Did you know that you have between 500 and 600 constantly active muscles in your body? They account for around 40% of your weight and are supported by others that are inconstant. In this post, we want to help you to get to know the body a little better, and more specifically, explain what muscle receptors are and what their role is. This is a key question to attune yourself to your body and get the most out of your workouts.
What types of muscles are there?
Depending on the type of muscle tissue they are made of, we can divide muscles into three categories, each with a differentiated structure and functionality:
- Skeletal. This muscle is responsible for moving bones and other structures. They contract and relax based on messages consciously given by the nervous system. This tissue is made up of so-called muscle fibers, created by elongated cells with a striated appearance.
- Cardiac. This muscle’s function is to contract the heart so that it can pump blood and keep the body alive. It is located in the middle layer of the heart, called the myocardium, which contracts from signals received from the heart conduction system. Thanks to their existence, your heart beats.
- Smooth. This muscle is located in the walls of hollow organs: the eye, blood vessels, the respiratory tract, the stomach’s digestive tract, the uterus and the bladder. In order to make various bodily functions possible, it changes shape. This muscle’s movements are not conscious, but without them, we wouldn’t exist.
In our body, we have muscles whose activity is under our conscious control. They are put into action, for example, when you decide to walk, swim, throw a ball or type on a keyboard.
They perform their role unconsciously. We don’t have to decide to activate them, because they are always acting as they’re meant to, independently of our will.
Therefore they are switched on without the mediation of the human brain. There is an example that reflects this reality very clearly: why is it that when you put your head under water and try to hold your breath as long as possible without wanting to come up, you end up springing back up anyway? Because the involuntary muscles react in a contrary way to that decision. Breathing, heartbeat and bowel movements are included in this type of human muscle.
Types of muscle fibers
Muscle fibers are another fundamental element for the functioning of our body. What are they? The cells that make up muscle tissue. Their grouping together forms contractile units capable of causing the required movement. There are three types: slow or red (type I), intermediate (type IIA) and fast or white (type IIB). All your muscles include them, to a greater or lesser extent, depending on their usefulness.
Genetics is also an aspect that influences their composition, although training and adaptation to exercise can change that reality. In the latter case, what happens is not that some fibers are transformed into others, but that they become adapted to certain exercises through practice.
Below, we will tell you in more detail what are the main characteristics of each of the muscle fibers.
- Fast fibers. White or type IIB fibers spring into action as soon as we do anaerobic exercise. They respond, therefore, to high intensity and short duration activity. They stand out for their ability to generate a lot of energy in a short time, as well as a lot of strength. They have less vascularization, as they do not need as much oxygen as the others. On the other hand, they tire out more quickly.
- Slow fibers. Red or type I fibers respond to aerobic activation: long duration and medium intensity. They use oxygen and other nutrients as a source of energy, so their vascularization is the greatest. They contract slowly, with less force and do not tire out as quickly. They are very red, given the amount of blood capillaries and myoglobin.
- Intermediate fibers. The qualities of type IIA fibers are somewhere in between the two previous ones. As a result, they contract quickly and are moderately resistant to fatigue. They have a medium diameter and also have a reddish hue.
At all times, whether you are standing or exercising, muscle receptors are responsible for capturing and transmitting valuable information to your body. Specifically, they share information on your joints, your muscles, distance and temperature, to name a few.
They are located in the muscles and tendons and are focused on two aspects: tension and length. The data they transmit is essential in both fields.
Next, we’ll take a closer look at the two most important receptors in contractile activity.
They are considered to be the most important proprioceptive sensory organs. They are located in the extrafusal fibers and are spindle-shaped. Their job is to regulate the excitability of sensory nerve fibers. As a result, we are able to stretch the muscles appropriately in every active situation.
When we are at rest, we can also know, thanks to them, the reflex and static position of our muscles.
Golgi tendon organs
These receptors are located in the joint between the tendon and the muscle, and have a type lb sensory nerve. They are capable of generating a discharge from mechanical deformation. In other words, as a result of muscle contraction or stretching.
How is it possible for a muscle to activate and contract? In theory, it is much easier to understand it than put it into practice, because in any human body, this process occurs almost instantaneously. And what’s more, it takes place in many muscles at the same time. Isn’t the human body amazing?
The role of the nervous system
The main agent of this response is our nervous system. It works like the electrics in a house, only with infinitely greater precision. The cells that form it, the neurons, are in charge of transmitting each nerve impulse from one to another until it reaches the correct muscle.
To explain this process in detail is complex because of the many technical names involved. Let’s just say that the neurons are linked directly to the muscle, through what is known as the neuromuscular joint. Ultimately, the motor neuron communicates directly with the muscle fiber and completes the process.
On its longest branch, each neuron has a transmitter called an axon, equipped with flat disc-shaped terminals. These terminals are known as motor endplates and are responsible for linking each fiber to its neuron.
The nerve impulse is generated when the axon terminals release the precise neurotransmitters.
Acetylcholine and noradrenaline are the most important neurotransmitters. The exchange of both substances is what really determines the success of the nerve impulse. Subsequently, the muscle will contract correctly depending on the number of fibers that have been stimulated and their speed.
Fundamentally, the effects generated are of two types:
- Summation of several muscle fibers. Spatial summation starts with the smaller motor units and works its way up to the larger ones. In this way, the desired adjustment of muscle strength is achieved.
- Temporal summation These are individual contractions that are carried out faster and faster. So much so that when the next one starts, the previous one hasn’t even finished yet. The strength of the muscle is thus increased and can generate the tetanization, or in other words, a continuous contraction caused by many successive individual contractions.
How can we stimulate muscles?
Those of us who practice sport are often very interested in identifying how to stimulate our muscles. Does this sound familiar?
When it comes to training, there are many practical tips for stimulating your muscles earlier and in greater quantities. These include the following:
- Perform each exercise slowly.
- Push your pain threshold during your workout.
- Be consistent when training: train three to five times a week.
- Eat plenty of protein.
- Start your workout with muscle-focused activities.
- Alternate your routines on a regular basis: approximately every 30 to 40 days.
- Perform each exercise at 65% of the maximum load.
- Once you have achieved your goal, keep training.
“Electrostimulation, an ideal resource to complete traditional training and get the most out of your effort and body.”
On the other hand, there’s some very advanced technology that is proving to be very effective in this area. Muscle electrostimulation works, and it does so very well, when applied correctly. It is an superb ally if you are looking to achieve an excellent physical shape or, simply, lose weight with electro-stimulation. An ideal resource to complement traditional training and get the most out of your effort and body.
The electrostimulation will accelerate your muscular hypertrophy, as long as you accompany it with specific training. It will help you to increase the size of muscle fibers in order to increase their total volume, faster and better. Putting yourself in the hands of specialized professionals, who have the right technology and knowledge, is the key to the success of electrostimulation and well-worked muscles.
Now that you know how your muscle fibers and receptors work, you’re in a position to train better and make the right sporting decisions. Are you ready? Don’t forget to subscribe to our blog for more tips and advice!