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Discussion Starter #1 (Edited)
A few years ago, there were zero options for someone looking for a mountain bike helmet to reduce the risk of getting a concussion.

Today there's a gazillion different options, but figuring out how to choose among them is far from easy (mainly because the industry still has failed to come up with updated safety certification standards, indefensibly). This thread is my crack at a clear explanation and advice as of the start of 2020.

Short version: my guess is that 6D's ATB-1T Evo helmet [EDIT: or Bell's Super Air, or Bontrager's $300 Blaze Wavecel] is the best available helmet for reducing concussion risk. And my guess is that regular MIPS does not substantially reduce concussion risk.

[Me: just a mountain biker who's tried to follow all this since my own concussion in 2013. No industry affiliations of any sort, but also no engineering or medical training. A nerdy guy who's put some time into this, nothing more. I've owned a TLD A1, Kali Maya v1, Kali Interceptor, and Bell Super DH.]

MIPS


If you're considering a helmet to reduce concussion risk, the first thing to decide is whether you believe in MIPS or not. This much is now clear: if you take a grippy, rubber dummy head with no neck/body, and you strap a helmet firmly to it and then drop it onto a slanted surface and measure the rotational forces on the head, then a helmet with MIPS will score better. So if you believe that test measures real-world safety benefit, then you should buy a MIPS helmet.

We finally have independent testing confirming this by a trustworthy tester (a Virginia Tech lab with an insurance industry group). Their test results are here. (Their methodology detailed here and shown here.) Right now the two top-scoring helmets are the Bontrager Rally MIPS and the TLD A2 MIPS (and 8 of the top 9 are MIPS). So one reasonable option is to just buy one of them.

But not so fast. While VT's testing says that MIPS is the bomb, another body of independent testing says it ain't. Snell did testing in 2018 using a different procedure, using a headform--still bald and grippy, and still with the helmet strapped on tight, but with a neck and a body, instead of just a head bouncing free, like VT and MIPS iteslf use. Snell's testing showed no meaningful benefit from MIPS. More info here.

Assessing this conflict between VT's conclusions and Snell's, the independent Bicycle Helmet Safety Institute concluded:


Our conclusion is that this testing by a respected lab, reported by an organization with a distinguished history of consumer-oriented helmet activism, shows that MIPS is not likely to help you in a crash configuration similar to the one tested by Snell. Other lab testing using an unrestrained moving headform with a sticky rubber covering and no neck attached impacting a very rough 45 degree slanted anvil with the straps tight over an inflexible jaw (the configuration MIPS uses) has shown that MIPS does reduce rotational acceleration. But when the head is constrained--as by a neck--MIPS does not perform well. That does not happen in the field, where heads are attached to the body. We still think your helmet, with a normal scalp under it, will move anyway.

That sounds right to me. While trusting VT's data is appealing to me, and a week ago I was this close to buying a Rally MIPS for my next helmet based on their testing, but when it comes down to it I have more faith in Snell's test method than I have in VT's. If MIPS can't show a benefit without a free-bouncing head unconnected to a body, then I have no confidence that MIPS is doing anything.

[To be continued, I hope.]
 

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"doesn't help" and "makes worse" are completely different things. Nobody is saying that MIPS makes anything worse. Now, if two different testing methodologies are reporting conflicting results (doesn't help, and does help), my conclusion becomes more or less an average of the two - "might help". I'm going to buy something based on "might help" every single time.

But with that said, my primary consideration for a helmet is the FIT of that helmet on my head. MIPS or not, the helmet is going to work better if it fits.

Now, I know you have a historical agenda on this website against MIPS. While I don't exactly like the way helmets.org presents information, EVEN THEY more or less agree with me

Despite Snell's research we think the jury is still out on MIPS.
The fact of the matter is that we don't have conclusive information telling us that any of these tests are less informative than the others. They're all telling us something. The simpler your test, the more you're able to isolate factors. Make your test more complicated and the greater the risk that your results are confounded by the extra variables you've added. There's value to doing that sometimes, but it doesn't necessarily invalidate the simpler tests with simpler models. Discrepancies between the results simply mean that more testing is needed to figure out why those discrepancies exist.
 

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Discussion Starter #3
I agree with you that MIPS might help. If I were choosing between MIPS and non-MIPS versions of the same helmet I'd pick the MIPS. And to me the fact that VT chose the methodology they did counts for something. My views have shifted somewhat on all this, and may continue to shift as more info comes out.
 

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Discussion Starter #4 (Edited)
WaveCel

Bontrager (ie Trek) released helmets with a new concussion-reduction technology last year, which they call WaveCel. Their promo page is here, their WaveCel helmets, including the $300 mtb Blaze are here. They describe it thus: "WaveCel is a collapsible cellular material that’s incredibly effective at preventing head injuries caused by certain cycling accidents. It works by going through a three-step change in material structure on impact to absorb energy before it reaches your head." In photos it looks like it could be squishy, but actually its surprisingly rigid.

Bontrager claims that WaveCel helmets are "up to 48x more effective than traditional foam helmets in protecting your head from injuries caused by certain cycling accidents*." Their study shows an concussion risk of 59% for EPS helmets, 34% for MIPS, and 1.2% for Wavecel. And they claim all this is based on tests using a head + neck model, which is encouraging. The concept is reminiscent of Smith's Koroyd straws. The mesh covers front and back (unlike many MIPS helmets that have nothing but foam in back) plus a breakway accessory mount.

Does it work? Impossible to know yet. The 48x claim is from a study done by its inventors. It scores quite well (but below a handful of plain-vanilla MIPS helmets) in the VT tests. MIPS and Smith both fired back against Trek's performance claims. BHSI says they sent a WaveCel helmet to a lab for testing and it did "very good but not amazing," not quite as good as a Leatt DBX 2.0.

Is it expensive? Oh yes. MSRP for the Blaze is $300, the most expensive halfshell mtb helmet I'm aware of. That's absurd. But at least comes with 30-day unconditional returns and one-year free crash replacement.

It's entirely possible that WaveCel helmets are the best concussion-reducing helmets available today. It looks promising, and it's encouraging to see a big player like Trek finally trying to set the pace. If $300 for a trail helmet isn't a dealbreaker-- almost double the price of most of its competitors--then give it a look.
 

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I've been happy with the Bell Super DH protection.

Ive also been happy with the TLD Stage, but havent crashed it yet.

Sent from my LG-H932 using Tapatalk
 

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Discussion Starter #6 (Edited)
Single-shell designs

One of the main strategies for reducing concussion risk is to make helmets "softer." EPS foam is relatively rigid, which is good for reducing skull-fracture risk from big impacts but not good for reducing concussion risk from smaller ones. Traditional MIPS is a slip plane that's designed to reduce rotational forces, but it doesn't try to do anything to make the helmet softer to reduce concussion-level direct-impact force. So, many helmet makers have worked to find technologies that do both.

(Aside: my guess is that softness is at least as important as angular-force control. I suspect that our natural scalp slip + hair + sweat + imperfect helmet fit + helmet pads + normal strap looseness means that, in the real world, any helmet reduces angular impact forces and thus that regular MIPS provides little additional benefit. You may disagree with my guess; public data to answer it either way is sparse-to-nonexistent.)

Makers have taken two basic approaches to adding softness to bike helmets. (I'm ignoring dual-density foam for now.) One is to start with a traditional helmet--a single foam shell--and put something squishy on the inside where the helmet contacts the rider's head. Those are single-shell designs. The other is to design a helmet with two nested foam shells, an outer one and an inner one, and then sandwich something squishy between the shells. Those are dual-shell designs.

In both designs, the "something squishy" aims to do two things: deflecting under rotational forces and squishing under direct force. Picture a marshmallow, smushed from directly above or smushed from a 45 degree angle.

Here I'm focusing on single-shell approaches, where the squishy element is on the inside of the helmet right against your head. There have been a number of different approaches, including:

- Kali LDL (green lego-looking squishies)
- Leatt Turbines (blue disc-shaped squishies)
- POC Spin (the helmet pads themselves have squishy gel inside, notably in their Race Tectal Spin)
- Fluid Inside (the helmet pads themselves have fluid inside, notably in Fox Rampage fullfaces)*

Compared to dual-shell designs, single-shell designs have 2 big advantages: helmet size and weight. Dual-shell helmets are bigger and heavier, which makes them dorkier looking, less comfortable, and may offset their concussion-reducing benefit (weight increases force, diameter increases leverage). Single-shell designs are basically the same size/weight as conventional helmets.

But single-shell designs have disadvantages, too, although they may be less obvious. The biggest is coverage. If when you crash your helmet slams into your head where there's only EPS, not a squishy, then the fancy tech did you zero good. None of the existing single-shell designs cover the entire inside surface. For example, on the Tectal, the pads don't cover the back or much of the sides, as you can see clearly in these photos. In Kali helmets, the squishy strips are spread around the inside with many gaps. (Photo here.) I own the Kali Interceptor, and, when it comes down to it, I don't have a ton of faith that the LDL will be in the right spot in a crash, and that's why I'm replacing it now.

The other disadvantage I see with single-shell designs is that the safety tech is directly against your bony skull and your nasty headsweat, every ride. All helmet pads wear out from use, but in single-shell designs that same wear could degrade concussion protection. I recently discovered in my Kali that several of the LDL pads had deteriorated into a gross sticky mess without my noticing, and then it took me a while to hunt down replacement pads.

I discussed Trek's $300 WaveCel above. They're single-shell designs too, with the same size/weight benefits. Coverage looks like far less of an issue although I'm unsure about the rim, and I'd guess wear & sweat is less of an issue too. Hence my view that the $300 WaveCel might be the safest option available.

So if you're focused on reducing concussion risk, then choosing between a single-shell or double-shell design means guessing at how to balance risks. Which matters more, weight & diameter or squishy-tech coverage?

*EDIT: possibly MIPS SL belongs in this list too. It's another pad solution like Spin and Fluid Inside, made by MIPS and originally exclusive to Specialized, such as the well-regarded Ambush MIPS with ANGi. I say "possibly" because, while it seems similar to the Spin pads, they don't claim that makes the helmet softer, only that it reduces rotational forces like original MIPS only lighter. So hard to say whether it functions like the other pad techs.
 

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"doesn't help" and "makes worse" are completely different things. Nobody is saying that MIPS makes anything worse. Now, if two different testing methodologies are reporting conflicting results (doesn't help, and does help), my conclusion becomes more or less an average of the two - "might help". I'm going to buy something based on "might help" every single time.
This is where I'm at. I recently slammed my head and body into a ditch hard enough for the impact to break 6 bones. My helmet was dented in a couple of spots where I'm guessing it contacted rocks, with the impact telescoping through the foam and splitting my scalp, requiring a few stitches but no concussion. It was a MIPs helmet. Whether the MIPs made any difference, I don't know, possibly not due to the more direct impact rather than glancing. But I don't believe it made it worse and I'll take the "might help".
 

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Discussion Starter #8
This is where I'm at. I recently slammed my head and body into a ditch hard enough for the impact to break 6 bones. My helmet was dented in a couple of spots where I'm guessing it contacted rocks, with the impact telescoping through the foam and splitting my scalp, requiring a few stitches but no concussion. It was a MIPs helmet. Whether the MIPs made any difference, I don't know, possibly not due to the more direct impact rather than glancing. But I don't believe it made it worse and I'll take the "might help".
You're both stuck in the past.

Four or five years ago, "is MIPS better than nothing?" was the relevant question, because MIPS was the only concussion-safety game in town. But now the relevant question is "is MIPS better than the other technologies trying to reduce concussion risk?"

The answer to that, admittedly, isn't clear. If you believe in the VT testing (and reasonable people do) then the answer is basically yes. If you believe Snell instead (as reasonable people also do), then the answer is probably no.

But, in 2020, the argument that MIPS doesn't hurt and might help is beside the point.
 

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If you're considering a helmet to reduce concussion risk, the first thing to decide is whether you believe in MIPS or not.

It's like 30 extra dollars and they tend to fit me better. I don't need to "believe in MIPS" to think that the research behind it has some validity, they've done a heck of a lot testing & research than I have. I figure it can't hurt so I'll take my chances.
 

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But, in 2020, the argument that MIPS doesn't hurt and might help is beside the point.

I don't think so. Most of the helmets that are available and fit my criteria happen to have mips technology so that's what I'm likely to choose. Trek Wavecell may or may not be superior but for now I don't like the fit and they're a bit heavy. Don't know about Kali because I haven't really checked them out and there's none for sale around here. Anyway, I think the best helmet is the best one you can find that you always wear.
 

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The answer to that, admittedly, isn't clear. If you believe in the VT testing (and reasonable people do) then the answer is basically yes. If you believe Snell instead (as reasonable people also do), then the answer is probably no.
I don't believe for a second that my only choice is a false dichotomy of choosing one test over the other. As I said before, they're both informative. Whether you draw reasonable conclusions is up to you, and I tend to feel like you're leaping to conclusions that aren't supported, and you ask the wrong questions.

I also don't believe that the true question is "is MIPS better than other technologies trying to reduce concussion risk" either.

Right now, there is no evidence to suggest that one concussion reduction technology is any better than another. In looking at the VT tests (the more controlled between the two you have brought up), not all MIPS or Wavecel helmets consistently ranked better than the others. One Wavecel helmet was #1, and a MIPS helmet was #2. That there were more MIPS helmets on the list overall means that more MIPS helmets were tested. There are other factors not described in the results that play roles in whether an individual helmet scored better than others. Some of them are very onerous to even attempt to test. Also, not all helmets with every possible option were included in the test for various reasons (most of which are more practical ones than any sort of bias).

Most importantly, not every competing technology is available to me to try on for fit at my local stores. I'm just not going to buy a helmet I can't try on for fit first. I'm going to buy what fits me well and what I can try on for fit before I buy. Protective gear like a helmet is not the kind of thing I'm going to buy sight-unseen and then attempt to return if it doesn't fit.

I recently bought a TLD A2 MIPS helmet to replace my Bell Super 2 MIPS. The Bell was okay, but it didn't fit as well as it could have and it was a stuffy helmet. I never tested its concussion risk reduction, but I simply got tired of its less than ideal fit and stuffiness. I had the TLD A2 MIPS on my radar for years because it fit so well and was so much more breathable. That's why I bought it. The VT ratings for the helmet are icing on the cake. Do I think I'll be able to avoid a concussion by wearing the helmet? God no. I'm not a moron. I do think it's better than my previous helmet, and it actually incorporates multiple protective methods that my previous helmet lacked to address different types of impacts.

That, right there, is I think where value lies. Incorporating multiple protective methods/technologies/materials that each has its own strengths to create a complete package that maximizes potential protection.
 

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Discussion Starter #12
That, right there, is I think where value lies. Incorporating multiple protective methods/technologies/materials that each has its own strengths to create a complete package that maximizes potential protection.
I agree 1000%. Getting to that in chapter 93.

Broadly agree with rest of your post too, although my take on fit may differ somewhat (and the current VT rankings are a little different than you describe, but whatever).
 

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My understanding is that the main issue with concussions is that to withstand the higher speed impact specified in typical crash standards, helmets need firmer foam to absorb those higher impact forces, but that same foam does not do well with slowing head movement at a more gradual rate. Using only one density of firmer foam helps reduce the severity of brain injury but is less good at reducing impact velocity at a more gradual rate. It seems to me that MIPS does not resolve that issue.
 

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Discussion Starter #14
My understanding is that the main issue with concussions is that to withstand the higher speed impact specified in typical crash standards, helmets need firmer foam to absorb those higher impact forces, but that same foam does not do well with slowing head movement at a more gradual rate. Using only one density of firmer foam helps reduce the severity of brain injury but is less good at reducing impact velocity at a more gradual rate. It seems to me that MIPS does not resolve that issue.
My (again, non-expert) understanding is similar but a little different.

My understanding is that there's universal consensus that reducing rotational forces is essential. Whether the different existing designs actually achieve that is hotly debated, but everyone agrees that reducing rotational forces on the brain would reduce the number of concussions.

Many (but not everyone) believe it also is important to reduce lower-force direct impacts, what I refer to above as making helmets softer. That's the hard-foam problem you refer to.

No one believes a softer helmet that does nothing to reduce rotational forces is the best solution. MIPS advocates say that a helmet that reduces rotational forces that does nothing to be softer is the right solution. I believe the best solution must address both, and several existing designs seek to do so--the single-shell designs above, and dual-shell designs I'll get to below.
 

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Discussion Starter #15 (Edited)
Dual-shell designs

This thread is too long already so I'll try to be more concise.

Dual-shell designs (see #6) offer the flip side of the coin from single-shell designs: bigger and heavier, but better coverage. Dual-shell designs eliminate the question about whether, in a crash, the squishy whatzits are going to be in the right spot, because the entire inner helmet surface is suspended by the sandwiched squishies.

Two dual-shell designs:
- 6D ODS, in ATB-1T Evo
- MIPS Spherical, in Bell Air DH, Bell Super DH, Giro Tyrant, etc

I currently own both the dual-shell Super DH and single-shell Kali Interceptor, and, contrary to my own biases, I have much more faith that MIPS Spherical will function as designed in a crash than that Kali's LDL will.

Comparing the two current dual-shell designs, 6D's ODS is a little different from Bell/Giro's MIPS Spherical in a few ways:
1. With ODS, the inner shell is the only thing that touches your head--in MIPS Spherical, the inner shell doesn't cover the lower back of the helmet, from your ears back.
2. The linear-force squish is much clearer with ODS. With the 6D, when you pinch the inner and outer shells you can feel them move. With Spherical, while the rotational-force slip is obvious, the linear-force squish isn't.
3. On the 6D, the inner shell is EPS, which is relatively rigid. So all of the softness in the 6D design appears to be in the bumpers. On the Spherical, the inner shell seems to be EPP, which likely is softer than EPS.
4. The 6D is 501g, the Super Air is 421g (both medium per Pinkbike) and the Super Air isn't as big.

I see potential advantages for either design, and I don't have even a guess about which is overall more effective at reducing concussion risk.
 

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--holy crap you will solve nothing here

--a helmet that fits, and that you want to wear, and fits with cycling, it the one to use

---and -maybe- picking ones from the top of the list of the technical testing reviewers is a better choice than the lowest ones on the list


statements like this:
I have much more faith that MIPS Spherical will function as designed in a crash than that Kali's LDL will.

well, that works for YOU. have you thought of each and every of the 21 trillion ways your head might receive physics education and punishment from the combined variable forces of speed, gravity, inertia, kinetics and the ground or tree or bike or body you slam into ?

but you really don't know

and will never know, until you conk your head while wearing one.

and guaranteed, someone somewhere will conk their head in the most advanced helmet in the world and they'll still get a concussion.

so, these type of internet forum arguments are much ho-hum....just don't conk your friggin head in the first place, and if you do, all bets are off despite all your armchair research.


for a helmet to work it has to be: yours, and worn correctly

and also that means affordable

that means it fits your crazy skull shape

that means it is light enough to not make you want to stop riding
because the helmet is too heavy

so many variables here....you want real answers get a supply of helmets and a supply of virtual monkeys and start tossing them off cliffs, and then do cat scans of the damage...otherwise all these top helmet manufactures actually are trying pretty hard to solve the unsolvable and you can only guess and hope you don't conk your skull in the first place, no matter what you use on the noggin


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so, you say you want no concussions ? don't leave your bed, ever, and make sure that bed is at the bottom of the deepest salt mine in the most geologically inactive location on the planet...

sorry but I got a big beef with picking apart the tests and studies apples/apples/apples/oranges arguments....
 

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Discussion Starter #19
Old tech

Up until now, I've focused on the various new, high-tech approaches to reducing rotational forces and/or making helmets softer, but there are lots of non-high-tech approaches, too. The designs I trust the most don't just rely on one fancy gizmo: they combine a number of different strategies for reducing concussion risk. Without reliable independent data, for all we know the low-tech stuff is more effective than the gee-whiz stuff.

Softer foam
Rigid EPS foam is how helmets meet existing certifications and protect your skull from big impacts. But Kali figured out a clever hybrid solution, dual-density foam (which they market as conehead / Composite Fusion Plus), so that the shell has enough rigid EPS to protect against big hits but also has softer foam to cushion softer, concussion-level hits. (Nerd out here.) The benefit seems obvious, with no apparent downside but cost and even that's modest since they've got several sub-$100 helmets with it. The newer Troy Lee A2 MIPS and some Fox helmets have dual-density foam too. I wish every MTB helmet had it.

Breakaway attachments
Almost all MTB helmets have visors. And many of us ride with lights or cameras. In a crash, those do-dads can snag and jerk your head, increasing rotational forces on your brain. So, safer helmets have breakaway attachments for visors and accessories, strong enough to keep them on when you ride but weak enough to separate without snagging when you eat it. Breakaway visor bolts and go-pro mounts aren't as sexy as MIPS or Wavecel, but I wouldn't be surprised if in reality they matter just as much.

Helmet shape

Another factor that can determine whether your helmet slides or snags is the shape of the shell itself. Round and smooth slides better than pointy and edgy. Helmet makers have improved on this front in recent years.

Helmet size and mass

All other things being equal, concussion risk is lower with a lighter, smaller helmet. Just like a heavier hammer is better at driving nails than a lighter one, a heavier helmet will whip your hapless noggin into the rocky earth that much harder than a light helmet will. And a bigger helmet will yank your head harder in a crash, the same way a long prybar works better than a short one. But a shower cap is small and light and it won't help you much in a crash. Size and mass can be a trade-off, as I mentioned above in talking about single- vs. double-shell designs. As consumers, we simply don't have the data to know how to balance the costs and benefits of the different designs.

Fit

Helmet fit matters too, at least to an extent. If your helmet fits so badly that it bounces around in a crash and leaves useful parts of your head exposed, that's ain't good. But many internet geniuses insist that helmet fit is The Only Thing That Matters By God, and I disagree. If my choice were between a perfect-fitting IXS Trigger and a good-enough-fitting Leatt DBX 3.0, for example, I'd take the Leatt in a heartbeat.
 

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Discussion Starter #20
Everything else

Crash replacement

Wild unproven keyboard-warrior theory: a non-MIPS helmet with a terrific crash-replacement policy is safer than a MIPS helmet with a "sorry dude buy a new one" replacement policy. Scandalous, I know. But we all know damn well that nobody replaces a month-old $150+ helmet after a crash unless the helmet broke so badly that they aren't able to find enough pieces to duct-tape it back together. Unless you're an orthodontist, good crash replacement policies (Kali's is the hands-down best, Bontrager has a decent one too) are a real helmet safety feature.

Oh and besides the obvious benefit, they also give the maker a gold mine of actual crashed helmets to test. Who do you trust more, the company that wants to learn from real-world crash data or the one that doesn't? I was intrigued by POC's Spin and I thought the teal color they had last year was high MTB style, but the lack of a crash-replacement policy was a deal-breaker for me.

Venting and comfort

If you're overheating, you're more likely to crash. If a raging torrent of sweat is pouring into your eyes, you're more likely to crash. If you're distracted by an uncomfortable helmet, you're more likely to crash. And the more you crash, the more likely you are to concuss yo self. So it stands to reason that, all things being equal, a cooler, comfier helmet will be safer. Once again, how that plays out in the real world is anyone's guess.

Everything else

In the wise and wacky words of Don Rumsfeld, past the known unknowns are the unknown unknowns. It would be surprising if we've already identified all the factors that significantly impact concussion risk.
 
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