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Re: Hockey Helmet Safety Rankings

anon
Anon
Methodology was off, it was a flawed study from the start, they recorded only one type of impact. It is far from the bible on helmet safety, and it\'s already outdated.
https://kstp.com/kstpImages/repository/cs/files/ABME%202015%20Hocky%20STAR%20Rowson%20Rowson%20Duma.pdf

If you want to understand how they are testing the helmets, above is the published abstract.

"The laboratory testing matrix includes 3 impact energy levels and 4 impact locations, for a total of 12 testing conditions per helmet. In practice, two helmets of every model will be purchased. Each of these helmets will be tested in the 12 conditions twice for a total of 48 tests per helmet model. The two acceleration values for each helmet’s test conditions will then be averaged for each impact condition prior to using the risk function to determine probability of concussion.

Concussion risks will then be multiplied by the exposure values for each impact condition to determine incidence values. All incidence values are then aggregated to calculate a Hockey STAR value for each helmet. The Hockey STAR values for each helmet will then be averaged to determine a helmet model’s overall Hockey STAR value."

It doesn't, in my mind, explain the wild differentiation in testing scores in similar model helmets. Besides statistical error, my only other thought is in difference of internal materials or location of the materials. If the point of impact is not where a dispersion material is, i.e. foam, are the sensors recording significantly higher forces and is that point of impact realistic during game situations? I have no idea how accurate their testing methodology is in real world situations but I do like the fact the VT study is making an impact in design and construction of our kids safety equipment.
Thanks. I agree with you, it's nice that they did it. But, the failure to use statistically valid methods cripples the study.

They tested only two samples of each model. Then they averaged the results. Suppose the results were anomalous, with one helmet getting an 8 and the other a 1. The published result is a 4.5, which is not at all indicative of EITHER test.

I'm no statistician, but I do remember that mean is the most likely point of central tendency to be influenced by outliers or extremes. Especially when the N is 2.

Re: Hockey Helmet Safety Rankings

anon
Anon
Methodology was off, it was a flawed study from the start, they recorded only one type of impact. It is far from the bible on helmet safety, and it\'s already outdated.
https://kstp.com/kstpImages/repository/cs/files/ABME%202015%20Hocky%20STAR%20Rowson%20Rowson%20Duma.pdf

If you want to understand how they are testing the helmets, above is the published abstract.

"The laboratory testing matrix includes 3 impact energy levels and 4 impact locations, for a total of 12 testing conditions per helmet. In practice, two helmets of every model will be purchased. Each of these helmets will be tested in the 12 conditions twice for a total of 48 tests per helmet model. The two acceleration values for each helmet’s test conditions will then be averaged for each impact condition prior to using the risk function to determine probability of concussion.

Concussion risks will then be multiplied by the exposure values for each impact condition to determine incidence values. All incidence values are then aggregated to calculate a Hockey STAR value for each helmet. The Hockey STAR values for each helmet will then be averaged to determine a helmet model’s overall Hockey STAR value."

It doesn't, in my mind, explain the wild differentiation in testing scores in similar model helmets. Besides statistical error, my only other thought is in difference of internal materials or location of the materials. If the point of impact is not where a dispersion material is, i.e. foam, are the sensors recording significantly higher forces and is that point of impact realistic during game situations? I have no idea how accurate their testing methodology is in real world situations but I do like the fact the VT study is making an impact in design and construction of our kids safety equipment.
It's because they didn't perform an gage R&R to determine the variation from the testing method.
Engineering 102.

Re: Hockey Helmet Safety Rankings

This may be the winner for the most intelligent dboard discussion ever.

Re: Hockey Helmet Safety Rankings

A helmet will never prevent a concussion. Concussions are a physiological response to trauma when the brain impacts the skull due to impact or rapid deceleration of the head. Helmets are better suited for protecting the skull from fracture due to direct trauma. A manufacturer's claim is more a marketing bullet point than science

Re: Hockey Helmet Safety Rankings

Anon
A helmet will never prevent a concussion. Concussions are a physiological response to trauma when the brain impacts the skull due to impact or rapid deceleration of the head. Helmets are better suited for protecting the skull from fracture due to direct trauma. A manufacturer's claim is more a marketing bullet point than science
That is 100% false. A helmet can't prevent all concussions, particularly rotational movement. But, it can prevent some, especially translational (back/front) movement.

Helmets also dissipate the force created by impact over a larger area and provide for deceleration, meaning the head takes longer to slow down following impact, so the movement is less abrupt and the brian moves less.

And, the foam absorbs energy created by the hit, which is why you should replace a helmet after a significant impact, and never buy a used helmet since you don't know its history.

Now, go give Kyrie a call and chat about how the earth is flat.

Re: Hockey Helmet Safety Rankings

The "A helmet will never prevent a concussion" guy always posts on this topic and there is substantial evidence this guy has been wrong forever. Maybe he is a Bauer 4500 'concussion bucket' wearer for years.