Oxidative muscles. Types of muscle fibers and their functions

How many repetitions should you do to pump up? oxidative muscle fibers ?

In the last article I talked about white muscle fibers, now it’s time for red ones, because... they also make a big contribution to the development of maximum volumes. Working as a coach for several years, I noticed that only 10 percent of athletes train them, and most do not even know that they have the same potential for development as white people.

Training slow muscle fibers

Again, I won’t confuse you with a large amount of terms that are incomprehensible to you, I’ll just tell you how they need to be trained. If anyone is interested in why this is so, you can read Professor Siluyanov.

I highlight 4 basic rules for the development of these fibers:

1.The time under load should be from 30 to 50 seconds.

2.Partial amplitude. The muscles cannot be relaxed; they must be constantly tense. This is important for maximum acidification with lactic acid. During the approach you should feel a burning sensation.

3.Slow repetition speed.

4.Weight should be 30-50% of the one-time maximum. Otherwise, you will not be able to complete the required amount of work.

How many sets should you do for slow twitch muscle fibers?

Approaches should be from 2 to 5, with a rest of at least 5 minutes between them. But there are not just approaches here, but they are threefold. I'll explain now.

Do an approach in the range of 30-50 seconds, achieve a strong burning sensation, stop the approach, rest for 30 seconds, and start doing it again, then 30 seconds and a third similar approach. Now we have completed 1 long triple approach, there should be from 2 to 5 per workout. The advantage of these workouts is that they can be done at home. For example, push-ups or lifting small dumbbells to develop deltoids, biceps, etc.

When to train them?

I see 2 options here:

1. Train them after training fast muscle fibers. First you finish training the whites, only then we start the reds, this is very important point!

2. Do periodization.

In week 1 we train whites (low reps, 70-90% weight, explosive style, failure in the 7-30 second range).

On the 2nd week, red (Light weight 30-50%, slow and partial repetitions, time under load 30-50 seconds).

Friends, try it, experiment, who hasn’t tried it. I can say that this scheme will help you overcome plateaus in your progress.

They make a good contribution to increasing muscle volume, and if you have never trained them, this will help you gain extra centimeters in girth.

When training to burn fat or gain weight, you need to use different types muscle fibers. Read the article about what they are and how to determine the ratio of muscle fibers in the body.

When playing sports, we constantly use the word “muscles”. We talk about the fact that they work, they hurt, they grow or don’t grow, and so on. As a rule, our knowledge about muscles does not go further than this. However, it is very important to understand that muscles can be different in composition and are predisposed to different types of stress.

What are muscles?

A muscle is an organ that consists of fibers and is capable of contraction under the influence of nerve impulses sent by the brain through the brain-muscle connection. Accordingly, the main functions of muscle fiber in the context of sports are the implementation of movements and maintaining body position.

Muscle fibers There are two types - slow (MMV) or red, and fast (BMW) or white.

Slow-twitch (red) muscle fibers

These fibers are called slow fibers because they have a low contraction rate and are best suited for long, continuous work. They are surrounded by a network of capillaries that constantly deliver oxygen. These fibers are also called red because of their color. The color is determined by the protein myoglobin. This type of fiber is able to obtain energy not only from carbohydrates, but also from fats.

When are MMVs involved in their work?

IMVs begin to contract when performing various types of cardio exercise that require endurance:

Those. in all cases when you perform fairly long and monotonous work that does not require “explosive” efforts. This means that interval cardio training can no longer be classified as an example of exclusively MW work.

MMV training is aimed at:

increased stamina
getting rid of fat
increasing the number of blood capillaries

Fast (white) muscle fibers

By analogy with slow ones, one can guess that fast muscle fibers are capable of high-intensity, hard, but short-term work. These fibers use an oxygen-free method of obtaining energy, which means they use mainly carbohydrates. That's why they are white. Their rapid fatigue is due to the fact that during muscle fiber contraction, lactic acid is formed and it takes some time to remove it.

But white muscle fibers are also different.

Subtypes of fast muscle fibers:

subtype 2A or intermediate muscle fibers

They are also called transition fibers because these fibers can use both aerobic and anaerobic energy production. Essentially, it is something between red and white fibers.

subtype 2B or true BMW

These fibers use only anaerobic (oxygen-free) energy production and have maximum strength. They are capable of significant growth, so all recruiting programs muscle mass designed to work with these fibers.

When does a BMW start working?

This happens when you need to put in maximum effort in a short period of time. Those. during anaerobic training:

body-building
powerlifting
Weightlifting
sprint running and swimming
martial arts

These workouts help increase muscle volume by increasing the cross-section of the 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 matter and, as usual, different arguments are given in defense of each of them.

It is believed that the primary ratio of muscle fibers is genetically inherent in us and that is why some people find running much easier, while others find strength training. But on the other hand, by studying people involved in different sports, it was revealed that, for example, fast muscle fibers predominate in weightlifters, while slow muscle fibers predominate in marathon runners. Accordingly, it is assumed that training can slightly “redistribute” the ratio and number of muscle fibers in the body. Although, regarding the second approach, it is not entirely clear whether the reason for the predominance of certain fibers was a certain type of sport, or whether this choice of sport was a consequence of genetic inclinations.

Another important point to understand is that muscles and fibers are not the same thing. All large muscles bodies are made up of different types muscle fibers. There are no absolutely “fast” and “absolutely” slow muscles, just one or another muscle fiber may predominate in them.

How to determine which muscle fibers predominate

This can be done by sending tissue samples to a laboratory for testing, or you can do this yourself. muscle fiber ratio test. Let's look at how to do this using the example of the exercise, lifting dumbbells for biceps:

1) you need to select a weight of dumbbells at which you can perform only one repetition of this exercise - this will be Weight Limit
2) after this you need to rest for about 15 minutes and perform this exercise with a weight that is 80% of the maximum exactly as many times as you can do it without additional help
3) based on the number of times obtained, interpret the results
4) do the same with all major muscle groups

Interpretation of test results

To summarize, I want to say that you need information about the types of muscle fibers in order to understand what quality can be developed by using certain fibers. So, if the main goal is to develop endurance, then it is unwise to engage in strength training. And accordingly, by doing monotonous cardio, you will not be able to achieve an increase in muscle mass.

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Approximately 40% of the human body's weight is muscle. We need each of more than 600 muscles to perform vital functions: eating, breathing, walking, etc. For muscles to be strong, they need to be trained. And to determine the right type of training, you need to know that all the muscles of our body consist of two main types of muscle fibers, the features of the work and training of which the site will tell you in this article.

Different muscle fibers - different functions

Skeletal muscle consists of two main types of fibers:

Type I fibers are responsible for endurance, type II fibers (fast, glycolytic, white) are for strength and speed.
Type II fibers begin to work when physical activity requires more than 25% of maximum force.

Most people have approximately the same ratio of muscle fiber types, and it is determined genetically. However, fast fibers are larger in size than slow fibers and have a greater growth potential.

Genes determine three important factors regarding muscle:

Maximum number of fibers.
The ratio of muscle fiber types.
Shape of fully engaged muscles.

The ratio of muscle fiber types is determined genetically, and the dominant type can only be identified through an invasive muscle biopsy.

features and exercises for training type I fibers;
features and exercises for type II training.

Slow (I) type muscle fibers: structural and functional features

What you need to know about type I (slow) muscle fibers:

they contain mitochondria, which use oxygen to produce ATP, necessary for muscle contraction;
they are called red muscle fibers because they contain more myoglobin (an oxygen-binding protein), which makes them darker;
Since slow-twitch muscle fibers can provide their own energy, they can withstand small power loads for a long time, but are not able to provide significant strength;
This type of muscle fiber is characterized by a low activation threshold, i.e. they are the first to be activated during muscle contraction; if they are unable to generate enough force to perform a specific action, fast-twitch muscle fibers are activated;
tonic muscles responsible for posture have a higher density of red fibers;
Static endurance exercise can increase mitochondrial density, which helps increase the efficiency of using oxygen to produce ATP.

What exercises are suitable for training slow-twitch muscle fibers?

The characteristics of slow-twitch muscle fibers and their functioning allow us to determine the types of exercises that increase their aerobic activity. Such exercises are:

isometric exercises (example: plank), which keep slow-twitch muscle fibers in a contracted state for an extended period of time - thereby increasing the ability of such fibers to use oxygen to produce energy;
slow strength exercises with light weight, but more than 15 repetitions, in which aerobic metabolism is activated;
circuit training, in which one exercise replaces another with virtually no breaks;
exercises with own weight and a large number of repetitions also increases the efficiency of slow fibers;
When performing exercises with your own weight or light weight to train slow muscle fibers, it is better to reduce the break between sets to about 30 seconds.

For slow-twitch muscle fibers, slow exercises, high repetitions and light loads are suitable.

Fast (II) type muscle fibers: structural and functional features

Type II muscle fibers (white) are divided into fast fibers type IIa and IIb:

IIa (fast oxidative-glycolytic) muscle fibers use oxygen to convert glycogen into ATP;
IIb (glycolytic) muscle fibers use ATP from muscle cells to generate energy;
Fast muscle fibers are characterized by a high activation threshold, i.e. they are activated only when slow fibers unable to provide required amount strength;
Type II fibers reach peak force faster and can produce significantly more force than Type I fibers;
fast fibers are called white because they contain few capillaries;
white fibers “tire” faster;
phasic muscles responsible for movement are characterized by a high density of fast fibers;
Fast-twitch fibers are responsible for the size and expression of certain muscles.

What exercises are suitable for training fast-twitch muscle fibers?

Based on the characteristics of fast muscle fibers, we can conclude that exercises for developing explosive strength and strength training are suitable for training them, namely:

Strength training with heavy weights stimulates motor units and activates more muscle fibers; how more weight, the more fast fibers are used to lift it;
explosive movements with weights or using your own body weight - great way training white muscle fibers;
fast muscle fibers quickly get tired, so to achieve maximum efficiency during the exercise, it is recommended to limit the number of repetitions to 2-6;
Because this type of muscle fiber uses energy quickly, it requires a longer rest period (minimum 60-90 seconds between exercises) to recover.

Fast-twitch fibers determine muscle size, and explosive movements with weights are best suited for training them.

Understanding how the body adapts to stress allows us to develop the most effective program workouts tailored to your individual needs.

Greetings to all our honest brethren! Today we will continue to tedious, because we are waiting for a continuation, the second part, notes called “Types of muscle fibers.” From it you will learn everything about the practical aspects of training of one type or another, identify which fibers predominate in you, and how, in connection with this, you need to build your training process and select exercises.

So, if everything is assembled, then let's begin.

Types of muscle fibers: how to identify dominant ones and train effectively?

Of course, our note would not be complete if we did not consider practical side question, so let's continue our broadcast in this vein. But before that, read through so that no questions arise. Ready? Now let's start by considering the following question...

Number of repetitions and fibers involved.

The following guide will help you determine the number of repetitions and the type of muscle fibers involved in the work.

No. 1. Development of maximum power.

1-3 . The load is high and amounts to 95-100% from a one-rep max. This training scheme leaves Type IIA and mostly Type IIB fibers in play to complete the last rep. It is most common among the strongest powerlifters. With it, myofibrillar hypertrophy occurs, associated with an increase in protein in the muscles due to satellite cells that help increase the number and size of contractile proteins (actin and myosin). The number of muscle fibers remains the same, but satellite cells fuse with existing cells and donate their nuclei and DNA to help the muscle fibers grow in size.

No. 2. Strength training.

Number of repetitions to failure 2-6 . Intermediate and Type IIB fibers are used to complete repetitions. This training scheme is suitable for those who want to increase their strength and develop anaerobic endurance. Myofibrillar hypertrophy occurs due to satellite cells, an increase in the contractile proteins actin and myosin.

No. 3. Training for the development of hypertrophy.

Number of repetitions to failure 8-20 . This training scheme forces type I, intermediate and type IIB fibers to be activated. Unlike training No. 1 and No. 2, hypertrophy occurs not due to the myofibrillar apparatus, but due to the sarcoplasmic apparatus, increasing the amount of sarcoplasm. The number of repetitions and weights used to perform a given number of repetitions will ensure growth potential for all fiber types.

No. 4. Development of endurance.

Number of repetitions 20 and more. Type I fibers are endurance fibers that recover quickly compared to fast-twitch fibers. The perfect workout endurance training should include approaches 90 seconds using the weight without feeling any failure during that time. In other words, in order not to provoke the activation of stronger muscle fibers - intermediate and fast-twitch, it is necessary to use light weights and not strive for failure in repetitions. In this case, you can only hope to train type I fibers.

Types of muscle fibers. How to train correctly? General tips.

The following tips will help you navigate your training strategy and use of training principles.

So remember:

to develop type I fibers, you need to spend more time per week aerobic training, in particular, in the ratio 4 against 1-2 power;
Type IIA fibers respond well to growth during long-term anaerobic training using supersets, giant sets, drop sets;
If your goal is to lose weight, and you have predominantly red (slow) fibers, then you need to focus on running at a moderate pace over long distances. In this case, thanks to the aerobic method of obtaining energy, fats are burned;
if your goal is to increase strength and the number of white type IIB fibers, then you need to train in the range 3-7 repetitions;
In order for fast-twitch fibers to come into play and muscle mass to increase, it is necessary to train intensively, because only in this case fibers with large motor neurons (type II) are included in the work;
number of repetitions in range 8-12 in combination with a high degree of intensity of the entire workout will have the maximum effect on increasing muscle size;
strength training for the development of fast-twitch fibers involves short approaches (before 7 repetitions) With several ( 2-4 ) minutes of rest;
continuous loads from 40 minutes in aerobic zone pulses are aimed at burning fat and involving slow fibers;
workouts on an empty stomach (with low glycogen levels) aimed at training type I fibers.

Actually, all this time we have been talking about the types of muscle fibers and training schemes, but how can we find out which type of fibers predominates specifically in us? The next subchapter will help with this.

Pregnancy test fast/slow muscle fiber ratio

Bodybuilding, oddly enough, also has its own tests, and some of them do not require any handy equipment. So, in particular, in order to identify the type of muscle fiber that predominates in an athlete, the following test is performed - the limit of repetitions of a muscle compared to its maximum strength. The meaning is this:

choose 1 insulating (conditional isolation) exercise for a specific muscle group, for example, biceps - lifting a dumbbell with one hand / EZ-bar with two;
select the weight of the projectile so that you can perform “cleanly” independently only 1 repetition ( 1 RM);
rest 3-5 minutes;
take a weight that is 80% from 1 R.M. (to do this, multiply the maximum by 0,8 ) and perform as many repetitions as possible.
4 before 7 , then you have predominantly fast (glycolytic) muscle fibers that are strong but not durable;
if the number of repetitions is 10 , then there is parity of fast and slow fibers;
if the number of repetitions falls within the range of 12 before 15 , then you have a predominance of slow (oxidative) muscle fibers.

Let me explain more popularly what it’s about we're talking about. For example, you need to determine which fibers predominate in your biceps brachii muscle. you were able to raise 1 dumbbell biceps times with weight 30 kg means 1 RM= 30 kg, 80% will be 24 kg. Then you rested and completed a set of reps 13 , therefore, your biceps are inhibitory :), because consists predominantly of red muscle fibers.

Using such an algorithm, you need to go through each muscle group and, using your isolation exercises, identify the type of predominant muscle fibers. Having such data, it will be easier for you to build your workout and achieve maximum output from your muscles.

I think a reasonable question has arisen: what isolation exercises can be used for each muscle group. You will find the answer in the following memo.

In the text version, exercises for muscle groups look like this:

chest - on a horizontal bench;
biceps - / lifting dumbbells for biceps;
triceps -;
back - traction upper block to the chest while sitting;
shoulders – ;
front surface of the thigh – leg extensions in the simulator;
back surface hips - .

Muscle groups by fiber type

Agree, it would be interesting to know how to train this or that muscle group in the key of knowing the types of fibers corresponding to it. After all, in this case, the training turns out to be more meaningful, and you can try it yourself.

In this regard, I have compiled a kind of generalized atlas muscle groups by type of muscle fiber. That's what he is.

As for some of the features of muscle fiber types (m.f.) of muscle groups, they are as follows:

hamstrings and gluteus maximus are of the mixed type, with a predominance of slow m.v. Therefore, they must be loaded with a higher number of repetitions to failure;
soleus consists of 70% , and the gastrocnemius is on 55% from red m.v. (i.e. she is a borderline mixed type with a slight predominance of slow m.v.). Therefore, due to the fact that seated calf raises load the soleus, it is necessary to perform more repetitions to failure when training it. In turn, calf training should be approached with a small number of repetitions (up to 8 ) , but with a lot of weight, so standing calf raises must be performed with maximum weights;
the anterior surface of the thigh is a fairly individual muscle group, in which the types of muscle fibers vary and are mixed from fast to slow. The rectus femoris muscle predominantly has fast-twitch movements. Therefore, squats (multi-joint movement) Barbell exercises on the chest/shoulders should be done with heavy weights but low reps. However, when performing extensions in knee joint sitting in the gym (single joint movement) the best option would be a combined approach to loading;
deltoids are a mixed fiber type with a red bias, so it is best to train them using a combined approach, with an emphasis on a higher number of repetitions until muscle failure;
biceps, triceps, pectoral muscles - white muscles predominate in these muscle groups, so it is better to work them with an emphasis on high load and low number of repetitions;
The latissimus dorsi muscle has almost perfect balance ( 50/50 ) mixed with fast and slow movements, so the “wings” need to be worked out using a combined approach;
the press is an intermediate type with a predominance of fast twitch fibers, therefore it is more advisable to use a combined approach when training the abdominal muscles;
trapezius and back extensors - they are dominated by oxidative fibers, these are hardy muscles that need to be “pounded” with a large number of repetitions.

Now let's talk about...

Muscle Fiber Types and Recovery

An important aspect of training is understanding the issues of recovery of muscle groups depending on the types of predominant fibers. So, when talking about fiber restoration, we will always keep the following reminder in mind.

Here are some clarifying points:

IIB fibers are recruited only during the last 2-20 seconds of contraction, near muscle failure (depletion of muscle resource);
the recovery time of IIB fibers is about 4-10 days, for this reason there is no point in going to Gym for training fast fibers;
if strength training was resumed before type IIB fibers were restored (for example, after 3 rest days), then you will feel that muscle exhaustion will occur much earlier than in the previous session. A certain part of the fibers will be, as it were, “canned” and will not be available for “hire”. Recovery, repair and growth of muscles occurs only after sufficient rest;
Unlike Type IIB, Type I hardy fibers become available for recruitment after 90 seconds of rest.

Conclusion: in connection with the above calculations, the optimal training strategy is to use moderately heavy scales. This allows for rapid progression across all types of motor units (fiber types), recruiting them into action - not so fast that only the white fibers receive the bulk of the stimulation, and not so slow that the red and intermediate motor units can recover. Thus, it turns out that for the fullest impact (total coverage) for the entire spectrum of muscle fibers, the weight of the weight should not be light, but not too heavy.

These were general calculations, now let's go specifically through each type of fiber and identify the optimal number of repetitions and time of work under load.

Types of muscle fibers: optimal time under load and number of repetitions per set

To make it clearer and clearer, let’s summarize all digital and text data into a consolidated table. As a result, we get the following (clickable).

Remember which fibers predominate in you, and what characteristics this or that type has, this will help you determine the quantitative parameters of your training.

So, in this regard, it will be useful to know how to train in the light of the inherited bodily inheritance. This is what we will look into. Let's start with body type...

No. 1. Ectomorph.

A lean type with long limbs and a predominant red type of muscle fiber. That is why these representatives slowly gain muscle mass, because... their fibers inhibit and there are many of them. At strength training You can expect an increase in strength and, to a lesser extent, muscle mass. In general, the ectomorph needs to focus his efforts on stimulating the RMV (fast m.v.), and although the ratio between the RMV and the RMV does not change much (within 10% ) As a result of training, the ratio of the masses of these fibers can be controlled quite well. Those. if the ectomorph has a conditional ratio of BMW and MMV before the start of training = 20:80% , then during exercise the “specific gravity” of fast fibers will increase. In other words, proper training will promote hypertrophy of white fibers and atrophy of red fibers. And, as a result, such an athlete potentiates his muscle growth.

Conclusion: the ideal number of repetitions per set is 4-8 .

No. 2. Mesomorph.

Lean and generally athletic body type, with a high percentage of fast-twitch muscle fibers type 2A and 2B. When doing strength training, you can expect an increase in both strength and volume indicators.

No. 3. Endomorph.

Round stocky athletes with a high percentage of fiber fast type 2B. With strength training, you can count on an even greater increase in strength, with an adjustment towards increasing muscle mass.

Mesomorphs and endomorphs initially have more muscle mass, so to increase muscle mass they just need to push themselves a little.

Conclusion: perfect (in terms of increasing muscle mass) the number of repetitions for a mesomorph is 8-12 , endomorph 12-15 for the approach.

The general rule for increasing muscle mass is high intensity training, because it is this that allows you to turn on (last reps) fast-twitch muscle fibers responsible for hypertrophy. And in light of the fact that white fibers have a much larger surface area than red ones, muscle volume will grow better. Thus, it turns out that training to increase muscle mass involves high intensity in the range of failure repetitions at 8-12 once.

Well, in conclusion (or are you already asleep? :)) Let's consider a training scheme for maximum development of fast muscle fibers.

How to use white muscle fibers to the maximum? Training scheme.

A bunch of scientific research come to the conclusion that the following training scheme - split - can achieve maximum BMW recruitment:

workout #1: 1-5 repetitions, 3-5 minutes of rest, multi-joint exercises;
workout #2: 8-12 repetitions, 60-90 seconds of rest, only multi-joint movements;
workout #3: 12+ repetitions, 30-60 seconds rest, supersets, multi-joint and isolation movements.

In other words, one workout per week should be strength training (lifting) and consist of exercises - deadlift, squats, bench press, pull-ups, dips, shoulder presses and barbell rows. The other is classical bodybuilding with a number of repetitions 8-12 and the third - intense pump with exercises in the style of a train (supersets).

Phew, actually, that’s all I have, now let’s sum up all this chatter and say goodbye.

Afterword

Well, we have completed the boring technical note about the types of muscle fibers. Well done for reading to the end, now you know what types of fibers there are, how to identify them and stimulate them to grow. All this will help you maximize your muscle potential and achieve the physique you always wanted. That's all, I was glad to fall asleep to write for you, see you!

PS. Do you divide your training by fiber type?

P.P.S. Attention! 22.03 The ability to send questionnaires for and food will become available. I will be glad to see you working together!

With respect and gratitude, Dmitry Protasov.

It’s unlikely that anyone will object that middle and long distance running requires strength training, which has its own specifics. To carry it out correctly, it is necessary to take into account the presence of fast and slow fibers in the muscles.

The editors offer readers a series of conversations with a candidate of biological sciences, head of the problem laboratory of the Russian State Academy of Physical Culture Viktor NikolaevichSeluyanov, which for a long time deals with the study of the properties of muscles, muscle fibers, characteristics of strength development and, in general, an original approach to training runners for medium and long distances.

- Viktor Nikolaevich, I would like to start the conversation with basic concepts. What is muscle composition?

Athletic performance in middle and long distance running depends on aerobic capacity, more precisely, on the anaerobic threshold, running power and the amount of oxygen consumption at the anaerobic threshold. Research shows that these indicators are directly related to muscle composition. The more oxidative muscle fibers an athlete has, the higher the anaerobic threshold.

Muscle fibers can be classified in at least two ways. The first way is by the speed of muscle contraction. In this case, all fibers are divided into fast and slow. This method determines the hereditarily determined muscle composition. It can be used to determine the future specialization of the athlete. In general, middle- and long-distance runners have a higher proportion of SMV (slow-twitch muscle fibers). Averages - 50-70%, stayers - 70% and above.

There is a second method of classification. If in the first case the assessment is based on the enzyme of myofibrils (myosin ATPase), then in the second - on the enzymes of aerobic processes, on the enzymes of mitochondria. In this case, muscle fibers are divided into oxidative and glycolytic. Those muscle fibers in which mitochondria predominate are called oxidative. Almost no lactic acid is formed in them.

In glycolytic fibers, on the contrary, there are very few mitochondria and during their work a lot of lactic acid is formed. The more lactic acid, the greater the acidification, the sooner local fatigue occurs.

The results of these two methods are not necessarily the same. The coach’s task is not to change heredity, but to make sure that the athlete has more oxidative MVs, which can be changed. With properly structured training, the number of oxidative fibers in an athlete can increase, since the mass of mitochondria in glycolytic MVs begins to increase and they gradually become more aerobic, consume more oxygen and eventually stop producing lactic acid. Why is this happening? Because intermediate products, for example, pyruvate, are not converted into lactate, but enter the mitochondria, where they are oxidized to water and carbon dioxide. Such athletes show outstanding results if there are no other limiting factors.

- How to determine muscle composition in practice?

International standard - take a piece muscle tissue(usually from the thigh muscles - the outer head) and biochemical methods determine how many fast and how many slow fibers. The same portion is subjected to another analysis, in which the amount of respiratory enzymes is determined.

In our laboratory, still under the leadership of Yu.V. Verkhoshansky developed indirect, indirect methods, carried out on a universal tensographic stand. We used it to determine the rate of strength growth and it turned out that it was related to the number of fast and slow fibers. Then the same studies were carried out by Komi in Finland. He found a correlation between the muscle composition in terms of the speed of contraction and the steepness of the increase in strength. But we went further and divided the force gradient by the force itself, that is, we got a relative indicator that works well. Moreover, it may be a more accurate method than a biopsy, since we directly measure the rate of muscle tension.

We separate long distance runners and middle distance runners based on this indicator. In stayers, the slow muscles are both the anterior and posterior muscles surface of the thigh, and in 800 m runners, the muscles of the front surface of the thigh are as slow, and the back ones are fast, like those of good sprinters. Therefore, they quickly run 100 m on the run, and it is these muscle fibers that they save until the very finish.

-So, if we take a biopsy from the quadriceps femoris muscle, we can sometimes make mistakes? Fiber ratio different muscles not the same?

Absolutely right. Recently, a lot of materials have accumulated that indicate that if one muscle is slow, say, the rectus femoris, then it is not necessary that all the others are the same. Interestingly, sprinters have a front thigh that is neither fast nor slow. Therefore, we can assume that their posterior surface is fast, it cannot be otherwise, but the biopsy is still taken from the anterior surface of the thigh and the results for sprinting are incorrect.

- And according to your method?

According to our method everything is fine. In sprinters, the front is quite fast and very strong, and the rear is even more so. If we take jumpers, then they have up to 90% fast fibers in the anterior thigh - this is their main muscle. But in running, the back surface is still more important, and that’s why it tears.

- If you go down to the muscles of the lower leg, what are they?

Sprinters have not only a fast gastrocnemius, but also a fast soleus muscle. How longer distance the more slow fibers there are. One experienced trainer He told me that schools are looking for guys with fast feet.

- Tell us about the pattern of muscle work in competitive running, say, in the 800 m race .

From the start the athlete goes to the desired<крейсерскую>the speed required to run, let's say it takes 15 seconds. The runner recruits almost all the fibers in the working muscles, which spend their ATP and creatine phosphate. Once he reaches this speed, muscle activity decreases to the amount necessary to maintain the desired speed. Consequently, those fibers that have done their work (as a rule, these are fast or glycolytic) are switched off from work and begin to rest and restore ATP, and the runner moves for 30-40 seconds at the expense of those muscles that provide this speed, but they have a reserve of ATP also begins to decline, and aerobic processes cannot provide the given power, and the runner begins to connect more and more new motor units. If by 600 m he still has fast fibers left in reserve, he will be able to increase, if he has exhausted muscle resources, he will only be able to maintain the speed, which will begin to fall, since it includes not only oxidative fibers, but also the fastest glycolytic fibers that form lactic acid, hydrogen ions. This prevents the muscles from contracting, and no matter how much the runner wants to finish quickly, nothing will happen - the speed will decrease.

The ideal runner should be strong and have no glycolytic fibers. The higher the anaerobic threshold and the closer it is to maximum oxygen consumption, the higher the result will be. A striking example was New Zealander Peter Snell, who used hill running a lot in his training, which increases the number of mitochondria in glycolytic fibers and guarantees such a high level of aerobic capacity that he could not acidify until the very finish. Therefore, with low speed abilities, he managed to run very quickly at the end of the distance.

- So we can say that the strategy for preparing a middle-distance runner from the point of view of muscle development is to increase the strength of the IMF and convert glycolytic fibers into oxidative fibers.

Yes. This is not a change in the hereditary muscle composition, but an attempt to increase the mass of mitochondria and the diameter of the MM.

-You remembered Peter Snell, but now we have Yuri Borzakovsky, who starts the 800m calmly and then finishes very quickly. It can be assumed that it also does not acidify.

Apparently this is true. I would be happy to examine him and give some recommendations. If a person has 100% oxidative fibers, then his tactics for passing the distance are clear - he accelerates to<крейсерской>speed and then maintains it until the end. But such people are rare or, as a rule, they are stayers. If people are strong enough, but their muscles are not sufficiently developed and they have glycolytic fibers, it is better for them to start at an optimal pace, maintain this speed until the finish, and then show what is still in the fast fibers. But glycolysis only works for 20 seconds, so the start of the spurt should begin no more than 150 m before.

- Let's now talk about strength training methods.

In classical strength work with maximum weights, both slow and fast fibers are used, but only the fast fibers are trained. Since the regime is dynamic (periodically with muscle relaxation), blood flows through the oxidative muscle fibers, removes hydrogen ions from there, and without them the strength does not grow in them. You need to slightly acidify the muscle, otherwise it will not gain strength.

- It’s surprising that slow fibers work, but there is no effect.

The laws of physiology require the recruitment of all MVs, but other biological laws related to the synthesis of myofibrils require the presence of hormones, creatine, this is always there, but hydrogen ions open the pores and it is easier for hormones to reach the DNA. Where there is a lot of oxygen, where there are a lot of mitochondria, hydrogen ions simply disappear. They are formed in fast fibers, pass into slow ones and disappear there. Therefore, the main stimulator of strength development for slow fibers is not present in the dynamic mode.

- Then the question arises, how does the development of fast fibers proceed if the hydrogen ions all go into the slow fibers and disappear there?

Hydrogen ions are formed in glycolytic (fast-twitch) muscle fibers and can diffuse into adjacent muscle fibers and blood. Therefore, in fast muscle fibers there are hydrogen ions, and in oxidative (slow) muscle fibers, hydrogen ions are converted into water with the participation of mitochondria.

- How then to increase the strength of slow muscle fibers?

In our laboratory we came up with exercises that we called stato-dynamic, without muscle relaxation. For example, squats with a barbell with a light weight, even with a barbell. But they need to be performed slowly and not straighten your legs completely, without giving the thigh muscles the opportunity to relax at least for a moment. After performing such squats, within 30-40 seconds the muscles get tired and pain appears.

- Is it really possible that fast fibers don’t turn on in this mode?

Electromyograms indicate that muscle activity in this mode is about 50%; as you get tired towards the end of the exercise, it increases, but does not reach a maximum, which indicates that fast MVs are not recruited.

- But at the very beginning of our conversation, you said that practically no lactic acid is formed in slow muscle fibers. Where does this acidification come from then? Maybe it’s the fast-twitch fibers that work in such exercises?

If a muscle is tense, the muscle fibers compress the capillaries and blood stops flowing through them into the muscle. After a few seconds, hypoxia begins, so anaerobic glycolysis begins in all cells, including oxidative muscle fibers, and lactic acid is formed.

- After such training, does MMV hypertrophy occur?

Of course, but you need to take into account that slow fibers can occupy only a third of the muscle, and the diameter of slow muscle fibers is 30-40% smaller than fast ones. Therefore, this happens imperceptibly at first, as the density of myofibrils increases due to the appearance of new ones, then the diameter also increases when mitochondria appear around new myofibrils. But mitochondria occupy only 10% of the total muscle volume. The main growth is due to myofibrils.