Every single one of us dreams of riding a supple, relaxed, and willing horse. However, when our mount begins to "fight the bit," hollows its back, shortens its stride, or bucks under saddle, our immediate reaction is often to alter the training plan. We think: "The horse has sore muscles," "We need to work on conditioning," or "He lacks flexibility."

Meanwhile, the latest neurophysiological and veterinary research throws a completely new light on this issue. It turns out that it is not physical exertion, but stress, both acute and chronic, that is the most common cause of deep and persistent muscle tension in horses.

Why does this happen? How can we distinguish "training fatigue" from stress-induced blockages, and how can we practically help our horse? Happy reading!

1. Prey Biology: How Stress Paralyzes the Horse's Body

Horses evolved as herd and prey animals. Their survival in the wild depended on their ability to immediately flee from predators. In a threatening situation, the autonomic nervous system (ANS) instantly activates the sympathetic branch (responsible for the "fight or flight" response).

A massive dose of adrenaline and cortisol is released into the bloodstream. Blood is immediately redirected away from the digestive tract and into organs crucial for survival: the heart, lungs, and skeletal muscles, which tense up like guitar strings, ready for an immediate burst of speed.

The problem arises when stress becomes chronic. A prolonged elevation of cortisol levels permanently raises baseline muscle tone, alters body posture, and ruins the horse's motor coordination. Furthermore, chronic stress can lead to so-called "adrenal fatigue" (hypocortisolemia), where cortisol levels drop drastically. When this happens, the horse becomes chronically exhausted, apathetic, stiff, and completely loses the desire to cooperate.

Stress, Ulcers, and Back Pain: The Vicious Cycle

Chronic stress causes the blood vessels in the abdominal cavity to constrict. The result? The gastric mucosa loses its protective properties, and hydrochloric acid begins to erode it, leading to painful ulcers (this issue affects up to 90% of performance and stalled horses!). A horse experiencing stomach pain reflexively tenses its back muscles to protect the painful area. A vicious cycle is born: stress generates ulcers, ulcers generate pain, pain tenses the back, and a tense back magnifies the stress.

2. Movement vs. Stress: Comparing the Effects on Tissues

Can movement be harmful? Of course, but only when it is incorrect or combined with stress. Under normal conditions, movement is a natural medicine for the horse.

The Muscle as a Sponge: A correctly functioning muscle behaves like a sponge, during contraction, it squeezes out blood and metabolites, and during the relaxation phase, it draws in fresh, oxygenated blood rich in nutrients. However, a prerequisite for this is complete relaxation, which only occurs when the horse is psychologically relaxed. In equitation, this willingness for unforced, elastic movement is called throughness (przepuszczalność).

When Does Movement Generate Pain? True, pathological tension after exertion (such as exertional rhabdomyolysis, or "tying-up") most often appears when a sudden workload is placed on an unprepared body, combined with a lack of warm-up, dietary errors (excess sugars), and... emotional stress, such as transport or competition pressure.

3. What Stresses Our Horses Most? (We Often Forget This!)

The triggers of stress in horses are rarely spectacular. Most often, they are minor, everyday environmental factors that we completely ignore:

1. Stall Conflicts: A horse kept next to a neighbor it genuinely dislikes never fully rests. Permanent tension accompanies the horse 24 hours a day.
2. The Weather (Especially Wind): The worst weather factor that triggers anxiety in horses is gusty wind, which makes it difficult for them to monitor their surroundings. If you add heavy rain or snow to this, along with a lack of shelter (such as a run-in shed in the paddock), the horse will intensely tense its muscles just to maintain its body temperature.
3. Rider Tension: Horses absorb our emotions and tension like a sponge. If you mount your horse after a hard day at work with a clenched jaw and tight hips, your horse will mirror it instantly.
4. Poor Nutrition: A diet deficient in minerals, especially a lack of magnesium, drastically lowers the horse's threshold for stress responses, causing constant anxiety and painful muscle cramps. Conversely, an excess of simple sugars and starch from grain leads to hyperactivity.

4. Trigger Points: Why Is the Horse Lame When the Joints Are Healthy?

Traditional veterinary diagnostics focus primarily on bones, joints, and tendons. Often, however, a horse shows movement asymmetry or a shortened stride, yet X-rays or ultrasounds reveal zero changes. The culprit might be myofascial trigger points (MTrPs).

These are extremely painful, microscopic nodules located within taut bands of muscle fibers, forming under the influence of chronic stress and overload, among other things. Worst of all, these points have the ability to generate what is known as referred pain. For example, a trigger point located in the hindquarter muscles (such as the gluteal muscle) can project pain down the limb, mimicking a hoof or hock condition. Classic diagnostic nerve blocks will not isolate the source of the problem, leading to misdiagnoses and ineffective treatments. A direct link has also been demonstrated between the presence of trigger points in the pectoral muscles and defensive reactions or resistance during girthing (girth-aversion).

5. How to Help a Tense Horse: A Practical Guide

Releasing a horse from tension requires a holistic approach. Here is what you can do starting today:

Movement as Therapy and Self-Regulation

Do not lock your horse in a stall "so it can rest." For a horse, true relaxation is free movement in a paddock with friends. Interestingly, stereotypies such as weaving or cribbing are not "vicious habits", they are attempts at self-regulation by an overloaded nervous system. Through rhythmic movement, the horse stimulates the release of endorphins, which bring relief from stress.

Working in a Low Head and Neck Carriage

Correct gymnastics in a low and stable neck carriage (for example, at the walk at the beginning of a ride) stretches the nuchal ligament, lifts the back, and activates the abdominal muscles. This is an excellent relaxing exercise, but remember moderation, forcing this position excessively or for too long can overload the cervical vertebral joints.

Activating the Parasympathetic Nervous System (Rest and Regeneration)

Physiotherapy and osteopathy can work wonders in calming the horse's nervous system. Gentle craniosacral therapy (CST) and work on the ribs and diaphragm (known as rib raising) stimulate the vagus nerve, switching the body from a state of fight-or-flight into a state of deep relaxation.

How can you tell that a horse is letting go of tension during a session? Observe its autonomic reactions:

• Yawning (occurs in about 34.4% of horses)
• Lowering the head (in nearly 78.1% of horses)
• Dropping ears to the sides (in over 62.5% of horses)
• Licking, chewing, and active blinking

Audible gut sounds (gurgling stomach) – this is a sign that the digestive tract is returning to work as the stress quietens down (parasympathetic dominance).

Scientific Bibliography

1. Bowen, A. G., Goff, L. M., & McGowan, C. M. (2017).Investigation of Myofascial Trigger Points in Equine Pectoral Muscles and Girth-Aversion Behavior. Journal of Equine Veterinary Science, 48, 154-160. , ,
2. ``Klinck, M. P., et al. (2024).Behavioral Assessment of Equine Relaxation Following Manual Therapy: A Pilot Study. PMC12474095.,
3. Marlin, D., et al. (2025).From Biomechanics to Welfare: Integrative Advances in Equine Sports Medicine and Rehabilitation. PMC12466741. [21], ``, [21]
4. McLean, A. N., & McGreevy, P. D. (2022).Muscular activity, behavioral, cortisol and hematocrit responses to acute stressors in horses. PMC8935158. ``
5. Gunnarsson, V., et al. (2026).Myofascial trigger points as a primary cause of equine lameness: a biomechanical, neurophysiological, and fascial review. Frontiers in Veterinary Science. [16], [17], [17]
6. Schulz, K., et al. (2025).A structured exercise regimen enhances autonomic function compared to unstructured physical activities in geriatric horses. Scientific Reports. ``
7. Yonezawa, T., et al. (2024).Changes in stress response via heart rate variability (HRV) in horses participating in jumping events on consecutive days. Frontiers in Veterinary Science. ``
8. Covalesky, M., et al. (2019).Reactivity and emotional responses of horses involved in different equine activities: behavioral and physiological responses. MDPI Animals. ``