Types and structural features of human muscles

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What do you know about human muscles?

Undoubtedly, many of you will answer that we need muscles only for strength and holding some kind of weights, both in the gym and in everyday life. For some, a purely aesthetic appearance. But human muscles are not so primitive that they would have only one purpose and be limited to this kind of only one power function. The task of the muscles lies in the ability to carry out the load of various types, for example, as long-term - quite light for a long time, but also short-term, but quite intense.

Today you testosterone cypionate Italia will be set a goal to run a marathon for several hours, tomorrow you will have a strength training process in the gym. And the muscles will perform both functions. The only difference will be how you do it and how quickly you give up in one of the types of load.

After all, agree? Not every load is given equally easily to every person. Especially if a person has never paid enough attention to training, let alone athletes.


What muscle fibers are responsible for our strength and endurance?

Based on these functions and functions of muscles, scientists at the Institute of Physiology of the United States as early as the twentieth century They suggested dividing the types of muscle fibers into several, depending on how fast they are contracting and how resistant they are to overwork (simply put, combining the two signs of fibers).

  • Glycolytic (or fast, i.e. quickly tired)
  • Intermediate (fast, very resistant to fatigue)
  • Oxidative (or Slow, Fatigue Resistant)

Fast glycolytic fibers. They contain a small number of capillaries, they are also called white, due to color, they are twice as thick as red fibers. They respond quickly enough to the signal that comes from the brain - twice as much as the slow ones.

The energy source is creatine phosphates, glycogen, ATP, which are 2-3 times more active in fast fibers, they are processed faster and give the muscles an energy boost faster. Unfortunately, at this time - these same sources are exhausted. Only less than 1 minute of active physical work is enough. Fast glycolytic fibers take energy without the use of oxygen, and this gives us almost lightning fast energy. Cons - running out of body reserves. Therefore, it is imperative after strength training to fill in glycogen reserves, as proteins and carbohydrates. In no case do not starve!

We conclude. White muscle fibers are designed for intense, but short-term load, they are not able to withstand multi-repetition in exercises and the same type of work for a long period of time.

Intermediate fibers. The number of mitochondria (energy-generating organelles of the cell) is significantly reduced, and glucose breakdown products, lactic acids, accumulate in the muscles during work, but fatigue comes much slower than glycolytic fibers.

Slow oxidizing fibers. They are called red (due to the large number of capillaries). They are activated and work with a long but light load. They contain more mitochondria and myoglobin, which are intended for the supply of energy and its gradual use.

The source of energy is fatty acids, fats.

Red fibers prevail among long-distance runners and athletes in other aerobic sports.

But the important difference between white glycolytic and red oxidative fibers is this: they are more able to increase in size and to some extent in quantity (individual fibers are separated during growth). The increase in muscle mass by 30-60% occurs mainly due to the growth of white glycolytic fibers.

The ratio of white and red muscle fibers.

This ratio lies deeply at the genetic level in each of us; changing it is almost impossible. A larger number of people are dominated by slow red fibers - 60 to 40 (%), and literally only a quarter of the ratio is the opposite - 40 to 60 (%). Can you imagine?

From people with prevailing fast fibers, very gifted sprinters, bodybuilders and professionals in all other sports where fast explosive strength is needed are obtained.

Is it worth it to focus only on strength training?

Or simply put, is it possible to create a training program focusing only on large weights?


Frequent work with heavy weight greatly depletes the muscles and central nervous system (CNS). And this is a significant minus. Our body needs a long recovery period (2-4 days).

Therefore, when playing sports, keep in mind that your personal trainer should competently approach to writing an individual training program for you, including necessarily, both heavy weights, medium weights and small ones, but with more repetitions and cardio training.

Remember, dear readers, that cardio cannot be removed from the training process in any way: the more muscle mass we have, the more the load on our heart increases.

Therefore, cardio is best done no more than 2-3 times a week for 20-30 minutes, but not every day. Such endurance training improves the ability of muscles to store glycogen and creatine phosphate.

The growth of white glycolytic fibers is the key to successful building a beautiful body and proportions, so strength exercises in the gym are central to the bodybuilder's training process. Be sure to remember that each exercise for an effective increase in muscle mass and power generation must be performed with the most appropriate technique in order to avoid sprains and tendons, and various other injuries.


You have learned that there are several types of muscle fibers in our muscles. The muscle does not function as a whole. Those people who have been engaged in fitness and bodybuilding for a long time should understand this. Muscles have fibers that are different in their "specialization."

There are two types of muscles that are responsible for endurance and are responsible for strength. Each muscle has both fast (white, denser) and slow fibers (red). And only genetically their ratio in each muscle can vary in different ways.

1. Someone is given good endurance, fatigue in active aerobic training (for example, distance) or static (fixing the position for a while), but poor performance in working with weights.

2. On the contrary, anaerobic training (gym, heavy weights) is easier for someone, the muscle response is much greater / muscle growth / strength than endurance (cardio, statics). And this is normal.

The main thing is to give the load on strength or endurance gradually.