Koper Equine

The very conformation adaptations that make a horse so fast and athletic also make it necessary that he’s fully prepared to face the athletic demands placed upon him.

Horses have no muscles below their knee and hock joints—only a complex combination of bones, tendons, and ligaments support the entire weight of a horse in full stride. Unlike muscles, which are stretchy, especially once warmed up, tendons and ligaments are not. This evolutionary design allows the massive muscles up high to leverage the kinetic tensile strength of sinew down low, converting it into raw speed with minimal effort.

But what happens when the muscles can no longer produce the effort required to keep a horse moving, despite its continued effort?

The F word: FATIGUE

With fatigue, the forearm muscles—the flexor muscles holding up the fetlock—relax, causing the tendons and ligaments to absorb more mechanical stress. The fetlock droops towards the ground, delaying the breakover of the foot. This is even worse if the foot has a long toe and low heel, common in many racehorses. This puts unnatural strain on the tendons as the hoof tries to roll over the toe at the end of the stance phase of the stride. At best, this can cause tendon strain; at worst, the consequences can be catastrophic.

Fatigue comes in four varieties: (1) lactic acid buildup; (2) fuel depletion; (3) structural fatigue; and (4) metabolic fatigue. Any of these can initiate a cascade of failure that could lead to a career-ending injury or worse. Delaying fatigue so it doesn’t occur during training or competition makes horses exponentially safer.

Each form of fatigue has its own causes and remedies:

Lactic Acid Fatigue occurs when fast-twitch muscle cells rapidly burn glycogen anaerobically, without oxygen. This process generates lactic acid as a byproduct, which accumulates in and around the muscle cells. The presence of lactic acid lowers the pH level within the muscles, contributing to muscle fatigue and reduced performance during intense exercise.

Combatting lactic acid fatigue requires thorough training. A horse’s body will adapt to withstand stresses if they are introduced gradually. Sustained workloads producing medium to high lactic acid levels lead to changes within muscle cells that delay the buildup of lactic acid to fatiguing levels.

Fuel Depletion Fatigue: Fast-twitch muscle cells, which do much of the work in a fast-moving horse, rely on glycogen stored in the bloodstream and within the muscle cells. The brain also relies on glycogen. When glycogen stores dwindle during a race or strenuous workout, the body prevents complete depletion by shutting off muscle cells’ ability to burn glycogen. Without fuel, muscle cells can’t fire, and the horse slows down.

Preventing fuel depletion fatigue is straightforward: ensure muscle cells are filled with fuel. Proper training, rest and appropriate feeding for the horse’s workload lead to increased muscle mass, or fuel storage.

Structural and Metabolic Fatigue: These types of fatigue are related and share a common remedy. Structural fatigue can be compared to bending a paperclip back and forth until it breaks. Any repetitive motion performed beyond the body’s rebuilding capabilities causes structural breakdown. Similarly, metabolic fatigue results from overtaxing races or workouts followed by insufficient rest and recovery.

The cure for both structural and metabolic fatigue is patience, rest and preparation Avoid progressing too quickly to heavier workloads and allow plenty of time between taxing efforts. This enables the horse’s body to respond favorably to increasing demands, becoming stronger with each stage of training.

Effective management of your sport horse involves gradual training, ensuring adequate fuel supply, rest, and preparation to mitigate structural and metabolic fatigue. This approach optimizes performance and preserves equine health and longevity.