Myotatic Reflex: Involved Anatomy, How It Is Produced and Avoided

What is the Myotatic Reflex?

The nervous system of mammals is very complex. For most of the major actions in the body, the brain must decide what movement or action should be taken, the nerve impulses must be transmitted outside the brain, down the spinal cord and towards the desired recipient.

Then, when the action is carried out, the impulse must go back through the reverse path to tell the brain that it was completed and begin the next process.

This is the way for any conscious and controlled impulse by the brain. Although many words are needed to explain, it is really a very fast process.

There are many processes in the body that do not require direct reflection to complete. The functions of the heart, respiration, metabolic processes, the fight against diseases and many other autonomous processes occur automatically in the body.

The body uses signals to increase, decrease or maintain many of these actions. If the levels of carbon dioxide in the body begin to increase, the autonomic nervous system, through acid-base thermostats, requires an increase in the respiratory rate.

The reflex and the nervous system

Another automatic response of the nervous system is reflex. The body reacts by default depending on a specific stimulus. This can be a practiced response or a preprogrammed one. The miotic reflex is one of those answers.

The myotatic reflex or deep tendon reflexes, is a response preprogrammed by the body to a stretching stimulus in the muscle.

When a muscle is stretched, an impulse is immediately sent to the spinal cord and a response is received to contract the muscle. Since the impulse only has to go to the spinal cord and return, not all the way to the brain, it is a very fast impulse (usually it happens in 1-2 milliseconds).

This is designed as a protective measure for the muscles, to prevent tearing. The muscle axis is stretched and the impulse is also received immediately to contract the muscle, protecting it from being pulled forcefully or beyond a normal range.

The synergistic muscles, those that produce the same movement, are also innervated when the stretch reflex is activated. This further strengthens the contraction and prevents injuries.

At the same time, the myotatic reflex has an inhibitory aspect for the antagonist muscles.

When the stretch reflex is activated, the impulse is sent from the stretched muscle spindle and the motor neuron is divided so that the contract signal can be sent to the stretched muscle, while a signal can be sent to relax the antagonist muscles.

Without this inhibitory action, as soon as the stretched muscle began to contract, the antagonist muscle would stretch causing a stretch reflex. Both muscles would end up contracting simultaneously.

The myotatic reflex is very important in posture. It helps to maintain the correct posture because a slight inclination towards either side causes a stretch in the muscles of the spine, the hip and the leg towards the other side, which is quickly counteracted by the stretch reflex.

This is a constant process of adjustment and maintenance. The body is constantly under pushing and pulling forces from the outside, one of which is the force of gravity.

Another example of the myotatic reflex is the knee test performed by doctors. When the patellar tendon is hit with a small hammer or other device, it causes a slight stretch in the tendon and, consequently, the quadriceps muscles.

The result is a rapid, albeit slight, contraction of the quadriceps muscles, which results in a small kicking motion.

Anatomy involved

The muscles are attached to the tendons, which hold them together to the bone. The muscles have tendons in each accessory. In the union of the muscle to the tendon there is a muscular spindle that is very sensitive to stretching.

The motor neurons that activate the muscles join here as well. These are considered inferior motor neurons. When stimulated they can cause the muscle to contract.

This releases the upper motor neurons and other parts of the central nervous system for more important functions.

Motor neurons travel from the spinal cord to the muscle and back in a continuous cycle. Conscious movement comes from impulses in the brain that travel through the spinal cord, over this circuit, and then back to the brain for processing.

The myotatic reflex skips the part of the brain from the trip and follows the simple loop of the muscle to the spinal cord and back, making it a very fast sequence.

What causes it?

The myotatic reflex is caused by a stretching in the muscular spindle. When the stretch impulse is received, a rapid sequence of events occurs. The motor neuron is activated and the stretched muscles and their support muscles contract while the antagonist muscles are inhibited.

It can be activated by external forces (like a load placed on the muscle) or internal forces (motor neurons are stimulated from within).

An example of the first is a person holding an empty tray on his outstretched arm and then having a plate of food on his arm himself. The stretch reflex would activate to keep the tray at the same height and balance.

Any sudden and forceful stretching in the muscle causes the myotactic reflex to trigger, in a healthy person. Delays in the absence of the myotatic reflex are signs of possible neurological or neuromuscular involvement.

What should be avoided when stretching?

Many people never learned to stretch correctly. Maybe you’ve done this yourself: you see other people stretching in the gym and trying to imitate what you see.

But who can say that the person you are looking at is doing things right? These are some of the most common mistakes made when stretching:

Rebound; Many people have the wrong impression that they should bounce to get a good stretch. Bouncing will not help you and could do more damage as you try to go beyond the stretch reflex.

Every movement you make must be gentle and gentle. Gradually lean towards the stretch, push to the point of slight tension and hold it like that for a few seconds. Each time you can go a little further, but do not force it.

Do not keep the stretch long enough. If you do not hold the stretch long enough, you may fall into the habit of bouncing or rushing during your stretching training.

Hold your stretch position for at least 15 to 20 seconds before returning to its original position.
You should also avoid stretching too hard. Stretching requires patience and delicacy. Do not throw your body to a stretch or try to speed up your stretching routine. Take your time and relax.