Is Rugby Safe? What Neuroscience Says About Repeated Head Impacts and Brain Protection

Are repeated head impacts in rugby dangerous?

Repeated head impacts in rugby create risk because they expose the brain to repeated acceleration and deceleration forces. These head impacts can occur during tackles, rucks, mauls, collisions with the ground, accidental head-to-head contact, and repeated contact during training.

A diagnosed concussion is the visible event. It is the moment when symptoms of a brain injury are recognised: headache, dizziness, confusion, visual disturbance, nausea, memory issues or loss of consciousness.

But concussion is not the whole story on brain injury.

A rugby player will experience sub-concussions far more frequently (hundreds of times more) than diagnosed concussion. These small-force impacts happen repeatedly across training and matches, without symptoms or removal from play. Sub-concussions are head impacts that do not produce symptoms, but they still transmit force to the brain.

The concern is cumulative exposure from concussion and sub-concussion in rugby.

Over a season, a childhood, a school rugby pathway, or a professional career, repeated exposure to head acceleration events becomes biologically meaningful.

Why rotational forces matter in rugby brain injury

Rotational force matters because the brain is vulnerable to twisting motion. Angled impact causes a sudden acceleration and deceleration of the head where the brain moves both in a linear direction and rotates inside the skull.

Rapid acceleration and deceleration of the brain can create mechanical strain in neural, cellular and vascular tissue. In more severe traumatic brain injury, this may involve bleeding, bruising or swelling. In lower-force repeated impacts, the concern is cumulative biological stress, including disruption of neural networks, vascular strain, blood–brain barrier disruption and neuro-inflammation.

In rugby, rotational forces occur in head impacts when a player is tackled, falls awkwardly, is struck on the side or back of the head, or makes head contact with the post or pitch.

This is why modern brain protection cannot be judged only by whether it cushions the outside of the head. The brain injury risk in rugby is not mitigated by protecting the scalp, it is mitigated by reducing the transmission of rotational forces to the brain.

What are the long-term brain-health risks linked to rugby?

The long-term concern for brain health in rugby is not only individual concussion events. It is the accumulation of damage from rotational forces and sub-concussive head impacts over time.

Research on former Scottish international rugby union players found that they had a higher risk of neurodegenerative disease compared with a matched general-population group. The study reported increased risk across neurodegenerative outcomes, including dementia, Parkinson’s disease and motor neurone disease ^[1].

It is important that this is not understood as only a professional rugby problem. Professional players are often more visible because their careers, diagnoses, personal story or legal cases receive media coverage. But the brain injury risk begins wherever repeated sub-concussive head impacts begin; including school, academy, community and amateur rugby.

For most players, exposure to head impacts starts in childhood, long before elite pathways or senior competition. That is why rugby’s brain health conversation cannot focus only on retired professionals or concussion only. It must proactively address sub-concussions with children, parents, schools, clubs and coaches.

This does not mean every rugby player will develop a neurodegenerative condition. It also does not mean that every individual diagnosis can be reduced to a single cause. Conditions such as chronic traumatic encephalopathy (CTE), motor neurone disease (MND), and Parkinson’s disease are complex. But in concussion and sub-concussion there are rotational forces present. These forces can cause the brain to move and deform inside the skull, creating strain in neural and vascular tissue. Over repeated exposure, this mechanical stress contributes to biological processes associated with long-term brain injury, including blood–brain barrier disruption and neuro-inflammation. Neuro-inflammation is a common feature in neurodegenerative diseases like CTE (an early onset dementia), MND, Parkinson’s disease. Rugby can no longer ignore the pattern.

Across contact and collision sports, repeated head impacts are now part of the brain-health conversation. Boston University CTE Center research has linked repetitive sub-concussive head impacts with chronic traumatic encephalopathy, and a 2025 Nature study reported that repetitive head impacts from contact sport are a major risk factor for CTE ^[2].

Rugby has also had to confront this issue in ongoing legal action, and through the lives of players and their families.

Doddie Weir, the former Scotland and British & Irish Lions lock, lived with motor neurone disease and founded My Name’5 Doddie Foundation to fund research into effective treatments ^[3]. Rob Burrow, the Leeds Rhinos and Great Britain rugby league player, was diagnosed with MND in 2019 and died on 2 June 2024 ^[4]. Lewis Moody, former England captain and 2003 Rugby World Cup winner, publicly shared his MND diagnosis in 2025 ^[5].

Players from previous generations are living with consequences that today’s game surely has a responsibility to learn from.

We cannot remove all risk from rugby. But we can reduce avoidable exposure to rotational forces and sub-concussions for the players on school, amateur and professional pitches today.

Why children are at greater risk from rugby head impacts

Children are at greater risk from rugby head impacts because their brains are still developing. Developing white matter is more vulnerable to repeated acceleration events. White matter contains the nerve fibres that connect different regions of the brain. During childhood and adolescence, these networks are still developing, which is why repeated biomechanical stress during this period deserves particular caution.

This matters because the child’s brain is still building the networks that support movement, learning, attention, memory and emotional regulation.

Research in youth American football has shown that children can experience measurable brain changes after repeated sub-concussive impacts in just one season, even without a diagnosed concussion. In one study of players aged 8–13, researchers used diffusion tensor imaging and found white matter tract changes over a single season of youth football in players who did not sustain a clinically diagnosed concussion. ^[6]

This is the invisible risk in contact and collision sports. A child may not report a headache. A coach may not recognise a concussion. A parent may not notice anything unusual after a match. But the absence of symptoms does not equate to the absence of brain injury.

We now know more from research about how the brain responds to rotational forces, than in the past; we know a child is more susceptible to these forces. What we don’t know is which child may have a genetic or metabolic risk factor, which child will continue to play sport at university, into adulthood, or as a professional; so given the damage of sub-concussions and rotational forces are cumulative, the safest approach is to reduce avoidable brain-force transmission from the earliest years of contact sport.

This is why brain protection needs to move upstream in rugby. Waiting for a concussion event before intervening is waiting too long. Brain protection should focus on reducing the transmission of rotational forces to the brain in both sub-concussive and concussive head impacts.

Expert view: why sub-concussive impacts matter

“The risk and severity of CTE is not caused primarily by single big-hit concussions, but by multiple smaller sub-concussive blows to the head and body. Failure to grasp this critical discovery is too common, and presents a huge issue in understanding how to tackle CTE.”

Dr Emer MacSweeney – CTE: The silent killer in contact sports | TEDxAthens ^[13]

Do scrum caps protect the brain?

Traditional scrum caps and rugby headguards are not designed to protect the brain from concussion, sub-concussion, or mild traumatic brain injury.

World Rugby’s headgear specification states that compliant headgear is intended to protect only against cuts and abrasions. It also states that this equipment is not intended or expected to protect against mild traumatic brain injury or skull fracture ^[7].

World Rugby’s Rugby Ready guidance makes the same distinction in practical terms: properly fitted headgear can help prevent soft-tissue injuries to the head and ears only ^[8].

A traditional scrum cap can help reduce the risk of cuts and scrapes to the outside of the head. But that is not the same as protecting the brain from rotational force transmission and should not be confused with reducing brain injury risk.

That distinction matters for parents, players, coaches and schools. World Rugby-approved scrum caps are not designed for brain protection.

What is the difference between a scrum cap and brain protection?

A scrum cap reduces the risk of cuts, scrapes and superficial injury to the outside of the head. Brain protection is concerned with the reduction of rotational force transmission to the brain in concussive and sub-concussive impacts.

That is the category shift.

Traditional rugby headgear has generally focused on surface injury: cuts, abrasions, friction and ear protection. Brain protection must focus on the biomechanics of brain injury: the forces that move, twist or strain the brain during impact.

This is also where different products need to be compared carefully.

N-Pro has published testing showing impact reduction performance. In these independent testing results at Virginia Tech Helmet lab, rotational forces were reduced by an average of 34% across tested speeds and impact sites compared with a bare headform ^[9].

Rezon Halos® Rugby Headguard is brain protection designed to reduce rotational force transmission to the brain. Rezon has been tested to reduce rotational force transmission by up to 61% at the Virginia Tech Helmet lab ^[10]. At every test speed and impact location, Rezon Halos® achieves lower rotational acceleration that N-Pro. Overall, Rezon Halos® outperforms N-Pro.

There is also an independent safety-rating distinction.

Virginia Tech Helmet Lab explains that its ratings identify which products best reduce concussion risk. More stars indicate better protection, and Virginia Tech encourages athletes to choose products rated 4 or 5 stars ^[11].

Rezon Halos® has achieved a 5-star Virginia Tech safety rating ^[12]. No World Rugby-approved scrum cap (including N-pro) has publicly shared a 4- or 5-star Virginia Tech safety rating.

That matters because rugby players and parents need more than governing body approval for match-worn headgear. They need to understand what a product is actually designed and independently tested to do.

Can rugby ever be completely safe?

No collision sport can be made completely safe. However, rugby has a recognised brain injury risk, which can be mitigated with effective brain protection.

Rugby will always involve physical contact, speed, fatigue and unpredictable movement. The realistic goal is not to remove every risk, but to reduce avoidable risk where the consequences are highest. Cut skin and broken bones will heal, but brain injury can have long-term, career-ending, and life-changing consequences. Wearing brain protection in rugby reduces the risk of triggering neuro-inflammation and long-term neurodegenerative disease.