Types of muscle fibers and their functions. Myths about fast and slow muscle fibers

Myths about fast and slow

It is customary to separate muscle fibers into two main types:

red = slow and white = fast.

In modern biochemistry, it has recently become common practice to divide fibers into fast and slow - each fiber is innervated by a certain number of nerve impulses. The more nerve impulses, the higher the ATPase activity, the faster the fiber contracts.

As for the color. Myoglobin in a muscle cell performs the same functions that hemoglobin performs in blood plasma - it carries oxygen.

Regardless of ATPase activity, fibers are divided into oxidative and glycolytic. So far, biochemists have not found red (myoglobin-rich) fibers that have high ATPase activity. Therefore, the division into red-slow and white-fast is very arbitrary.

Almost all biopsy samples showed that slow fibers are much superior in development. The conclusion is quite logical - the growth potential of fast ones is much greater than that of slow ones. Empirically, more or less many have come up with a fairly effective method for developing fast fibers - explosive force and work at the level of 80-90% of the maximum maximum strength and you are guaranteed significant hypertrophy of this type of fibers.

Bodybuilders have, step by step, found the path to hypertrophy of slow fibers - a large number of repetitions when working at lower levels of 20-40% (or 10-50%) of strength leads to acidification and failure - it is this state that corresponds to the optimal concentration of hydrogen ions, in combination with volume training (from 4 to 12 approaches for each muscle group) - this resulted in the growth of slow fibers.

Biopsies (samples of muscle tissue) of professional bodybuilders prove that red fibers reach absolutely such same dimensions in diameter as fast ones. Slow ones muscle fibers grow no worse than fast ones. You just need to train them correctly.

2 Myth. It is believed that fast fibers develop much more force than slow ones. In other words, fast ones are stronger than slow ones.

fast fibers are turned on only when the force is explosive or the weight exceeds 80% of the maximum force limit. Therefore, the conclusion suggests itself that they are strong - stronger than the slow ones. The biopsy almost always “protruded” on the side of the fast fibers - their diameter was usually larger. And if it’s thicker, it’s stronger. BUT slow ones can be just as thick as fast ones, which means they can develop no less strength!

It is believed that fast fibers develop because due to the high activity of the ATPase enzyme there are more bridging connections per unit time. This is true - but only for a unit of time, that is, if given time, they will develop the same effort.

The slow ones are capable develop such the same effort as fast fibers(all other things being equal - fiber thickness, etc.) !

Slow ones grow just as easily as fast ones - you just need to develop them correctly.

Hello! What tricks will the body go to in order to save energy in order to increase our survival. Although, judging by the way the population is growing, sometimes you think that it would be better for him not to do this. Ha ha. But seriously, everything in our body is balanced and optimized. The body will never do anything that is not beneficial to it.

A little about saving energy

As I said, the body does everything to:

1. Save as much energy as possible(This is why we store excess energy as fat).
2. Spend as little energy as possible in any task(that's why we are all lazy by nature).

This allowed us to survive for TENS OF THOUSANDS of years. Our ancestors could enjoy the meat of a killed animal for one week, and then practically starve for two or more weeks, eating only roots (farming appeared later).

Therefore, our body WAS TAUGHT that in order to survive in the harsh conditions of natural selection (predators, diseases, hunger, etc.) IT IS NECESSARY TO SAVE THE ENERGY RECEIVED!

He does this whenever possible, for example:

• Nutrient accumulation system (we store excess food in fat and do not remove it from the body);
• Muscular adaptation (muscles will not grow without increasing the load, i.e. without a STRONG need to warn yourself from danger);
• Hair on the body, calluses on the hands from constant work, tanning from the sun (even this was done to save energy, since this is also a forced adaptation to external influences);

The body adapts ONLY WHEN NECESSARY, such as: “It’s better to grow hair on your body than to freeze from the cold,” “It’s better to grow calluses on your hands than to get blood poisoning and die,” etc. It won’t do this if you don’t care. need to! It SAVES ENERGY!

What can I say, EVERYTHING IN OUR BODY IS MADE TO SURVIVE BETTER IN THE ENVIRONMENTAL CONDITIONS! If the body can save energy somewhere, it will do it! Therefore, it is always more convenient for us to walk than to run; stand rather than walk; sit rather than stand; lie down, rather than sit, etc.

As you probably already understood, LAZINESS- This is also an ADAPTATION MECHANISM of the body to save energy.

It was in order to save energy that our body created another amazing mechanism - different types of muscle fibers.

In order to save energy, muscle fibers in our body are heterogeneous.

What is the point of dividing our muscles into different types of muscle fibers? VERY BIG!

Look, as a rule, in life we ​​have different types of physical activity, namely:

1. Very heavy (for example, you need to move a very heavy piano).
2. Medium in weight, high-volume (for example, carry a lot of medium-heavy bags of potatoes).
3. Easy (long, monotonous run).

Is it beneficial for our body, for example, to use the ENTIRE HUGE MUSCLE MASS OF THE LEGS for a light load? Naturally, NO!

It is for this purpose that our body has created “different workers” to perform work of different types.

1. Fast-twitch muscle fibers (FMTs).
2. Slow-twitch muscle fibers (SMF).

But! There are also fibers that are designed to perform EXTREMELY HARD WORK, namely HIGH THRESSION fast muscle fibers (HFTF).

Those. we get three main types of muscle fibers:

To more clearly imagine the situation, why the body needed such transformations, imagine that our ancestors were going hunting.

Here they are slowly moving through the forest and, in their opinion, are in complete control of the situation. AND SUDDENLY a PREDATOR – A SABER-TOoth TIGER – jumps SHARPLY out of the bushes at one of them!

The man is SCARED TO DEATH and in a split second he jumps to the side so as not to die. At this moment, HIGH-THRESHOLD FAST MUSCLE FIBERS, which were created to perform extreme work and to respond instantly, were activated.

But the predator does not give up and begins to run after the Cro-Magnon man. This is where FAST MUSCLE FIBERS come into play, allowing you to gain fast speed in a short time!

But the predator does not give up and continues to pursue the unfortunate bare-assed hunter. After a certain time, the hunter’s body understands that it will take a long time to run and turns off fast muscle fibers, while connecting SLOW MUSCLE FIBERS to perform monotonous, long work (running).

Well, to hell with it, let there be a happy ending. The man ran to the cliff and jumped into a deep river and swam away to his fellow tribesmen.

That's how it is, guys. Got it? During physical activity, our body does not use all the fibers of the working muscles at once., but uses only those that are necessary for him to perform SPECIFICALLY GIVEN TYPE OF WORK! And all because this way he can save more energy. Part of a muscle spends less energy than the entire muscle! Elementary.

I want to make one caveat. Endurance fibers can be either fast-twitch or slow-twitch muscle fibers, and fast-twitch fibers can be both durable and easily fatigued.

However, for ordinary people who play sports at an amateur level or who do not play sports at all, this will be exactly the case. MMVs are likely to be more durable than BMWs, because... they will have much more mitochondria and mitochondrial enzymes.

Mitochondria, in turn, are capable of obtaining “energy” from the oxygen (respiration) and reagents (fats or pyruvate) at their disposal as a result of chemical transformations - the same ATP that provides almost all energy-consuming processes in our body.

The purpose of different types of muscle fibers

Let's take a closer look at the different types of muscle fibers. So:

• High-threshold fast muscle fibers (HTF)– designed for VERY HEAVY WORK and QUICK INCLUSION into work with SUBMAXIMUM weight. They use fast energy sources for their contraction, which are capable of rapid resynthesis (creatine phosphate and glycolysis). When an athlete lifts a barbell with weight 1 time, i.e. 1 repetition maximum (RM), then all this is the work of HIGH THRESHOLD BMWs. To prevent you from breaking yourself, nature came up with a similar mechanism, a “quick response team,” if you like. These fibers are very strong and WHITE.
• Fast-twitch muscle fibers (FMT)– designed to perform HEAVY and HIGH-VOLUME work with MODERATE-HEAVY WEIGHT (6-12 repetitions). They are used for reduction, just like VBMW, fast sources of energy. These fibers are also called WHITE and they are used by all athletes of speed-strength sports (BB including).
• Slow-twitch muscle fibers (SMF)– they are designed to perform light, long, monotonous work. Perform SLOW and LIGHT contractions. Therefore, they use slower but more economical energy sources. One of these is OXIDATION OF FATS WITH THE HELP OF OXYGEN. This provides noticeably more energy than glycolysis, but requires more time, because The oxidation reaction is very complex and requires a lot of oxygen, which is why MMFs are called RED MFs (because oxygen is carried by hemoglobin, which gives the fibers their red color). These are the fibers that are primarily used by marathon runners, cyclists, etc.

So, should you even bother training other muscle fibers?

Do you need to train all muscle fibers?

If you are a beginner bodybuilder, then PROBABLY NOT! Your body is not yet accustomed to the load and has not even learned , designed for such work FAST MUSCLE FIBERS.

BUT! If you have already been working out in the gym for 2-3 years and have stagnated in the results, then training slow muscle fibers can cause very good progress!

It would seem that if a person runs marathons, then it is logical for him to train MMB, and if he works with very heavy weights, then BMW and VBMV. But it's not that simple, friends.

Body-building- a very specific sport, where to achieve maximum performance, all means are good (from training different types of muscle fibers and microperiodization to the use of very large doses of pharmacology).

ONE WHOLE IS ALWAYS BIGGER AND STRONGER THAN A PART! If we develop all the muscle fibers, then it is logical that the muscle will be larger overall.

Previously, it was believed that there was no point in training IMM. The fact is that when a BIOPSY (sample of a small part of the muscle) was taken from athletes of Olympic sports (weightlifting, sprinters, javelin throwers, etc.), they noticed that, as a rule, there are many times more fast muscle fibers, than slow ones. Therefore, they said that you need to train fast-twitch fibers and “don’t sweat it.” The research was closed.

But what was the surprise of the men in white coats when, after some time, they took samples of muscle tissue from professional bodybuilders! THE NUMBER OF FAST AND SLOW MUSCLE FIBERS WAS THE SAME!

After additional experiments, scientists concluded that SLOW MUSCLE FIBERS GROW AS WELL AS FAST FIBERS!

Why do bodybuilders' results differ from other athletes?

The difference is in the goals. In Olympic sports they are different. Run faster, push more, throw further, etc. And in bodybuilding, volumes, proportions and appearance are important.

Therefore, it is important for Olympians to minimize muscle growth, including IMM. They need fast or high-threshold muscle fibers in order to make maximum effort at the right moment.

Okay, you might say, why then don’t marathon runners, who need slow-twitch muscle fibers, have huge, toned legs? It's all about the MMV training method, friends.

Method of training MMV. Blood acidification

First, a little theory. With all the current technical and other progress, we still DO NOT KNOW WHAT EXACTLY TRIGGERS MUSCLE GROWTH!

But what about the progression of loads, stress, anabolic hormones, amino acids, etc., you ask? Yes, and again, yes! Only these are only the FINAL MECHANISMS OF MUSCLE GROWTH.

But we know for sure that NEW PROTEIN SYNTHESIS IS TRIGGERED THROUGH THE CELL'S DNA.

In order for hormones to trigger protein synthesis, this information must be copied from the DNA of the cell nucleus. And the DNA chain itself, as we know, is twisted from two helices.

To start protein synthesis YOU NEED TO UNLOCK THE DNA HELIDS! How to do it? With the help of HYDROGEN IONS!

Pumping– this is, roughly speaking, pumping blood into muscles. But remember what pumping should be like, in the classical sense? I won’t languish, he must be POWERFUL! Those. approximately 80% of WORKING WEIGHT!

For example, if you bench pressed a 100 kg barbell 6-8 times, then for a pumping workout you need to lift 80 kg and perform 12-15 repetitions. Do you understand? This will pump blood into the muscles, but this is not exactly the mode of operation that is aimed at developing IMM.

Add to this the fact that in pumping training, as a rule, the approach is performed at a FAST PACE! And for the fast pace of movement we have created BMWs.

MMB should be trained with approximately 50% weight and at a VERY SLOW pace! But more on that later.

Let's return to the question, why long-distance marathon runners don't have large slow-twitch muscle fibers? After all, they directly train them!

There are two factors here:

1. No load progression. Although the load is light and monotonous, it must grow, otherwise there will be no point in the muscles increasing.
2. No muscle acidification. Yes, they work for a long time, with a lot of repetitions (thousands of steps), but the BLOOD CIRCULATES FREELY IN THE MUSCLES (in and out), so it washes away the hydrogen ions. Accordingly, there is no growth reaction.

How to make MMV grow?

Although MMF grow no worse than BMW, in order for protein synthesis to start in muscle fiber (any muscle fiber, even MMF), the presence of HYDROGEN IONS is necessary, which trigger it.

It is easier for fast muscle fibers to achieve this, because. for energy supply they use the ANAEROBIC (oxygen-free) method. Therefore, the blood (the instrument for transporting oxygen to the muscles) DOES NOT WASH AWAY THE HYDROGEN IONS, which are needed to trigger muscle growth.

Why is this more difficult to do in MMV? Because MMVs use an AEROBIC (oxygen) method of energy supply! This means that blood is needed to transport oxygen. Do you understand? Blood makes it possible to feed on oxygen (deliver it), but WASHES AWAY HYDROGEN IONS, which are needed for growth! Here is a vicious circle that does not allow MMV to grow under normal conditions.

To put it simply, “native” methods of energy supply allow BMW to grow, but do not allow MIW to grow!!! This is why marathon runners have small muscles.

All this is understandable, but how to get out of this vicious circle and pump up our slow muscle fibers to become 2 times larger?

• Make MMV work;
• Use another method of energy supply;

Those. a certain load is needed to TURN ON the MMV, but NOT TO RELEASE BLOOD FROM THE MUSCLE in order to acidify it!!!

How to do it? PUMPING, friends! But in a slightly different mode.

Optimal pumping mode

In bodybuilding, a dynamic (fast) mode of performing the exercise is usually used, and relaxation follows after each repetition.

In this mode, the vessels unclench and allow blood to circulate freely into and out of the muscle. This is bad for the growth of IMM, because... they need HYDROGEN IONS to grow, and the blood washes them away. The muscle does not acidify and the muscle mass does not grow (there is no increase in strength and mass).

Therefore, the classic pumping mode, i.e. DYNAMIC POWER IS NOT SUITABLE FOR US!

We need to use CONSTANT MUSCLE TENSION! After all, if a muscle is tense, it does not allow blood to pass through. This is good because... this contributes to the accumulation of HYDROGEN IONS in it!

HYPOXIA(no oxygen due to constant voltage) –> ANAEROBIC GLYCOLYSIS(breakdown of glucose without oxygen) –> Accumulation of HYDROGEN IONS.

Great. That's sorted out. Again. The muscle should not allow blood to pass through (constant tension), anaerobic glycolysis occurs (no air), so hydrogen ions accumulate (since blood and oxygen do not circulate).

Now let's look at what conditions should be for MMV hypertrophy.

Practical scheme for MMV hypertrophy

What we need for maximum hypertrophy (“swelling” of muscle cells):

Let's look at this using the example of a standing biceps curl.

For example, your working weight is 30 kg for 10-12 reps, and you lifted 40 kg for 1 rep (40 kg is your 1 rep max). PM is a repeated maximum!

How to proceed?

• First we select the weight based on our 1RM. We take 30-50% of it, i.e. from 40 kg, it will be 12-20 kg.
• Now, by bending our elbows, we remember our starting position. THE HANDS SHOULD NOT BE COMPLETELY EXTENSION during the approach to avoid bleeding. We work INSIDE the amplitude! Those. we do not reach the top and bottom points. As soon as we feel that the muscle can relax, we stop and move in the opposite direction.
• Raise and lower the barbell VERY SLOWLY! On the count of 1-2 up and 3-4 down! If possible, even slower! This is how we use our MMVs and turn off the BMWs from operation.
• WE ACHIEVE AN UNBEARABLE BURNING! This is a very important point. It must be so strong that lifting this lightest weight again is simply not possible. We reach muscle failure. This will indicate extreme acidification of the muscle, i.e. about the high content of HYDROGEN IONS. There will be more repetitions than usual, namely 20-30 and the approach will last 30-50 seconds. This is fine!

This is what one approach would look like. How many approaches should there be? In theory, A LOT, but we, as you know, , so let's look for a solution.

To reduce the burning sensation we need about 5 minutes, and for it to disappear completely we need 40-60 minutes.

Therefore, based on the above, it would be optimal to perform such approaches every hour throughout the day. But this will be convenient for few people.

I prefer to use the STEP METHOD of muscle acidification. Those. you perform 3-4 approaches with MINIMUM REST, then rest for 3-4 minutes and again repeat 3-4 approaches, so again rest 3-4 minutes and again the series.

Example: You completed a biceps curl in 30 seconds. Rest for 20-30 seconds and repeat the second set, now rest again for 20-30 seconds and perform the third set. Now rest for 3-4, or maybe 5 minutes. And repeat a series of 3 approaches with a break of 20-30 seconds. Such “series” can be done from 2 to 5 within one workout.

AN APPROACH(30-50 sec) + REST(20-30 sec) + AN APPROACH(30-50 sec) + REST(20-30 sec) + AN APPROACH(30-50 sec) + REST (3-5 minutes!) … REPEAT SERIES…

By the way, this is convenient because many exercises can be performed at home (push-ups, biceps, triceps, deltoids).

Conditions for muscle growth

So, what does it take to grow muscles?

• TRAINING STRESS (destruction)! It is needed to promote the production of ANABOLIC HORMONES! Only then will the body turn on the growth process (anabolism).
• HORMONAL BACKGROUND! We need HORMONES that copy information about protein synthesis from the cell's DNA. It is thanks to them that metabolism (metabolism) shifts towards growth (anabolism). The destruction of protein structures during training forces the body to repair the damage. This healing is precisely called PROTEIN SYNTHESIS.
• HYDROGEN IONS! We have already talked about them quite a lot today. They UNCOIL the DNA helix so that information about protein synthesis becomes available for reading by hormones (steroid-receptor complexes). If there are not enough hydrogen ions released in response to ATP consumption, then hormones will not be able to read information about protein synthesis and trigger growth. REMEMBER: HORMONES (steroids) without training stress WILL NOT GIVE RESULTS, but TRAINING WITHOUT HORMONES WILL!
• CREATINE PHOSPHATE! Gives energy to the DNA molecule for fast work. Also, supplementing with CREATINE MONOHYDRATE can help you complete an extra couple of reps in your workout. A good thing.
• AMINO ACIDS for growth! In order to grow muscles, you need something to grow from! Amino acids are plastic building materials for muscle growth.

Yes, protein (amino acids) is very important! But more in conditions of DIET (deficiency of simple carbohydrates). Imagine when you are losing weight, i.e. If you don’t eat carbohydrates and exercise, then there is VERY LITTLE glycogen in your muscles, which means you have to use amino acids as energy (an expensive source of nutrition). If you drink extra during training and after amino acids, you will retain more muscle.

This is not beneficial for sports nutrition manufacturers, because... PROTEIN IS MORE EXPENSIVE and you can get MORE from its sale! But I believe that it is so. CARBOHYDRATES ARE MORE IMPORTANT than protein, especially when gaining muscle mass, because... give energy to your muscles.

The fact is that after training, your body DOESN'T EVEN THINK about growing muscles, because... it has depleted its energy reserves! He needs to make up for them! That is why for the next two days after training, your body replenishes energy reserves and does not even think about growth. And contractile proteins continue to be destroyed due to enzymes - PROTEIN KINASES! Only after 2 days the body starts recovery and, as is usually written, it recovers in 7 days. But in fact, even more. Usually within 10-14 days.

Let's summarize:

1. TRAINING STRESS(destruction).
2. HORMONAL BACKGROUND(starting synthesis from DNA).
3. HYDROGEN IONS(unwinding of the DNA helix for hormones).
4. CREATINE PHOSPHATE + CARBOHYDRATES(energy supply).
5. AMINO ACIDS(building material for plastic structures).

This applies to ANY muscle fibers (MMV, BMW, VBMV). The only difference is that for MMV it is more difficult to maintain the desired concentration of hydrogen ions, so it is necessary to perform the exercises in a certain way, as we discussed earlier in this article.

Is it possible to combine MMV and BMW training?

Can. I'll tell you more. That's exactly what I did in the army. I remember that I once trained my arms so much that I couldn’t button up my jacket in the morning; my colleagues helped me, because... they were unbearably sick! That's what it means, I've never trained MMV.

There are several basic rules:

• WE ALWAYS TRAIN AFTER BMW(if you train them in the same workout).
• MMV RECOVER SMALLER(2-3 days, i.e. already on the third day you can train again).
• BMW + 1-2 days of rest + MMV(if you train in different workouts).

Example of training program No. 1 (ALTERNATING WEEKS):

• BMW week (80-90% of 1 RM, 6-8 reps, fast pace, failure);
• week IMM (30-50% of 1 RM, 30-50 sec approach, constant tension, failure);
• Recovery week (50%, 8-12 reps, no failure);

Example of training program No. 2 (BMW + MMV in one training session):

• BMW Week + MMV;
• Recovery week (or very light training with 50% weight NOT TO FAILURE);

OK. But how can we combine MMV and BMW training in practice?

Example of a combination (BMW + MMV in one training session):

1. BMW– Incline bench press: 4 sets (80 kg x 6-12).
2. BMW– Incline dumbbell press: 4 sets (30 kg (1 dumbbell) x 6-12).
3. BMW– Dumbbell flyes lying on a bench: 4 sets (20 kg (1 dumbbell) x 8-12).
4. MMB – Incline Bench Press: 2-3 x ((30 kg = 30-50 sec. approach + 20-30 sec. rest) x 3 sets + rest 3-5 minutes + REPEAT SERIES...).
5. MMV– Incline Dumbbell Press: 2-3 x ((10-15 kg (1 dumbbell) = 30-50 sec. approach + 20-30 sec. rest) x 3 sets + rest 3-5 minutes + REPEAT SERIES...).

Do you see what's funny? We always download BMW at the beginning, before MMV! MMV IS ALWAYS IN THE END! UNDER NO EVENT CAN YOU CHANGE PLACES!

If we trained two muscle groups in one workout, for example, CHEST + ARMS, then we would first need to train the BMW CHEST, then the BMW ARMs, and only THEN the MIB CHEST + MIB ARMs. Just as you can see, WE TRAIN THE LARGE MUSCLE GROUPS FIRST (legs, back, chest), and only then the SMALL MUSCLE GROUPS (delts, arms, calves).

RIGHT= BMW Chest + BMW Arms + MMV Chest + MMV Arms.

WRONG = BMW Chest + MMV Chest + BMW Arms + MMV Arms.

WRONG= BMW Arms + BMW Arms + BMW Chest + BMW Chest.

I guess I’ll end this article here. If you are a beginner, then you DO NOT NEED this for now, but if you are already an experienced athlete who has been training for two years and has stagnated in results, then IMM training can be a very good help in achieving new horizons in muscle growth.

P.S. Subscribe to blog updates. It will only get worse.

With respect and best wishes,!

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 the practical side of the issue, 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 to work 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. An ideal endurance workout 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 do more aerobic training per week, 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 the aerobic heart rate zone are aimed at burning fat and recruiting 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 fiber 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:

1. choose 1 insulating (conditional isolation) exercise for a specific muscle group, for example, biceps - lifting a dumbbell with one hand / EZ-bar with two;
2. select the weight of the projectile so that you can perform “cleanly” independently only 1 repetition ( 1 RM);
3. rest 3-5 minutes;
4. 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.
5. 4 before 7 , then you have predominantly fast (glycolytic) muscle fibers that are strong but not durable;
6. if the number of repetitions is 10 , then there is parity of fast and slow fibers;
7. 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 we are talking about. For example, you need to determine which fibers predominate in your biceps brachii muscle. you were able to raise 1 times dumbbell for biceps 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 – pull the upper block to the chest while sitting;
• shoulders – ;
• front surface of the thigh – leg extensions in the simulator;
• back of the thigh – .

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 compiled a kind of generalized atlas of 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 knee extensions in a sitting machine, (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 the gym often to train fast-twitch 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 weights. 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 muscle fiber type. That is why these representatives slowly gain muscle mass, because... their fibers inhibit and there are many of them. With 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 fast-twitch 2B fibers. When doing 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 for 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.

Many scientific studies 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 a strength workout (lifting) and consist of exercises - deadlifts, 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 for now, I was glad to fall asleep writing for you, see you later!

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.

Skeletal muscle fibers are divided into fast and slow. The speed of muscle contraction varies and depends on their function. For example, the calf muscle contracts quickly, and the eye muscle contracts even faster.

Rice. Types of muscle fibers

IN fast muscle fibers the sarcoplasmic reticulum is more developed, which contributes to the rapid release of calcium ions. They are called white muscle fibers.

Slow muscles are constructed from smaller fibers and are called red fibers because of their reddish color due to their high myoglobin content.

Rice. Fast and slow muscle fibers

Table. Characteristics of three types of skeletal muscle fibers

Index	Slow oxidative fibers	Fast oxidative fibers	Fast Glycolytic Fibers
The main source of ATP formation		Oxidative phosphorylation	Glycolysis
Mitochondria
Capillaries
	High (red muscles)	High (red muscles)	Low (white muscles)
Glycolytic enzyme activity		Intermediate
		Intermediate
Fatigue rate	Slow	Intermediate
Myosin ATPase activity
Shortening speed	Slow
Fiber diameter
Motor unit size
Motor axon diameter

Muscle strength

The strength of a muscle is determined by the maximum amount of load it can lift, or by the maximum force (tension) it can develop under isometric conditions.

Single muscle fiber capable of developing a force of 100-200 mg. There are approximately 15-30 million fibers in the body. If they acted in parallel in the same direction and at the same time, they could create a voltage of 20-30 tons.

Muscle strength depends on a number of morphofunctional, physiological and physical factors.

Calculation of muscle strength

Muscle strength increases with increasing area of ​​their geometric and physiological cross-section. The physiological cross-section of a muscle is the sum of the cross-sections of all muscle fibers along a line drawn perpendicular to the course of the muscle fibers.

In a muscle with parallel fibers (for example, the sartorius muscle), the geometric and physiological cross-sectional areas are equal. In muscles with oblique fibers (intercostal) the physiological cross-sectional area is larger than the geometric area and this helps to increase muscle strength. The physiological cross-section and strength of muscles with a feathery arrangement of muscle fibers, which is observed in most muscles of the body, increase even more.

In order to be able to compare the strength of muscle fibers in muscles with different histological structures, the concept of absolute muscle strength is used.

Absolute muscle strength- the maximum force developed by the muscle, calculated per 1 cm 2 of physiological cross-section. The absolute strength of the biceps is 11.9 kg/cm2, the triceps brachii muscle is 16.8, the gastrocnemius muscle is 5.9, and the smooth muscle strength is 1 kg/cm2.

where A ms is muscle strength (kg/cm2); P is the maximum load that the muscle can lift (kg); S is the physiological cross-sectional area of ​​the muscle (cm2).

Strength and speed of contraction, muscle fatigue depends on the percentage of different types of motor units included in that muscle. The ratio of different types of motor units in the same muscle varies from person to person.

The following types of motor units are distinguished:

• slow, non-fatiguing (red), they develop a small force of contraction, but can remain in a state of tonic tension for a long time without signs of fatigue;
• fast, easily fatigued (white in color), their fibers develop great contraction force;
• fast, relatively resistant to fatigue, developing a relatively large force of contraction.

In different people, the ratio of the number of slow and fast motor units in the same muscle is determined genetically and can vary significantly. The greater the percentage of slow fibers in a person’s muscles, the more adapted it is to long-term, but low-power work. Individuals with a high content of fast, strong motor units in their muscles are able to develop greater strength, but are prone to fatigue quickly. However, we must keep in mind that fatigue depends on many other factors.

Muscle strength increases with moderate stretching. One explanation for this property of muscle is that when the sarcomere is stretched moderately (up to 2.2 μm), the likelihood of more connections between actin and myosin increases.

Rice. Relationship between contractile force and sarcomere length

Rice. The relationship between muscle strength and its length

Muscle strength depends on the frequency of nerve impulses, sent to the muscle, synchronizing the contraction of a large number of motor units, preferentially involving one or another type of motor units in the contraction.

The strength of contractions increases:

• when more motor units are involved in the contraction process;
• when synchronizing the contraction of motor units;
• when more white motor units are involved in the contraction process.

If it is necessary to develop a small force, slow, non-fatiguing motor units are activated first, then fast, fatigue-resistant ones. If it is necessary to develop a force of more than 20-25% of the maximum, then fast, easily fatigued motor units are involved in the contraction.

At a voltage of up to 75% of the maximum possible, almost all motor units are activated and a further increase in strength occurs due to an increase in the frequency of impulses sent to the muscle fibers.

With weak contractions, the frequency of sending nerve impulses along the axons of motor neurons is 5-10 impulses/s, and with a strong contraction force it can reach up to 50 impulses/s.

In childhood, strength increases mainly due to an increase in the thickness of muscle fibers, which is associated with an increase in the number of myofibrils in them. The increase in the number of fibers is insignificant.

When training muscles in adults, an increase in their strength is associated with an increase in myofibrils, and an increase in their endurance is due to an increase in the number of mitochondria and the production of ATP due to aerobic processes.

There is a relationship between the strength and speed of muscle contraction. The greater the length of a muscle, the greater the speed of muscle contraction (due to the summation of the contractile effects of sarcomeres). It decreases with increasing load. A heavy load can only be lifted by moving slowly. The maximum contraction speed achieved during human muscle contraction is about 8 m/s.

Muscle power is equal to the product of muscle force and the rate of shortening. Maximum power is achieved at an average speed of muscle shortening. For the arm muscles, maximum power (200 W) is achieved at a contraction speed of 2.5 m/s.

The force of contraction and muscle power decrease as fatigue develops.

When training to burn fat or gain mass, you need to use different types of 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 programs for gaining muscle mass are designed to work specifically 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 of the body are made up of different types of 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.