Types of muscle fibers and their functions
During training for fat burning or mass gain, you need to use different types of muscle fibers. About what they are and how to determine the ratio of muscle fibers in the body, read the article.
When playing sports, we constantly use the word “muscles”. We are talking about the fact that they work, hurt, grow or not grow, and so on. As a rule, our knowledge about muscles does not go beyond this. Nevertheless, it is very important to understand that the composition of the muscles can be different, and are prone to various kinds of load.
What is muscle?
A muscle is an organ that consists of fibers and is capable of contracting under the influence of nerve impulses sent by the brain through a brain-muscle connection. Accordingly, the main functions of muscle fiber in the context of sports are the implementation of movements and maintaining the position of the body.
Muscle fibers are of two types – slow (MMB) or red, and fast (BMW) or white.
Slow (red) muscle fibers
These fibers are called slow because they have a low rate of contraction and are maximally adapted to perform continuous continuous work. They are surrounded by a network of capillaries that constantly deliver oxygen. Also, these fibers are called red because of their color. Color determines the protein myoglobin. This type of fiber is able to receive energy not only from carbohydrates, but also from fats.
Fast (white) muscle fibers
By analogy with slow ones, one can guess that fast muscle fibers are capable of high-intensity, heavy, but short-term work. These fibers use an oxygen-free method of generating energy, which means they mainly use carbohydrates. That is why they are white. Their rapid fatigue is due to the fact that during the contraction of muscle fiber lactic acid is formed and in order to remove it, it takes some time.
But white muscle fibers are also different.
Subtypes of fast muscle fibers:
subtype 2A or intermediate muscle fibers
They are also called transitional, because these fibers can use both the aerobic and anaerobic methods of generating energy. In fact, this is something between the red and white fibers.
subtype 2B or true BMW
These fibers use only the anaerobic (oxygen-free) method of generating energy and have maximum strength. They are capable of substantial growth, therefore, all muscle-building programs are designed to work on these fibers.
When do BMWs get involved
This happens when you need to make maximum effort in a short period of time. Those. during anaerobic training:
sprinting and swimming
These workouts help increase muscle volume by increasing the cross section of muscle fiber.
BMW training is aimed at:
increase in strength
increase in muscle mass
Can the ratio of fast and slow muscle fibers in the body change
There are several opinions on this subject, and, as usual, various arguments are made in defense of each of them.
It is believed that the primary ratio of muscle fibers is laid in us genetically and that is why some people are much easier to run, and others power load. But on the other hand, while studying people involved in various sports, it was revealed that, for example, fast muscle fibers prevail in weightlifters, and slow in marathon runners. Accordingly, it is suggested that training can slightly “redistribute” the ratio and number of muscle fibers in the body. Although, with respect to the second approach, it is not entirely clear whether a particular sport was the reason for the predominance of certain fibers, or whether this choice of sport was, after all, a consequence of genetic inclinations.
Another important point to understand – muscles and fibers is not the same thing. All large muscles of the body are composed of different types of muscle fibers. There are no absolutely “fast” and “absolutely” slow muscles, just this or that muscle fiber can predominate in them.
How to determine which muscle fibers prevail
This can be done by submitting tissue samples to the laboratory for research, or by independently testing the ratio of muscle fibers.
To summarize, I want to say that you need information and types of muscle fibers in order to understand what quality can be developed by using these or those fibers. So, if the main goal is the development of endurance, then it is unreasonable to engage in strength training. And accordingly, performing a monotonous cardio, you can not achieve an increase in muscle mass.