, PhD,4 Xuming He, PhD,5 and Jerrad Zimmerman, MD6

Yea, I hit the big six-o early in January. Boy, I feel old.

We are re opening this thread at this time..please stay on topic with replies to OP..
Thank you

I researched as well, and found the following informations:

A fall into a chair creates about 10 g and is sufficient to cause a concussion.

Sneezing and coughing, like we all do everyday, creates about 3 g.

I also saw the research results about nfl players. They said that helmet collissions, which create about 50-60g can cause concussions. But the helmet acts like a second skull, providing additional protection to the head. So this number can probably not be taken for impacts whithout helmets.

(I cannot add links as my number of posts is less than 10)

My second concussion was caused by a fast tennis ball that hit me straight on the head.
According to calculation in a physics forum, a tennisball served at 200km/h creates a force of 3g(the same as sneezing). I don't understand it. How can this tennis ball cause a concussion, when it has the same force on the body as a simple sneeze?

Any idea what the g force might be in a head on collision? Say, at about 50 miles/hr.

Just my humble opinion here, but there are far too many variables to be answering these types of questions.

i.e. were you wearing a seatbelt.
Was there an airbag deployed.
What side of the vehicle was hit.
How heavy was the other vehicle.

etc.

Tennis ball. I know a sneeze can be powerful and I know that sneezing can cause people to herniate discs, but again the problem with asking those types of questions is that there is no simple answer.

There are too many variables.

How thick is your skull?
How inflated was the ball?
What side of the head or face or forehead or neck did it hit?
Did you jerk your neck back really fast?
etc.

There is a book called
Concussive Brain Trauma -
Neurobehavioral Impairment & Maladaptation
By: Rolland S. Parker

it might explain some of the more technical and highly variable physics relating to impact.

You can often use specific keywords and search some advertised books online.