What is Massage? Part 4c: Muscle Tissue

The main tissue associated with, and manipulated by, massage is MUSCLE. The gorgeous, elastic power-houses that produce movement and make horses the athletes they are. Hold on tight because this is going to be a very detailed post about this amazing tissue.

There are three types of muscle tissue:  

 

Smooth

Cardiac

Smooth tissue supports the epithelial tissue surrounding blood vessels and hollow organs. Cardiac tissue is a very specific tissue that makes up most of the heart’s bulk. Both of these tissues are involuntary, meaning they are not easily influenced by anything other than hormonal or chemical changes.

Skeletal

Skeletal tissue is the only voluntary type of muscle tissue and the most easily manipulated. It is influenced mainly by the nervous system and the skeletal muscles come in a variety of shapes and sizes. As discussed in the last post, a muscle has two tendons: and origin and an insertion. Between those tendons is what is called the belly.

(Hourdebaight, 27)

The belly is where the action of the muscle happens. It is made up of bundle of fibers. Nerve impulses cause the muscle fibers to react and fold over themselves causing the belly to contract which moves the skeleton.

These fibers are classified by color and contraction speed. Fast-twitch white, fast-twitch red, and slow-twitch red.

Fast-twitch white is low in myoglobin, a red protein that carries and stores oxygen, and most easily fatigued. Muscles with a higher ratio of white fibers are best suited to sprinting or sports that have sudden, short bursts of speed and anaerobic activity.

t3athlete.com/blog/2016/8/15/training-for-speed-developing-fast-twitch-muscle-fibers

Slow-twitch red is high in myoglobin and not easily fatigued. Muscles with a higher ratio of red fibers are best suited to endurance racing or sports with long, aerobic activity.

Horses also have fast-twitch red fibers which land between fast-white and slow-red in terms of resistance to fatigue. In humans, these fibers are very rare.

Genetics determine the ratio of white to red fibers and, therefore, what job a horse is best suited for. Quarter Horses have a higher white to red ratio and so are best for cutting, roping, and reining jobs which require them to chase after sporadically moving cattle. Arabians have a higher red to white ratio and are best suited for long slower travel over many miles.

Contraction happens when a muscle is stimulated by the nervous system. There are three types of contraction: concentric, eccentric, and isometric.

Concentric and eccentric contraction are what we recognize as movement. Concentric pulls a bone to move it, eccentric acts against concentric to stabilize the bone’s movement. So, while one muscle concentrically contracts, the opposing muscle slowly releases in eccentric contraction. Usually the muscles are situated on opposite sides of the bone or joint they are acting upon. The gif below shows both.

Isometric contraction occurs when the muscle contracts but no movement is seen, like when pushing against an immovable object. There is no shortening or elongation of the muscle during this type of contraction. You can see this happening when a horse is riding in a trailer attempting to keep its balance or when trying to pull a heavy load like in draft horse pulling competitions.

Muscles contract in groups with many muscles acting on one bone or joint. The muscle performing concentric contraction during movement is called the agonist, the muscle performing eccentric contraction is called the antagonist. Synergists are muscles that assist the main agonists and antagonists of a given group.

Muscles are divided by either their proximity to the skeleton, or the joints they affect.

There are the superficial muscles:

(Hourdebaight, 28)

These muscles are the outer most layer of muscles, the furthest from the skeleton. They are easily seen when a horse is moving. You can also see some of the planes of fascia in the image on the far left, pictured as the white areas.

  

These are the deep muscles:

(Hourdebaight, 36)

 These muscles are between the superficial and the extremely deep muscles that hold the spine together. Most of these are the largest in the body and hold the most power. They are harder to affect, but not impossibly so.

And congratulations. You have made it through some very difficult and complex information. It can be overwhelming if you try to absorb it all at once, so I suggest you read the posts multiple times and refer back to them with future posts. The next post will be on different massage techniques.