Below the Brim: What Helmets Don't Fix

Every rider who competes in a sanctioned horse show in the United States wears an approved helmet. It is required. The helmet bears a certification sticker -- ASTM/SEI, the shorthand for a standard first published in 1990 -- and the rider trusts, reasonably, that the object strapped to her head has been engineered to protect her. She may have spent three hundred dollars on it or six hundred. She may have chosen it for the MIPS liner, the rotational-protection technology marketed as a breakthrough in concussion prevention. She rides, she falls, she gets up, she adjusts the chinstrap, and she gets back on. The helmet did its job. The conversation ends there.

Except the research suggests it should not.

What the standard actually tests

ASTM F1163 -- the standard to which every equestrian helmet sold in the United States must conform -- was first published in 1990 and is reviewed every five years. The test protocol requires four impacts: the helmet is dropped from approximately six feet onto anvils of varying shapes and angles, including a flat steel surface and a sharp-edged steel surface. The helmet must keep peak linear acceleration below 250g. It is also tested for retention -- the chinstrap must hold -- and visor flexibility. Each test is performed after the helmet has been frozen, heated, and submerged, to ensure it performs across environmental conditions.

What the standard does not test for is the way most riders actually hit the ground.

In 2020, a collaborative team from University College Dublin and the University of Ottawa, led by J. Michio Clark, published a study in the Annals of Biomedical Engineering titled "Equestrian Helmet Standards: Do They Represent Real-World Accident Conditions?" The answer, supported by reconstructions of actual equestrian falls, was no. The study found that real-world concussive equestrian impacts occur from oblique falls onto compliant surfaces -- turf, arena footing, sand -- at forces well below the 250g threshold and over durations longer than the sub-15-millisecond impacts the standard measures. Concussive equestrian accidents, Clark's team found, typically produced peak linear accelerations below 130g over impacts lasting more than 20 milliseconds. The standard tests for a high-magnitude, short-duration impact on steel. The sport produces low-magnitude, long-duration impacts on earth.

Clark's research group, in a companion study published in the Journal of Science and Medicine in Sport, proposed equestrian-specific concussion thresholds based on video reconstruction of 50 falls -- 25 concussive, 25 non-concussive. The resulting 50-percent-risk threshold was 59g: a force level that the current certification standard does not consider a meaningful impact. A helmet that passes ASTM F1163 has been proven to protect a rider's skull from a catastrophic linear blow. It has not been proven to prevent a concussion from the kind of fall that actually happens in a riding arena.

The MIPS question

The Multi-directional Impact Protection System -- MIPS -- has been the most commercially successful helmet-safety innovation in equestrian sport in the past decade. The technology, originally developed in Sweden, adds a low-friction liner inside the helmet shell that allows the head to rotate slightly on impact, intended to reduce the rotational forces associated with concussion. Helmet manufacturers market MIPS as a significant safety upgrade, and riders routinely pay a premium for it.

In 2025, Sara Gould and colleagues at the University of Alabama at Birmingham's Equestrian Sports Medicine Collaborative published a study in the Clinical Journal of Sport Medicine that tested the proposition directly. The researchers surveyed 357 collegiate equestrians and compared head injury outcomes across helmet types. The finding was unambiguous: the risk of head injury did not differ significantly between riders wearing helmets with MIPS and those without it. Neither helmet brand nor liner type was associated with a lower rate of head injury.

This is not an argument that MIPS is useless. In controlled laboratory conditions, rotational-impact liners can reduce peak rotational acceleration. The Virginia Tech Helmet Lab, in a 2025 study published in the Annals of Biomedical Engineering, tested 45 equestrian helmet models with 720 impact tests -- the largest published study on equestrian helmets to date -- and incorporated oblique testing into its STAR rating system for the first time. But there is a difference between a laboratory demonstration that a liner can reduce a measured force and a real-world finding that the liner reduces injury. The UAB study measured the latter. The answer was no significant difference.

The implication is not that riders should abandon MIPS or stop buying well-rated helmets. It is that the sport has treated helmet technology as a proxy for concussion prevention -- and the evidence does not support that substitution. The concussion problem in equestrian sport is real. But it is not primarily a problem of engineering.

The scale of the problem

Equestrian sports are the leading cause of sport-related traumatic brain injury among adults treated at United States trauma centres, according to a 2016 analysis of the National Trauma Data Bank led by Ethan Winkler and colleagues at the University of California, San Francisco, published in Neurosurgical Focus. The study examined sport-related TBI admissions from 2003 to 2012 across five sporting categories and found equestrian activities accounted for the largest share.

A 2023 study by Beth Glace and colleagues, published in the Journal of Science and Medicine in Sport, was the first to calculate concussion incidence rates in equestrians. The researchers surveyed 210 riders and found a lifetime total of 728 concussions -- an average of 3.47 per rider. The incidence while riding was 0.19 per 1,000 hours, higher than the incidence during football or rugby training. Riders were helmeted 85 percent of the time they sustained a concussion.

That last figure deserves emphasis. Eighty-five percent of equestrian concussions happen to riders who are wearing approved, certified helmets. The helmets are on. The concussions are still occurring. If helmet availability were the primary driver of concussion risk, that number would be much lower. Instead, it suggests that the factors driving equestrian concussion are ones the helmet is not designed -- or, under the current standard, not tested -- to address.

The culture below the brim

The UAB study revealed something that anyone who has spent time at a horse show already knows. Seventy-eight percent of collegiate riders said they would not replace their helmet after every fall. This is despite the unambiguous recommendation from every helmet manufacturer that a helmet must be replaced after any impact -- even one that appears minor -- because the expanded polystyrene liner that absorbs energy on impact can only do so once. A helmet that has taken a blow may look intact. Its protective capacity may be compromised.

The general guidance is replacement every three to five years from first use, regardless of whether the helmet has been involved in a fall. UV exposure, sweat, temperature fluctuation, and the natural degradation of materials all reduce a helmet's protective properties over time. Yet riders routinely wear helmets for five, seven, ten years, replacing them only when the velvet wears through or the fit loosens -- cosmetic cues, not safety ones.

More concerning still: more than half of the riders in the UAB study who reported sustaining a concussion said they never sought medical treatment. This finding is consistent with earlier research in the field, which has repeatedly found that a majority of equestrians who self-report concussion symptoms do not seek formal medical evaluation.

The culture of the sport teaches riders that falling is part of riding and that getting back on is a measure of character. That ethos has value -- resilience and courage are not trivial qualities. But it has also produced a generation of riders who treat a concussion the way they treat a bruise: something to ride through, not something to report. USEF now requires that any rider suspected of a concussion at a licensed competition must receive medical clearance before competing again, following a staged return-to-sport protocol developed in alignment with the 6th International Concussion in Sport Consensus Statement. The FEI prohibits same-day return to riding and mandates a six-stage recovery process. These are meaningful rules. They apply only when someone identifies the concussion in the first place -- and the evidence suggests that, more often than not, the rider herself decides it was not one.

What is changing

There are signs that the science is beginning to close the gap. US Equestrian has partnered with the Children's Hospital of Philadelphia's Center for Injury Research and Prevention to fund equestrian-specific concussion research. The initiative, led by Kristy Arbogast, the centre's scientific director, and supported by the clinical insights of Christina Master, a paediatric sports medicine specialist at CHOP, has raised $400,000 toward a $700,000 goal. CHOP treats approximately 5,000 children per year for concussion injuries across all sports; its equestrian research arm is working to develop the discipline-specific data the sport has lacked.

The Virginia Tech Helmet Lab's updated STAR rating system, released in April 2025, represents a genuine methodological advance. Developed by Steven Rowson's Virginia Tech Helmet Lab, the system now incorporates oblique drop testing alongside the traditional linear protocol. The study behind it -- 45 helmet models, 720 impact tests, the largest equestrian-helmet dataset ever published -- gives riders and manufacturers the first comprehensive comparative measure of how helmets perform under conditions that more closely approximate real-world falls. The FEI has publicly advocated for testing protocols that evaluate both linear and rotational impact criteria, a position that aligns with the direction the Virginia Tech research is moving.

These are real advances. But they address the science of the helmet, not the behaviour of the rider. A better test standard will produce a better-performing helmet. It will not make a rider replace her helmet after a fall she classified as minor. It will not make her report a headache to the show medic instead of riding her second round. It will not close the gap between what the rule says -- medical clearance required -- and what the culture permits.

The argument

Helmets save lives. This is not in dispute. The evidence that equestrian helmets prevent skull fractures and reduce the severity of traumatic brain injury is well-established. The Glace study's finding that helmeted riders sustain concussions at rates higher than those reported in emergency-department data -- where helmet use at the time of injury is far lower -- suggests that helmets effectively prevent the most severe concussions, the ones that would otherwise send a rider to hospital. That is a meaningful form of protection.

But the industry has blurred the line between preventing catastrophic head injury and preventing concussion. These are different problems with different mechanisms. The certification standard addresses the first. Neither the standard nor the current generation of helmet technology has been shown, in real-world outcomes, to address the second. And the sport's cultural response to concussion -- normalise the fall, dismiss the symptoms, ride the next class -- compounds the gap.

A safer sport requires three things the industry has not yet delivered: a certification standard that tests for the oblique, compliant-surface impacts that cause most equestrian concussions; enforcement of return-to-ride protocols at every level of competition, not only at rated shows with medical personnel on the grounds; and a cultural shift that treats every fall as a potential medical event -- not a character test. The technology will follow the standard. The standard must follow the science. And the science is already ahead of both.

The next time you walk out of the arena after a fall and reach up to adjust the chinstrap, ask yourself two questions. When did you buy this helmet? And when was the last time you hit the ground in it? If the answer to the second question is today, the helmet has done the only job it can do. It needs to be retired. And you may need to see a doctor before you see the in-gate again. No liner technology replaces either of those decisions. Those are yours.