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Too Many Opinions, Too Little Expertise: Why the Head Protection Debate Is Failing Players

Too much of the head protection debate is being driven by non-expert noise and repeated outdated assumptions, rather than specialist insights and newer knowledge.

The loudest critics rely on old assumptions, old evidence, and superficial talking points; not on a serious and detailed understanding of biomechanics, physicality of the brain, brain injury, neurodegeneration, and wider brain health knowledge. That matters because this is not a trivial argument. It is about how seriously sport is prepared to take brain protection and how the wider public is becoming more educated and informed on brain protection.

With every head impact, the brain moves inside the skull. The brain can move in a linear plane or rotate inside the skull. The rotational motion really matters as this is associated with the tearing of tiny blood vessels and brain cells resulting, over time, in the breakdown of the protective blood-brain barrier and the creation of damaging neuro-inflammation. This shearing sequence arising from rotational forces needs to be understood over the generalised and inaccurate description of the brain sloshing around or banging against the skull. Also what needs to be better understood is that the neuro-inflammation from rotational forces is a common feature in neurodegenerative diseases like CTE (an early onset dementia), MND, and Parkinson’s disease.

Rotational forces are present in every concussion and sub-concussion, the more frequent, smaller-force head impacts that cause no concussion symptoms but still damage the brain. Cumulative rotational force and sub-concussive damage to the brain matters; it is a case of how little is too much, not how much is too much. Any serious brain protection discussion has to start there [1].

Modern brain protection should be judged on modern biomechanical testing, sophisticated neuroimaging and framed around what the science is increasingly showing about the longer-term neurodegenerative effects of repeated sub-concussive head impacts and rotational forces; not on recycled myths based on conventional rugby headgear that World Rugby itself makes clear was designed to reduce cuts and abrasions, not mild traumatic brain injury [2] or hard shelled helmets that are designed to protect the skull from acute injury. The efficacy of headgear should be judged on more than the crude binary understanding and outcome of “concussed or not”, and newer brain protection products must be reviewed in context from other classes of headgear.

The head protection debate is full of noise, not expertise

Public discussion, media coverage and non-expert debate keeps collapsing a complex issue into an unhelpful simple conclusion: either a product completely prevents concussion, or it “doesn’t work.”

That is not how biomechanics works. It is not how brain injury and the triggering of neurodegenerative consequences works. It is not how protective measures work.

The more intelligent questions are whether a product reduces rotational forces transmitted to the brain during concussive and sub-concussive impacts; and whether those reductions matter enough to reduce the potential risk of triggering longer-term neurodegenerative consequences. That is where serious brain protection expertise and understanding sits. It is also where much public commentary and understanding falls apart.

Over the last decade, advanced neuroimaging research has been focused on the subtler effects of repetitive sub-concussive head impacts because standard clinical scans miss this damage. Yet too few are aware of this sophistication in neuroimaging and the protective interventions needed to reduce the white matter damage deep within the brains of contact and collision sports players [3, 4].

Rezon Halos® brain protection worn in professional women's football.

Much of the criticism attacks products that were never designed to protect the brain

This is the flaw at the centre of many anti-headgear arguments.

Critics frequently lean on evidence about traditional rugby scrum caps, legacy soft headgear or hard-shelled helmets. But World Rugby’s own specification makes their purpose clear: their approved headgear was intended to reduce the risk of cuts and abrasions, with any impact reduction properties secondary to that aim [2]. Its player guidance likewise states there is no evidence that such headgear protects against concussion [5].

That matters because it means much of the criticism is aimed at products that were never designed, intended, tested, or approved as brain protection in the first place.

It is entirely fair to say conventional headgear was not built to solve mild traumatic brain injury. What is not fair is to use that fact to dismiss and tar with the same brush a fundamentally different new category of modern protective product designed around rotational force reduction and sub-concussion protection, and independently tested on that basis [1, 6].

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Myth-busting – the claims that refuse to be corrected

Myth 1: “Head protection doesn’t work and isn’t the answer.”

This is far too broad to be taken seriously.

Not all protection is the same. Not all products are designed the same way. Not all products are tested in the same way.

Virginia Tech’s peer reviewed STAR methodology exists precisely because pass/fail certification alone does not show how products compare in reducing head loading. Its ratings are based on sports-specific testing that measures linear and rotational acceleration and estimates relative concussion risk. More stars indicate better relative performance in the tested scenarios [7].

That means blanket claims that “head protection doesn’t work” are unsustainable and untrue. Comparative performance can be measured. Differences can be identified. Better and worse products can be distinguished in a public rating framework.

Virginia Tech’s ratings efficacy also go beyond biomechanical testing, and too few are aware of the real-life testing of different rated Virginia Tech products. Virginia Tech only recommends 4 or 5-star products as being effective. A 2019 study involving almost 3000 players showed that the top performing 5-star products achieved a statistically significant reduction in relative concussion risk (~60% reduction in risk ratio) [8]. As another data crosscheck to Virginia Tech only recommending 4 or 5-star products as being effective, no World Rugby-approved headguard has a public 4 or 5-star rating.

Rezon Halos® achieved a 5-star Virginia Tech rating in 2021, with published testing showing up to a 61% reduction in rotational acceleration and a 74% reduction in concussion risk under the Virginia Tech framework [6]. That is not proof that every downstream neurodegenerative protective outcome has been evidenced. But it is meaningful evidence that Rezon Halos® should not be lumped together with older, generic and ineffective headgear in the market.

Myth 2: “It creates a false sense of security.”

This phrase is repeated constantly, and too rarely examined properly.

Some governing-body materials have raised concern that headgear could encourage risk-taking behaviour [5]. But concern is not the same as proof. Belief is not the same as behaviour; and behaviour is not the same as injury outcome.

The stronger and more accurate point is this: there is no robust causal evidence showing that wearing headgear increases dangerous behaviour and therefore increases brain injury risk. In sports where concussion mitigation has become a major issue, such as Australian Rules football and football (soccer), the wearing of headgear has not appeared to have changed players’ behaviours [9, 10]. The confidence-risk claim is often stated more strongly than the evidence allows, and too often used to close down discussion rather than improve it [5, 11].

Myth 3: “Helmets don’t work either.”

This is another stale line that confuses anything less than perfection with failure.

Protective design improves. Materials improve. Testing improves. Standards improve. The fact that older products had limitations is not an argument against innovation; it is the reason innovation matters.

Virginia Tech’s ratings reflect that reality. Their purpose is to distinguish relative protective performance between products rather than treating all compliant products as equivalent [7]. That should not be controversial. It is exactly what serious product development should produce: measurable improvement over time.

A 2022 longitudinal study in Annals of Biomedical Engineering strengthens this point; high-school football players wearing newer, higher-ranked helmets did not show the same relationship between frequent high-magnitude head impacts and the degree of cortical thinning seen in players wearing older, lower-ranked helmets, suggesting via sophisticated neuroimaging evidence that improved helmet design does buffer the brain against cumulative effects of repetitive impact exposure [13].

A hard-shelled helmet is designed to reduce acute injury, but is not suitable for every sport, and in some sports the wearing of a helmet would further increase brain injury risk by allowing higher-force impacts and more rotational forces transmitted to the brain.

Myth 4: “Concussion is the main issue.”

Concussion is the visible issue, but cumulative sub-concussive brain load is the deeper long-term problem. Concussion is not the whole or main issue.

The more serious long-term brain injury concern is cumulative sub-concussive exposure; repeated small-force impacts that do not trigger concussion symptoms, but still damage the brain.

There is also no single, clear biomechanical threshold at which an impact becomes “a concussion” and everything below it becomes harmless. Recent commentary in the British Journal of Sports Medicine argues that some impacts greater in magnitude than diagnosed concussive impacts may produce no symptoms at all, which further weakens the idea that concussion is the only meaningful marker of neurological damage [14].

CTE, the progressive neurodegenerative disease found in former amateur and professional sports players, is driven by repeated sub-concussive impacts and rotational forces – not simply by diagnosed concussion events.

That is why the old question; “does it stop concussion, yes or no?”; is too narrow and underscores an absence of understanding of the now-known spectrum of neurological injury.

The real problem is cumulative damage to the brain, which is why reductions in rotational force transmission matter precisely because they accumulate [1, 3]. Marginal reductions in rotational forces and sub-concussive damage accrued from early childhood sport and across a lifetime of playing will lower the overall cumulative load to the brain and contribute to reduced risk of triggering neurodegenerative consequences.

What we actually know now

We know far more than critics of headgear will admit.

We know rotational forces are the primary driver of brain injury in sport [1].

We know repetitive sub-concussive exposure is a serious concern beyond diagnosed concussion [3].

We know standard brain imaging lacks the sensitivity to identify subtle injury deep inside the brain.

We know sophisticated imaging techniques do reveal changes in the brain ahead of neurological symptoms [4].

And we know independent comparative biomechanical and field testing does identify meaningful differences in headgear product performance [7].

This is not a debate taking place in the absence of evidence. It is a debate too often distorted by people still arguing from an outdated evidence base, or demanding proof of perfection before accepting the possibility of technological advance.

Rezon Halos® head protection worn to reduce concussion risk in netball.

What a Virginia Tech 5-star rating actually means

A Virginia Tech 5-star rating is not a guarantee. It is something more useful: an independent comparative signal.

Virginia Tech states that its ratings identify which helmets or headgear best reduce concussion risk in laboratory testing. It does this through sport-specific impact testing that measures both linear and rotational acceleration [7]. That matters because it goes beyond basic governing body testing standards and helps distinguish relative protective performance between products.

So when Halos® achieves a 5-star rating, the correct conclusion is not that all questions have been answered forever. The correct conclusion is that this product sits in a different evidential category from conventional headgear that was never designed around brain protection and has no equivalent testing position [2, 6, 7].

Rezon Halos® being tested using the Virginia Tech Helmet Labs STAR methodology.

Why rotational force reduction matters in modern brain protection

Design intent matters because injury mechanism matters.

If brain injury risk is strongly linked to rotational motion and cumulative damage of sub-concussions, then a product specifically designed to reduce rotational force transmission is more relevant than one designed primarily to reduce cuts to the scalp or damage to the ears [1, 2], or one that focuses on linear force/impact reduction. That is basic logic.

It is also why rotational force reductions should not be brushed aside. In a cumulative exposure problem, marginal gains are not trivial. Rotational forces and sub-concussions compound over seasons, training sessions, school sport years, amateur participation, and long playing careers [3]. A debate focused only on the single concussion event misses the arithmetic of repeated small-force impacts. Sub-concussions are 500 times more frequent than concussions in sport, yet only concussions are considered relevant [12].

Why advanced neuroimaging will prove the efficacy of brain protection

The next phase of the evidence debate will not be settled by marketing slogans about ‘impact reduction’ or the loudest voice in an ongoing debate. It will be settled by seeing more clearly what repeated sub-concussive impacts and cumulative rotational forces do to the brain over time, and how products reduce this.

That is where advanced neuroimaging matters and is now coming to prominence. More advanced techniques such as diffusion tensor imaging, susceptibility-weighted imaging, functional MRI, and magnetic resonance spectroscopy are being studied because they can detect the subtler microstructural, metabolic, and functional brain changes that conventional scans miss [4].

Over time, this will strengthen the evidence base of headgear products significantly. The future proof point will not be the crude binary of “concussed or not”, or biomechanical lab testing. The neuroimaging evidence will provide the gold standard of evidence on product efficacy.

The evidence bar has been set unrealistically high on brain protection

One of the strangest features of this current protective headgear debate is the standard that critics demand.

Brain protection is often expected to deliver perfect proof, total elimination of risk, or decades of definitive field-outcome data before innovation is even taken seriously. Yet comparative product testing already distinguishes better from worse performance within tested conditions [7]. In most other areas of health, safety, and performance, iterative improvement and marginal gains are treated as meaningful. Why should brain protection be held to an impossible all-or-nothing protective standard before evidence-led innovation is even allowed into the conversation? Or be offered as a protective option to players or a safety product adopted by schools?

The sensible question is whether advances in design can reduce harmful rotational force exposure and plausibly reduce cumulative brain load over time. The evidence so far suggests that is exactly the right question to ask of any brain protection [3, 6, 7].

It is time to decide what side of this protection debate you are on

Either reducing rotational forces and sub-concussive damage will reduce cumulative brain load and neurodegenerative consequences, or it will not. The medical expert knowledge and the current biomechanical and neuroimaging direction of travel strongly suggests that it will [1, 3, 4].

Waiting for perfect protective proof of a product means continuing to accept avoidable exposure in the meantime. That is not neutrality. It is a stark decision choice when we know that no brain protection results in reducing an individual’s cognitive reserve and triggering longer-term neurodegenerative consequences. Children will not thank their parents, coaches, clubs and schools in a few years for permitting them today to sustain a higher level of rotational forces and sub-concussions than was necessary, and hide behind the excuse of not enough proof was available or it was not mandated. Perfect really is the enemy of good in this instance.

Until the evidence proves this one way or another, choose carefully the brain protection decision for you, your children, your pupils and your players. Choose it with knowledge. Choose it with an understanding of what the brain is, the nuance of how it moves, what cumulative rotational forces and sub-concussive damage means and does to brain health, and what modern comparative testing and evidence of individual products actually shows. But do not choose it based on outdated products, obsolete assumptions, simplistic media reporting, superficial recommendations, and the fog-horn certainty of non-clinical experts who have never seriously engaged with neuroscience or understand it at the most detailed level.

Sports players at every age and stage really do deserve better than recycled myths on protective headgear and an excuse of not enough evidence exists. They deserve a product debate informed with expertise, evidence, and a genuine commitment from those with a legal duty of responsibility (parents, teachers, coaches) to protecting the brain beyond a concussion focus.

Rezon is leading this debate globally with access to unrivalled knowledge, insights and expertise. This is why we are speaking up now to say enough: a much more intelligent debate around brain protection needs to happen, those with a duty of care need to wake up on the evidence and science, and every sports player needs to have the option today to protect their brain and reduce their risk of facing the potential outcome of neurodegenerative disease.

Ignorance is no longer an excuse. Former professional and amateur players are already forcing sport to confront what was known about brain health risk, and what more could have been done. The children playing today will one day ask the same question of parents, schools, clubs and coaches: why were they not warned, and why was avoidable exposure accepted when better information was available? The evidence is no longer hidden. The responsibility now is to act on it.

  1. Brain protection technology for sport | Reducing rotational force. Further Reading. Rezon.
  2. Headgear Specification. World Rugby.
  3. A Comparative Neuroimaging Review of Repetitive Head Impacts. Bell NM et al.
  4. Neuroimaging of Mild Traumatic Injury. Capriotti G et al.
  5. Equipment, Environment and Emergency Plan. World Rugby Passport.
  6. Our laboratory testing for Halos®. Further Reading. Rezon.
  7. Virginia Tech Helmet Ratings. Virginia Tech Helmet Lab.
  8. Can helmet design reduce the risk of concussion in football? Rowson S, Duma SM, Greenwald RM, et al. Journal of Neurosurgery. 2014;120(4):919–922
  9. The association of padded headgear with concussion and injury risk in junior Australian football: A prospective cohort study, Knight JM, Mitra B, McIntosh A, Howard TS, Clifton P, Makdissi M, Rosenfeld JV, Harcourt P, Willmott C, 2022
  10. Does soccer headgear reduce the incidence of sport-related concussion? A cluster, randomised controlled trial of adolescent athletes, McGuine T, Post E, Pfaller AY, et al, 2020
  11. Safety Helmets; Efficacy in Reduction of Head Injuries in Recreational Skiers and Snowboarders. Eastern Association for the Surgery of Trauma.
  12. Leveraging football accelerometer data to quantify associations between repetitive head impacts and chronic traumatic encephalopathy in males, Daneshvar DH, Nair ES, Baucom ZH, Rasch A, Abdolmohammadi B, Uretsky M, Saltiel N, Shah A, Jarnagin J, Baugh CM, Martin BM, Palmisano JN, Cherry JD, Alvarez VE, Huber BR, Weuve J, Nowinski CJ, Cantu RC, Zafonte RD, Dwyer B, Crary JF, Goldstein LE, Kowall NW, Katz DI, Stern RA, Tripodis Y, Stein TD, McClean MD, Alosco ML, McKee AC, Mez J, 2023
  13. Helmet Technology, Head Impact Exposure, and Cortical Thinning Following a Season of High School Football. Dudley JA et al. Annals of Biomedical Engineering. 2022;50:1608–1619.
  14. ‘Subconcussive’ is a dangerous misnomer: hits of greater magnitude than concussive impacts may not cause symptoms. Nowinski CJ, Rhim HC, McKee AC, et al. British Journal of Sports Medicine. 2024;58(14):754–755.

Author: Judith McMinn

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Judith McMinn is the CEO and Founder of Rezon. She had identified something missing from sports. While traditional protective headwear focused on the head and skull, there was nothing effectively protecting the brain. So, she developed brain protection in sport, Halos®.

Read more articles by Judith McMinn

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