SCIENCE BEHIND

Equine Hanna Somatics® (EHS)

What is POSTURE?

Abnormal or Maladaptive Compensatory Posture

Posture is an unconsciously mediated adaptive process of the nervous system that organizes the body as best it can to remain upright and in equilibrium against gravity and environmental factors, moment by moment, within the range of motion allowed by the current levels of resting myofascial tone. (Mayer 2013)

As horses adapt to their environment, they learn to keep various muscles habitually contracted, creating persistent areas of elevated resting myofascial tonus (aka tension).

It is this persistent tension that pulls the horse out of his or her natural alignment, creates postural patterns, and negatively impacts movement, soundness and well-being.

And once it's learned, it becomes the 'new normal' default posture that is maintained by involuntarily mediated motor output coming from the brain stem...

PHOTOS: Horses who presented with various examples of the characteristic maladaptive compensatory habitual postures typically reversible with Equine Hanna Somatics® Education.

REFERENCES

Cacciatore, T. W., Anderson, D. I., & Cohen, R. G. (2024). Central mechanisms of muscle tone regulation: implications for pain and performance. Frontiers in neuroscience, 18, 1511783. https://doi.org/10.3389/fnins.2024.1511783

Criswell, E. & Mayer, A. (2006-2025) Equine Hanna Somatics® Professional Training Program Manual

Hanna, T. (1988) Somatics - Reawakening the Mind’s Control of Movement, Flexibility and Health. Da Capo Press

The PROBLEM

Chronic tension is a natural adaptive response to stress, trauma and repetitive motion. Manual therapy, stretching and strengthening or conscious efforts at controlling posture or 'relaxing' do not address the centrally controlled 🧠 nervous system complexities underlying muscle tone...(Cacciatore et al. 2024)

Vets, bodyworkers, physiotherapists, riders and trainers have always known relaxation and 'releases' were essential, but they were impossible to define, explain or access on demand. UNTIL NOW.

What is PANDICULATION?

Pandiculation, nature's postural reset.

Pandiculation is a natural behavior that contributes to the development and maintenance of a horse's neuromuscular integrity and mind-body integration at all ages and stages of life.

All animals spontaneously pandiculate, typically after a period of inactivity like sleeping or being confined.

Pandiculation can be done standing or laying down (ie. recumbent), and looks like a symmetrical full-body stretch, often accompanied by a yawn - or it can involve just one or two limbs at a time, or one limb and the neck, or wing… there are many variations on the ways different animals pandiculate.

Foals even pandiculate in their mother’s womb, and have been observed pandiculating up to 80 times per day after being born, as soon as on their 3rd day of life!

PHOTO: Aged Arabian mare demonstrating a spontaneous pandiculation reflex.

REFERENCES

A.F. Fraser, Pandiculation: the comparative phenomenon of systematic stretching, Applied Animal Behaviour Science, Volume 23, Issue 3, 1989, Pages 263-268, ISSN 0168-1591, https://www.sciencedirect.com/science/article/abs/pii/0168159189901172?via%3Dihub

Bertolucci L. F. (2011). Pandiculation: nature's way of maintaining the functional integrity of the myofascial system?. Journal of bodywork and movement therapies, 15(3), 268–280. https://doi.org/10.1016/j.jbmt.2010.12.006

McGreevy, P. (2012). Equine Behavior, A Guide for Veterinarians and Equine Scientists (2nd ed.) Saunders Elsevier

The SOLUTION

Dr. Eleanor Criswell Ed.D. created Equine Hanna Somatics® (EHS) - a hands-on method of helping horses change their own default posture by resetting their resting myofascial tonus (aka chronic tension) back to NORMAL NEUTRAL LEVELS.

EHS is horse-centric somatic education based on the principles of basic neuroscience and the natural tendency of horses to pandiculate.

VOLUNTARY PANDICULATION

EHS is Pandiculation ON-Demand

Instead of treating the horses body manually, we invite the horse to actively participate in the EHS movements, which allows us to work directly with the root-cause of most muscular tension - the brain and the way it organizes the body for movement.

By working WITH the horse's brain to engage the Pandicular Response on-demand, we can access the existing pathways and programs of the horse's nervous system to efficiently target areas of habitual tension - and facilitate the horse in normalizing them from the inside.

Equine Hanna Somatics® is the only system that teaches you how to safely and reliably harness the power of Pandiculation to help horses effect rapid and permanent changes ​to their own baseline levels of muscle tension.

ILLUSTRATION: ©2013 Horse Brain by Barbara Chasteen, from Equine Hanna Somatics - Session 1 (introductory course)

REFERENCES:

Criswell, E. (2021) How Eleanor Criswell Created Equine Hanna Somatics (originally published 1997, Somatics Magazine: Journal of the Bodily Arts and Sciences) https://blog.equinehannasomatics.org/post/creating-equine-hanna-somatics

Hanna, T. (1990) Clinical Somatic Education: A New Discipline in the Field of Healthcare. Somatics Magazine: Journal of the Bodily Arts and Sciences, 4-10.

Before we can accurately assess conformation, asymmetry, soundness, strength or behavioral issues, we must identify and address the involuntary habitual tension that is pulling the horse out of alignment and creating the persistent postural deviations, functional weakness and crookedness everyone is trying to correct.

Characteristic Equine Postural Presentations

The most common maladaptive compensatory postures are caused by habituated stress-responses, which typically present in one of three easily recognizable postural patterns:

The Green Light Reflex

The Green Light Posture shows up when a horse is startled, afraid or excited, and is commonly known as "fight or flight." This is the Startle/Action Response.

Habitual contractions above the vertebral column produce spinal extension, downward pressure on the thorax, a camped out limb position, and...

The Red Light Reflex

The Red Light Posture shows up when a horse is withdrawing from their reality, usually because they cannot escape confinement or pain, and is commonly referred to as "shut down" or "introverted." This is the Withdrawal Response.

Habitual contractions below the vertebral column produce spinal flexion, a camped under limb position, and...

The Trauma Reflex

EHS Equine Trauma Asymmetry Posture

The Trauma/Asymmetry Posture (ie. crookedness) is often mistaken for laterality or "natural asymmetry" and it shows up when a horse is contracting the muscles on one side of their body more strongly than the other. This is an Antalgic (pain-avoidance) Response involving the withdrawal and crossed-extensor reflexes that becomes habituated, or is learned from repetitive motion or asymmetrical bracing...

"The role of Equine Hanna Somatics® is to help a horse's brain recognize inefficient and unconscious muscle contractions that are no longer useful, so they can regain conscious control over their own muscles and, therefore, also regain access to their full range of motion, comfort, strength and endurance.”

- Alissa Mayer, Director of the EHS Professional Training Program

BENEFITS

Case Studies and Published Research

Cognitive Enhancement

Athletic Performance

Injury Prevention

Real-life stories and studies that show the benefits of Hanna Somatic Education on body & mind.

EHS Trauma/Asymmetry Posture horses

Equine Trauma / Asymmetry Posture

November 07, 20258 min read

Most horses aren't crooked, they're contracted!

And the reason your horse isn't getting better is because very few equine professionals (yet) understand where the majority of asymmetry is coming from (SPOILER: it's learned via habituation), so they don't know what to do about it (SOLUTION: it must be changed in the horse's brain, where it was learned - which only the horse can do, from within).

“All truth passes through three stages. First, it is ridiculed. Second, it is violently opposed. Third, it is accepted as being self-evident.” — Arthur Schopenhauer (1788–1860)

The truth is that manual therapy, veterinary interventions, alternative treatments, PT, postural rehabilitation exercises and 99% of training methods simply do not affect the part of the central nervous system that is maintaining habitual (aka learned) myofascial tension... so most ‘treatments’ only produce temporary results that must be repeated and/or strengthened with supportive exercises, and still the tension just keeps coming back, often for years.

Equine Trauma Asymmetry Reflex Posture by Alissa Mayer

Crookedness is so persistent, so common across the global horse industry that it has been accepted as normal (ie. normalized) and chalked up to 'natural asymmetry' or laterality (both of which are very real things, but they are static - meaning they don't change at all for the horse's whole life, they do not go away, but they also do not get better, worse, suddenly appear or self-resolve).

Why are so many Horses Crooked?

The most common cause of crookedness is neither natural asymmetry nor laterality, but is an acquired collection of chronic muscle contractions that pull the horse's body out of it's natural alignment. This abnormal adaptive postural presentation is what we in the field of Hanna Somatic Education® know as the Trauma/Asymmetry Posture.

Trauma/Asymmetry Posture in Horses

It's caused by habitually contracting muscles that result from either the withdrawal and crossed-extensor reflexes, (these happen when we cringe or bend our body to protect a painful area, and/or automatically avoid using/weighting an injured limb), or from simple repetitive movement (training, transport, environmental, antalgic/pain-avoidance, etc.).

The unfortunate truth is that most domestic horses are experiencing some or all of these in their daily lives - whether it's contorting their body to avoid pain or pressure from spurs, bits and pinching saddles, shifting their weight off of sore feet, bracing against applied pressure before they 'give' to it, or balancing against the sway of a moving vehicle...

Horses who have learned to unconsciously maintain the Trauma/Asymmetry Posture as their default resting posture exhibit a unilateral imbalance in resting muscle tone and spinal symmetry. They typically present a characteristic C-curve or S-curve in part or all of their spine, can't comfortably stand 'square' and frequenlty have a whole host of related, mysterious or undiagnosed soundness and behavioral issues.

Because posture is a dynamic natural nervous system process, and habitual posture is learned and maintained by the brain stem and involuntary postural reflexes, it cannot be 'treated' or fixed from the outside, but it can be un-learned from within...

Correcting Asymmetry or Crookedness in Horses

When horses actively participate in slow, deliberate movements, they use the only part of their brain that can change their internally mediated levels of resting muscle tone (the voluntary motor cortex). This happens naturally when horses pandiculate (a spontaneous polysynaptic reflex often described as a 'stretch' that helps the horse reset any accumulated chronic muscle contractions back to normal neutral levels). Normal (neutral) resting muscle tone means that instead of pulling too much on their attachments all the time, the muscles allow the skeleton and fascia to return to their original baseline levels of tension and elasticity - restoring the body's balanced alignment and ability to automatically self-organize and respond efficiently to gravity and appropriately to the environment - aka biotensegrity.

This is what we do in Equine Hanna Somatics®. Using individually tailored protocols of Voluntary Pandiculation, we can systematically help the horse reset their elevated tension levels (that are generated by the muscles and transferred around the body by the fascia), back to neutral.

Voluntary Pandiculation

Voluntary Pandiculation is the innovative technique developed by Thomas Hanna for his ground-breaking somatic work with humans. The technique was named by Eleanor Criswell, and in 1995 she adapted it for working somatically with horses when she created Equine Hanna Somatics (EHS) and Canine Hanna Somatics® (CHS).

Voluntary Pandiculation is an intrinsic activity that horses and other animals do at the invitation and guidance of human somatic educators, and/or that humans can learn to practice on their own, in addition to learn and practice with educated hands-on guidance. It is one of the three techniques used and taught in Hanna Somatic Education®, and is the key to helping clients (of any species) get free from their layers of learned chronic muscle tension.

Learned chronic tension is part of a condition (also named by Hanna and Criswell) called Motor Sensory Amnesia (MSA), that can persist quietly and unconsciously for many years, gradually distorting a horse's healthy posture and movement until it finally becomes restrictive enough to start causing pain or other symptoms.

Reversing Motor Sensory Amnesia

Motor Sensory Amnesia is reversible, and this is how we are helping horses rapidly change from crooked to straight, seemingly overnight!

Straightness doesn't have to be taught or trained, it's the normal state of a healthy horse, frequently hidden under one or more layers of learned muscle contractions, and it only needs to be revealed.

THEN, after a horse is freed from their chronic unconscious muscle tension, we can effectively and efficiently use training to balance out their true natural asymmetry and handedness (aka laterality) to build strength and enhance performance.

Take a look at the case examples below!

Case #1: Roxy, typical "crooked" riding horse is able to reverse 90% of her lifetime's accumulated asymmetry over 10 sessions with a first-year Level 1 Equine Hanna Somatics® Educator!

Equine Hanna Somatics corrects a crooked horse


Top photo (2013), your typical "crooked" riding horse, with a long list of issues, both health and behavioral.

The middle photo is after 3 YEARS of wonderful, biomechnically correct training provided by a skilled and loving guardian (read her story in the original post). What she didn't know was that all that lovely and well-intentioned training was helping to the degree it could by building compensatory strength and muscle contractions in opposition to the existing compensation patterns that had become habituated (aka learned) - but it wasn't changing the underlying self-organization.

In the bottom photo, we finally see this horse's true natural alignment and degree of mild laterality (or congenital asymmetry) after she participated in a few Equine Hanna Somatics® sessions. Finally, she has been freed from her previously learned compensatory muscle contractions that were once useful, but had become maladaptive (ie. they persisted long after the original injury or trauma).

Now, she has full access to all of her muscles because their resting tonus has been reset back to (or toward) a healthy neutral, and that is what her brain stem and postural reflexes are now maintaining as her baseline, default postural pattern.

She is 'straight' because she no longer has layers of learned muscular contractions pulling her out of her natural alignment. THIS is why the subtitle of my ebook introducing EHS to horse-owners is 'the secret to straightness.'

"For the first time, Roxy could hold herself straight and relaxed. Under saddle, she now switches bend effortlessly at the walk without any manipulation from me, just a quiet change in my seat.

We’re not quite there yet in the trot—she still needs a gentle nudge—but I’m hopeful we’ll get there soon. Roxy is 21 and has traveled crooked for a long time creating a lot of issues in her body. It's never too late to start changing."

Floriane Weyrich Level 1 EHSE (and Roxy's owner)

Case #2: Dusty Rose, 27 year old Quarterhorse diagnosed with arthritis self-resolves her compensatory asymmetry (developed over 2-3 years of retirement) after 1 EHS Session!

Asymmetry or Laterality in horses

"Vet diagnosis was arthritis in C7 where nerve innervations for hind end control were pinched off by the arthritis. Dusty was to be retired the year this happened because we noticed stiffness and more difficulty collecting around the barrels (all cues that would have indicated her needing EHS had I know about!). I will say the posture in the before photo progressed after retirement due to her being so camped out right hind, that left front stood forward an away from midline. I never saw her standing square over the last 2-3 years since injury, and now I see her loading right hind all the time, even attempting to rest on it.

Before EHS, her movement was slowing down with increased instability on right hind. She has since tried to out walk me! Stability is better, and I foresee even more improvements with more sessions."

Kristen Nitka Level 1 EHSE (and Dusty's owner)

RESOURCES

Criswell, E. & Mayer, A. (2006-2025) Equine Hanna Somatics® Professional Training Program Manual

Hanna, T. (1988) Somatics - Reawakening the Mind’s Control of Movement, Flexibility and Health. Da Capo Press

Haussler, K. K., le Jeune, S. S., MacKechnie-Guire, R., Latif, S. N., & Clayton, H. M. (2025). The Challenge of Defining Laterality in Horses: Is It Laterality or Just Asymmetry? Animals, 15(3), 288. https://doi.org/10.3390/ani15030288

Krueger K, Schwarz S, Marr I, Farmer K. Laterality in Horse Training: Psychological and Physical Balance and Coordination and Strength Rather than Straightness. Animals. 2022; 12: 1042. https://doi.org/10.3390/ani12081042

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blog author image

Alissa Mayer BSc(Equine) C-EHSE

Alissa Mayer is the Director of the Equine Hanna Somatics Professional Training & Certification Program and founder of the Association for Equine Hanna Somatics Education (AEHSE).

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EHS is not something that can be done TO a horse by the practitioner, but is a voluntary activity the horse engages in - a conversation the horse has WITH their own nervous system.

GET THE INTRODUCTORY ONLINE COURSE:

Equine Hanna Somatics - Session 1

Equine Hanna Somatics® is the only system that teaches you how to harness the powerful natural reflex of Pandiculation to help horses effect rapid and semi-permanent changes ​to their own baseline levels of muscle tension - from within.

Disclaimer: Equine/Canine/Human Hanna Somatics is not bodywork or manual therapy, and is not a diagnostic or treatment tool. The information included on this website and in any affiliated programs is is intended for educational purposes only and is not meant to take the place of professional veterinary or medical advice, may not be current, and is subject to change without notice. We encourage all members of the community to seek guidance from a licensed veterinarian, physician or allied healthcare practitioner regarding specific medical concerns or questions about your own or your animal’s health.

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