How Much do You Know About Equine Muscular System?


Author By Hope Horse

It is well known that muscles are elastic tissues, and all movements of animals are accomplished through ligaments connecting the bones and joints, 

facilitated by the stretching and contracting of muscles, while tendons act to store and release energy, reducing the workload of muscles.


Muscles are composed of different fibers, and horses primarily have two types of muscle fibers: fast-twitch fibers and slow-twitch fibers. 

As the names suggest, fast-twitch fibers can generate energy instantly, allowing horses to accelerate and sprint, but they quickly fatigue. 

On the other hand, slow-twitch muscle fibers are more inclined to endurance sports, reducing explosive power and increasing endurance, 

allowing them to work for long periods of time. The proportion of fast-twitch and slow-twitch fibers varies among different types of horses.

Horse muscles are roughly divided into five types: skeletal muscle, cardiac muscle, smooth muscle, deep muscle, and superficial muscle.


1. Skeletal muscles: Attached to bones, these muscles are the main driving force of the movement system. 

These muscles are controlled by their own consciousness and can complete various movements. 

There are 700 different skeletal muscles in the horse, responsible for supporting and protecting the bones and internal organs, enabling voluntary movements. 

They are the active muscle.


2. Cardiac Muscle: The cardiac muscle of horse contracts around a hundred thousand times a day on average, 

exhibiting high endurance and strength, characterized by striations.


3. Smooth Muscle: Smooth muscles are not under conscious control and are distributed throughout the horse's body such as arteries and veins, digestive and respiratory systems. 

Their function is to breathe, transport blood, delivery food and more. 

They are the passive muscles of the body, controlled by the autonomic nervous system


4. Deep muscles: The main function of deep muscles is to maintain body stability and posture. 

They are attached to the bones with multiple starting points and ending points, responsible for supporting individual joints of the body. 

For example, the deep muscles of the horse's forelegs stabilize the forelegs to the trunk, as they need to support the horse's head and neck, 

which accounts for two-thirds of the horse's weight. Below the knee of the forelegs, there are mostly tendons and ligaments.


5. Superficial muscles: Superficial muscles are located between the skin and deep muscles and also contribute to movement. 

They vary in thickness, with some being robust like the gluteal muscles and others being thinner like the oblique muscles.


Horses lack muscles in their lower legs to reduce weight, thus enabling more efficient energy usage. 

Conversely, there are large muscle masses on their hind legs, providing power for forward propulsion.


Another very interesting point is that the reason why horses sleep standing up is because each leg has a system called a "supporter", 

composed of ligaments and tendons, which can lock the main joints.

This not only reduces the energy consumed by standing, but also allows the muscles to rest.