Targeted Muscle Building in Horses

Building Muscle in Horses – How Training and Feeding Work Together Effectively

As soon as the days grow longer in the spring and nature comes back to life, many riders and horse owners feel motivated to jump right back into training after the winter break—or even to compete. The anticipation of finally being able to resume training after a prolonged illness-related hiatus is just as great. But caution is advised here: After a long break, the horse needs time to gradually rebuild both its muscle mass and its endurance.

Effective muscle building depends on several interrelated factors. Regular exercise, a well-designed training plan, and a diet tailored to the horse’s needs form the foundation. Supplements alone are of little use if the horse spends most of its time in the paddock. Similarly, even the best-structured training plan will not produce the desired results if the horse’s diet is not adjusted accordingly.

The horse’s muscular system – structure and energy production

The muscular system is the foundation of all movement and is therefore essential for riding. Within the muscle cells, the energy absorbed from feed is converted into mechanical work, enabling the body to move at all.

Two distinct types of fibers can be identified in the horse’s skeletal muscles: red and white muscle fibers, each specialized for different performance demands. Red muscle fibers contain a high amount of myoglobin, a pigment that transports oxygen into the cells. This enables them to generate energy from fat reserves using oxygen. They work relatively slowly but are characterized by high endurance and can remain active for extended periods. This fiber type is particularly well-developed in endurance horses, such as those used in endurance racing.

White muscle fibers, on the other hand, are responsible for fast and powerful movements. They contract very rapidly and generate great force, but they tire much more quickly. They derive their energy without oxygen from readily available reserves such as adenosine triphosphate (ATP) or stored glycogen. Because they contain very little myoglobin, they appear much lighter in color and give this fiber type its characteristic hue. The proportion of these fast-twitch fibers is particularly high in racehorses.

How feeding supports muscle development in horses

Muscles make up a significant portion of a horse’s body, accounting for about 45% of its total body weight. Since muscle tissue is largely composed of protein, the supply of protein through feed plays a central role—both in building and maintaining muscle mass. It is not only the quantity that matters, but above all the composition of the protein.

Proteins are composed of various amino acids. The body can produce some of these on its own, while others must be obtained through the diet. These so-called essential amino acids are particularly important for muscle development. Feedstuffs such as oats provide a favorable amino acid profile and are therefore well-suited for performance-oriented horses.

The most important building blocks include, above all, lysine, methionine, and threonine. These are considered limiting because they play a key role in muscle development: if even one of these amino acids is missing, the body cannot form sufficient protein structures. A deficiency - such as in lysine - can therefore significantly slow down or even prevent muscle growth. To ensure a targeted supply, the use of a dietary supplement like EQUIPUR-amino can be beneficial, as it provides precisely these important amino acids in a balanced formulation.

Amino acids and muscle building – how the two interact

The processes involved in energy production within muscle cells can be influenced to a certain extent through diet. First, the body draws on adenosine triphosphate (ATP), which, however, is available only in very limited quantities and is quickly depleted. Afterward, the body utilizes stored energy reserves, primarily glycogen, which is stored in muscles and the liver as a form of glucose. The size of these reserves depends on both fitness level and the amount of carbohydrates consumed.

As soon as these carbohydrate stores run low – usually after about an hour of exertion – the body increasingly switches to using fat reserves. While the short-term energy available in the form of ATP can hardly be influenced by diet, the long-term energy stores can be specifically controlled through nutrition. By providing carbohydrates – such as through grains and hay – as well as fats, the energy supply to the muscles can be sustainably supported.

How muscle mass develops in horses

When building muscle mass, no new muscle cells are created. Instead, the body responds to training stimuli by storing more protein in existing muscle fibers. This makes them thicker and more powerful. High-quality dietary supplements can support this process by providing the necessary building blocks for muscle protein synthesis.

Spring training – laying the groundwork for the upcoming tournament season

With the upcoming season in mind, the primary focus is on improving physical performance. Training aims to adapt the cardiovascular system to increasing demands. Additional blood vessels develop in the muscles, making oxygen delivery more efficient. At the same time, the number of red blood cells and the hemoglobin content in the blood increase. The result: The heart works more efficiently and can supply the muscles with sufficient oxygen with less effort.

Conditioning training for horses – getting back into shape step by step

After extended breaks, such as during the winter or following an injury, horses often lose muscle tone and stamina. If the horse has been exercised at least lightly during this time, getting back into training is usually a bit easier, as a certain level of basic fitness is maintained. Especially in the beginning, it is crucial to combine exercise and rest in a sensible way. Training stimuli trigger adaptation processes in the body that can manifest, among other things, as sensitive muscles – similar to muscle soreness. Depending on the horse, this may be more or less noticeable.

On days without intensive training, exercise should still take place, for example in the form of light lunging or relaxed walks. This active recovery helps the body adapt to the new demands. This principle is known as supercompensation: a phase of exertion is initially followed by fatigue, then regeneration – and finally a slightly increased level of performance.

It is essential to avoid building up your training too quickly. Overdoing it can lead to increased lactate buildup in the muscles, which promotes acidification and consequently a drop in performance. In addition, microscopic damage can occur in the muscle fibers, causing pain. It is equally important to remember that tendons and ligaments adapt much more slowly than muscles. Therefore, it makes sense to plan your training progression with a bit more flexibility to avoid overloading the musculoskeletal system.

To track progress, it can be helpful to document your starting point with photos – especially of less muscular areas. This allows you to clearly document changes as training progresses. It is easier to observe muscle development during groundwork, specific exercises, or lunging than while riding.

Muscle building in horses following illness or prolonged lameness

Horses suffering from conditions such as laminitis, equine Cushing’s syndrome, or equine metabolic syndrome are often fed a very restricted diet and are frequently given only coarse, older hay. While this type of diet is usually sufficient in terms of energy intake, it often lacks essential amino acids. This makes effective muscle building significantly more difficult - in some cases, the situation can even develop in the opposite direction.

When the body lacks important protein building blocks for repair and metabolic processes, it draws on its own reserves. Among other things, muscle tissue is broken down to meet these needs, leading to a visible loss of muscle mass.

To avoid this, it makes sense to specifically supplement a low-calorie diet with high-quality amino acids. This helps support both the maintenance of existing muscle mass and gradual muscle recovery, while also stabilizing overall metabolism.

Suitable supplements, such as EQUIPUR-amino, can be helpful here, as they specifically provide the most important amino acid building blocks.

Nutrition to support muscle mass in older horses

As horses age, their ability to efficiently utilize nutrients from their feed declines. This particularly affects protein utilization, while deficiencies in minerals and vital nutrients often develop as well. Furthermore, many older horses can no longer be exercised regularly due to health issues, resulting in a growing lack of the physical stimulation that is essential for muscle health.

To counteract the loss of muscle mass, daily feed should be specifically supplemented with essential amino acids. These are easily absorbed and can be used directly by the body for metabolic processes as well as to maintain existing muscle mass.

A feed supplement specifically formulated for older horses, such as EQUIPUR - senior, takes these changing needs into account and helps ensure that their nutritional requirements are met during this stage of life.

Muscle development in older horses usually proceeds much more slowly than in younger animals. For this reason, a well-thought-out, gradually built-up, and long-term training plan is particularly important for providing optimal support to the body. In addition, a targeted supply of essential amino acids – for example, through products like EQUIPUR - amino – can be beneficial to further promote muscular adaptation processes.

Beware of tying-up

A common exercise-induced muscle disorder in horses is known as tying-up. This risk should not be underestimated, especially when building up a training regimen. Acute tying-up typically occurs when a horse is worked again after a period of rest—particularly if the amount of concentrated feed, and thus the intake of carbohydrates, has not been adjusted on days off from training.

The carbohydrates consumed are converted into glycogen in the body and stored in the muscles. If the horse is then subjected to exercise, this glycogen is broken down very quickly. However, if the amount is too large, the metabolism can no longer regulate these processes adequately. This results in the production of metabolic byproducts such as lactate (lactic acid), which can accumulate in the muscles and damage the tissue.

To be able to react early, it is helpful to be familiar with the different types:

Mild form (first signs shortly after work): The horse appears tense or restless, moves stiffly—especially in the hindquarters—and often has an arched back.

Moderate form (symptoms already present during exercise): The horse slows down, moves noticeably stiffer, the muscles in the croup area are hardened, and the lower back is sensitive to touch.

Severe form / classic tying-up (often occurs within a short time even with minimal exertion): The horse shows obvious signs of pain, appears anxious, has difficulty moving its hindquarters, may develop colic-like symptoms, and passes dark-colored urine.

An appropriate diet, regular exercise, and a carefully structured training regimen play a crucial role in significantly reducing the risk of painful muscle problems such as lumbago.

A quick overview – effective muscle building in horses

• Start slowly: After breaks, gradually rebuild muscle mass and stamina—don’t overdo it.
• Training and nutrition go hand in hand: Only the combination of exercise, a training plan, and proper nutrition leads to success.
• Understanding muscle fibers:
  • Red fibers = endurance-oriented, work with oxygen
  • White fibers = fast & powerful, but tire more quickly
• Protein is crucial: Muscle tissue consists mainly of protein – quality and composition are more important than sheer quantity.
• Essential amino acids: Lysine, methionine, and threonine are particularly limiting and must be obtained through the diet.
• Energy supply:
  • Short-term: ATP (quickly depleted)
  • Medium term: Glycogen (depending on training & diet)
  • Long term: Fat reserves
• Muscle growth: Keine neuen Zellen – vorhandene Muskelfasern werden durch Training dicker und leistungsfähiger.
• Richtiger Trainingsaufbau: Wechsel aus Belastung und Erholung (Superkompensation) ist entscheidend.
• Überforderung vermeiden: Zu intensives Training kann zu Übersäuerung (Laktat), Leistungsabfall und Muskelschäden führen.
• Sehnen & Bänder beachten: Passen sich langsamer an als Muskeln – daher genügend Zeit einplanen.
• Nach Krankheit/Lahmheit: Häufig Aminosäuremangel → gezielte Ergänzung unterstützt Muskelaufbau und -erhalt.
• Seniorpferde: Verminderte Nährstoffverwertung → leicht verfügbare Aminosäuren und ein angepasstes Training sind besonders wichtig.
• Kreuzverschlag-Risiko: Besonders nach Ruhephasen bei hoher Kraftfuttergabe → Fütterung und Training anpassen.
• Vorbeugung: Bedarfsgerechte Ernährung, regelmäßige Bewegung und ein durchdachtes Training schützen vor Muskelproblemen