The 4 types of muscle contraction, with examples

A classification of the types of muscular contraction, useful for knowing how to exercise well.

How do muscles work? How many muscles would you say we have in the human body?

In this article, in addition to answering these and other questions, you will see explained what is a Muscle contraction, and what are the different types of muscle contraction that exist.. Here you will also find examples of each one, through simple exercises or everyday acts of daily life.

Muscles and how they work when exercising

Before talking about the different types of muscle contraction that exist, it is necessary to know, broadly speaking, what a muscle is and what a muscle contraction consists of.

As we well know, people and animals have muscles all over our bodies, which cover our skeleton. Specifically, human beings have about 650 muscles distributed throughout the body, of different sizes.of different sizes. All of them are voluntary muscles, that is, we can move them at will (unless we have a pathology or disease that prevents us from doing so).

Muscles are a type of organ formed by a tissue of fibers that contract a fabric of fibers that contracts and relaxesdepending on the type of movements we make. In other words, muscles allow movement.

For its part, a muscular contraction is a physiological process in which muscles develop a certain tension, and shorten or stretch (lengthen); they can also remain at the same length, depending on the type of contraction.

Thus, a muscle contraction is an effect on the muscles that involves their fibers generating tension in themselves.As we have seen, this tension is produced in different ways, for example when the muscle is lengthened, shortened, moves, stays at the same length, etc.

Types of muscle contraction

Within the field of bodybuilding and training, we find different types of muscular contraction depending on the exercises we perform and the muscles we want to train and strengthen..

Here we are going to talk about the main types of muscular contraction that exist: isotonic contraction (which in turn is divided into concentric and eccentric), isometric contraction, auxotonic contraction and isokinetic contraction.

Isotonic contraction

The first type of muscular contraction is the isotonic contraction, also called heterometric, which consists of the most frequent contraction when we perform most sports. is the most frequent contraction when we perform the majority of sports, and the term "isotonic" means "of equal tension"..

The term "isotonic" means "of equal tension". In isotonic contractions, the muscle fibers contract and modify their length. In this type of contraction the fibers of our muscles are shortened and lengthened..

As we have already mentioned, isotonic contraction, in turn, is divided into two types of muscular contraction: concentric and eccentric.

Concentric contraction

In concentric contraction the muscle acts, generating tension, in order to overcome a given resistance..

Thus, there is a shortening of the muscle fibers and subsequently a mobilization of some part of the body. For better understanding, this type of movement would be like "concentrating" the muscle.

An example of concentric contraction would be an act as simple as taking a fork and bringing it to the mouthIn this case, we observe how our biceps swells (in this case, it is a concentric shortening). Another example, this time in the field of sport, would be to do certain exercises with weights, such as the dumbbell curl.

1.2. Eccentric contraction

In eccentric contraction, the second type of isotonic muscle contraction, the opposite occurs as in the previous case. In this case, in the face of resistance, we exert tension on the muscle while at the same time lengthening it.. Simplified, it would be like "extending" the muscle.

To illustrate, an example would be to lower the bar to the chest in a barbell exercise called bench press (in the concentric phase, we would raise the bar).

2. Isometric contraction

The second type of muscle contraction is the isometric contraction, which consists of a static contraction of the muscles. consists of a static contraction.

"Isometric" means "of equal measure or length". In this type of contraction, the muscle is static (i.e., it neither lengthens nor shortens, its length does not vary, as it does in other types of muscular contraction). In addition, a tension is generated in the muscle.

A clear example of isometric contraction would be to grabbing a toolbox and moving it from one place to another.This means that we generate a certain tension in our arms, which remain static (to prevent the box from falling). As we see in this example, the muscle fibers of the arms neither lengthen nor shorten, but are in a permanent position.

Another example of isometric contraction, in this case in sports (gym) exercises, would be to hold the bar (bench press) for a few moments.

3. Auxotonic contraction

Another type of muscle contraction is auxotonic contraction. In this case, the two previous types of muscular contraction (isotonic and isometric) are combined. In other words, for practical purposes: at the beginning of the muscular contraction, the isotonic contraction is produced, followed by the isometric contraction..

An example of auxotonic contraction is the stretching of elastic bands (extensors) with feet together (a type of exercise); in this case, we contract the muscles and hold them in the same position for a few seconds, and then return to the initial position.

In other words, we stretch the muscle gradually, and hold it in a certain position for a few seconds. There are many types of exercises to practice this type of contraction (as in the other cases).

4. Isokinetic contraction

Finally, the last of the types of muscular contraction is isokinetic contraction. In this case a maximum contraction of the muscle occurs, at a constant speed, throughout the muscle's range of motion..

This type of contraction is typical of sports that do not require acceleration of the movement, such as rowing or swimming. As we can see, in this type of sport a constant and uniform speed is required to move forward in the water. to move forward in the water.

To avoid confusion, we must be clear about the difference between isokinetic contractions and isotonic contractions (the former). When we perform isokinetic contractions, we constantly regulate the speed of the movement and exert maximum tension throughout. On the other hand, in isotonic contractions, we do not control the speed of the movement, nor do we always exert the same tension during the movement.

Bibliographical references:

• Correa, J.E. and Ermith, D. (2009). Principles and methods for muscle strength training. Textos de Rehabilitación y Desarrollo Humano Collection. Editorial Universidad del Rosario.
• Mora, I.S. (2000). Muscular system. Sabinamora.
• Vilanova, N.G., Martínez, A. and Monge, A.T. (2007). Muscle toning. Theory and Practice. Editorial Paidotribo.