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Forms of muscle contraction (isotonic, isometric, mixed). Modes of contraction and types of muscle work

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In resting muscle fibers, in the absence of motor neuron firing, transverse myosin bridges are not attached to actin myofilaments. Tropomyosin is located in such a way that it blocks actin sites that can interact with myosin cross-bridges. Troponin inhibits myosin - ATP-ase activity and therefore ATP is not split. Muscle fibers are in a relaxed state.

When the muscle contracts, the length of the A-disks does not change, the J-disks shorten, and the H-zone of the A-disks may disappear (Fig. 4.3.).

Fig.4.3. Muscle contraction. A - Cross bridges between actin and myosin are open. The muscle is in a relaxed state.
B - Closing of transverse bridges between actin and myosin. Commitment by the heads of the bridges of rowing movements towards the center of the sarcomere. Sliding of actin filaments along myosin filaments, shortening of the sarcomere, development of traction.

These data were the basis for the creation of a theory explaining muscle contraction by the sliding mechanism. (slip theory) thin actin myofilaments along thick myosin. As a result, myosin myofilaments are drawn between the surrounding actin myofilaments. This leads to a shortening of each sarcomere, and hence the entire muscle fiber.

Molecular mechanism of contraction muscle fiber consists in the fact that the action potential arising in the area of ​​the end plate propagates through the system of transverse tubules deep into the fiber, causes depolarization of the membranes of the sarcoplasmic reticulum cisterns and the release of calcium ions from them. Free calcium ions in the interfibrillar space trigger the contraction process. The set of processes that cause the propagation of the action potential deep into the muscle fiber, the release of calcium ions from the sarcoplasmic reticulum, the interaction of contractile proteins and the shortening of the muscle fiber are called "electromechanical interface". The time sequence between the appearance of the action potential of the muscle fiber, the flow of calcium ions to the myofibrils and the development of fiber contraction is shown in Figure 4.4.

Fig.4.4. Development timeline diagram
action potential (AP), release of calcium ions (Ca2+) and development of isometric muscle contraction.

When the concentration of Ca 2+ ions in the intermyofibrillar space is below 10″, tropomyosin is located in such a way that it blocks the attachment of transverse myosin bridges to actin filaments. The cross bridges of myosin do not interact with actin filaments. There is no movement of actin and myosin filaments relative to each other. Therefore, the muscle fiber is in a relaxed state. When the fiber is excited, Ca 2+ leaves the cisterns of the sarcoplasmic reticulum and, consequently, its concentration near the myofibrils increases. Under the influence of activating Ca 2+ ions, the troponin molecule changes its shape in such a way that it pushes tropomyosin into the groove between two actin filaments, thereby freeing up sites for attaching myosin cross-bridges to actin. As a result, cross bridges attach to actin filaments. Since the myosin heads make "stroke" movements towards the center of the sarcomere, actin myofilaments are "pulled" into the gaps between the thick myosin filaments and the muscle is shortened.

Energy source for muscle contraction

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Energy source for contraction muscle fibers serves as ATP. With the inactivation of troponin by calcium ions, the catalytic sites for the breakdown of ATP on the myosin heads are activated. The enzyme myosin ATPase hydrolyzes the ATP located on the head of the myosin, which provides energy for the cross bridges. The ADP molecule and inorganic phosphate released during ATP hydrolysis are used for the subsequent resynthesis of ATP. A new ATP molecule is formed on the myosin cross bridge. In this case, the transverse bridge is disconnected from the actin filament. Reattachment and detachment of the bridges continues until the calcium concentration within the myofibrils decreases to a subthreshold value. Then the muscle fibers begin to relax.

With a single movement of the transverse bridges along the actin filaments (stroke movements), the sarcomere is shortened by approximately 1% of its length. Therefore, for a complete isotonic contraction of the muscle, it is necessary to perform about 50 such rowing movements. Only the rhythmic attachment and detachment of the myosin heads can draw the actin filaments along the myosin filaments and accomplish the required shortening of the whole muscle. The tension developed by the muscle fiber depends on the number of simultaneously closed transverse bridges. The rate of development of tension or shortening of the fiber is determined by the frequency of closing of the transverse bridges formed per unit time, that is, the rate of their attachment to actin myofilaments. With an increase in the speed of muscle shortening, the number of simultaneously attached transverse bridges at each moment of time decreases. This can explain the decrease in the force of muscle contraction with an increase in the speed of its shortening.

With a single contraction, the process of shortening the muscle fiber ends after 15-50 ms, since the calcium ions that activate it return to the cisterns of the sarcoplasmic reticulum with the help of a calcium pump. Muscle relaxation occurs.

Since the return of calcium ions to the cisterns of the sarcoplasmic reticulum goes against the diffusion gradient, this process requires energy. Its source is ATP. One ATP molecule is spent on the return of 2 calcium ions from the interfibrillar space to the cisterns. With a decrease in the content of calcium ions to a subthreshold level (below 10 V), troponin molecules take on a shape characteristic of the resting state. At the same time, tropomyosin again blocks the sites for attaching transverse bridges to actin filaments. All this leads to relaxation of the muscle until the next flow of nerve impulses arrives, when the process described above is repeated. Thus, calcium in muscle fibers plays the role of an intracellular mediator linking the processes of excitation and contraction.

Modes and types of muscle contractions

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3.1. Single cut

The mode of contraction of muscle fibers is determined by the frequency of impulses of motor neurons. The mechanical response of a muscle fiber or individual muscle to a single stimulation of them is calledsingle contraction .

With a single reduction, they distinguish:

1. The phase of stress development or shortening;

2. The phase of relaxation or lengthening (Fig. 4.5.).

Fig.4.5. Time development of the action potential (A) and isometric contraction of the adductor muscle thumb brushes (B).
1 - phase of voltage development; 2 - relaxation phase.

The relaxation phase lasts about twice as long as the tension phase. The duration of these phases depends on the morphological and functional properties of the muscle fiber: in the most rapidly contracting fibers of the eye muscles, the tension phase is 7–10 ms, and in the slowest fibers of the soleus muscle, it is 50–100 ms.

Under natural conditions, the muscle fibers of the motor unit and the skeletal muscle as a whole work in a single contraction mode only when the duration of the interval between successive motor neuron impulses is equal to or exceeds the duration of a single contraction of the muscle fibers innervated by it. Thus, the mode of single contraction of slow fibers of the human soleus muscle is provided at a motor neuron impulse frequency of less than 10 imp/s, and fast fibers of the oculomotor muscles - at a motoneuron impulse frequency of less than 50 imp/s.

In the mode of a single contraction, the muscle is able to work for a long time without developing fatigue. However, due to the fact that the duration of a single contraction is short, the tension developed by the muscle fibers does not reach the maximum possible values. With relatively high frequency impulsation of motoneurons, each subsequent irritating impulse falls on the phase of the previous fiber tension, that is, until the moment when it begins to relax. In this case, the mechanical effects of each previous contraction are summed up with the next one. Moreover, the magnitude of the mechanical response to each subsequent pulse is less than the previous one. After the first few impulses, subsequent responses of muscle fibers do not change the tension achieved, but only maintain it. This reduction mode is calledsmooth tetanus (Fig.4.6.). In this mode, the motor units of human muscles work with the development of maximum isometric efforts. With smooth tetanus, the tension developed by DE is 2-4 times greater than with single contractions.

Fig.4.6. Single (a) and tetanic (b, c, d, e) contractions of the skeletal muscle. Superimposition of contraction waves on each other and the formation of tetanus at stimulation frequencies: 5-15 times / s; c — 20 times/s; d — 25 times/s; e - more than 40 times in 1 second (smooth tetanus).

In cases where the intervals between successive impulses of a motor neuron are less than the time of a complete cycle of a single contraction, but more than the duration of the tension phase, the force of contraction DE fluctuates. This reduction mode is called tooth chat tetanus (Fig. 4.6.).

Smooth tetanus for fast and slow mice is achieved at different frequencies of motoneuron firing. It depends on the time of a single contraction. Thus, smooth tetanus for the fast oculomotor muscle appears at frequencies above 150–200 pulses/s, and for the slow soleus muscle, at a frequency of about 30 pulses/s. In the mode of tetanic contraction, the muscle is able to work only a short time. This is explained by the fact that due to the lack of a relaxation period, she cannot restore her energy potential and works as if “in debt”.

Mechanical reaction of the whole muscle when it is excited

The mechanical reaction of the whole muscle during its excitation is expressed in two forms - in the development of tension and in shortening. Under natural conditions of activity in the human body, the degree of muscle shortening can be different.

By size shortening There are three types of muscle contraction:

1. Isotonic- this is a contraction of the muscle, in which its fibers are shortened with a constant external load. In real movements, a purely isotonic contraction is practically absent;

2. Isometric is a type of muscle activation in which it develops tension without changing its length. Isometric contraction is at the heart of static work;

3. Auxotonic or anisotonic type- this is the mode in which the muscle develops tension and shortens. It is these contractions that take place in the body during natural locomotion - walking, running, etc.

3.2. Dynamic reduction

Isotonic and anisotonic types of contraction underlie dynamic work human locomotor apparatus.

In dynamic work, there are:

1. Concentric type of contraction- when the external load is less than the tension developed by the muscle. At the same time, it shortens and causes movement;

2. Eccentric type of contraction- when the external load is greater than the muscle tension. Under these conditions, the muscle, tensing, nevertheless stretches (lengthens), while performing negative (inferior) dynamic work

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One of the classic power training techniques is to try to move the weight as fast and as fast as possible. the greatest force throughout the entire movement. Thus, good means power development is the use of free weights and other equipment that allows you to quickly move the weight. The weight of the equipment used for isotonic (Methodology) represents external resistance. The force required to overcome the inertia of the barbell or to move it is called the applied force, and the more the applied force exceeds the external resistance, the faster the weight moves.

If a novice athlete applies a force equal to 95 percent of a rep max to lift a barbell that is equal to the amount of one rep max, the athlete will not be able to generate acceleration. However, if the same athlete works on developing maximum strength for one to two years, his strength will increase so much that lifting the specified weight will represent a load equal to only 40-50 percent of the repetition maximum. In this situation, the athlete will be able to lift the bar in an explosive manner and generate the acceleration needed to increase power. This difference explains the need for the periodization of strength development to include the stage of maximum strength before the stage of power training. Without an increase in maximum strength, there can be no visible increase in power.

A high level of maximum strength is also required for early stage perform a lift or throw. Any barbell or sports equipment (for example, a ball) has a certain inertia, which is expressed in mass. The most difficult stage of the explosive lifting of the barbell or throwing the projectile is initial stage. To overcome inertia, the athlete must provide a certain level of tension in the corresponding muscles. Therefore, the greater the maximum strength of the athlete, the easier it is for him to overcome inertia, and the more explosive the initial stage of the movement will be. As the athlete continues to apply force to the bar or apparatus, he increases the speed of the movement of the bar or apparatus. The greater the speed becomes, the less force is required to maintain it.

The continuous increase in speed means that the speed of the limb also increases. This increase is only possible if the athlete can perform rapid contraction Muscle: A skill for which athletes involved in speed/strength sports rely on power training during the conversion phase. Without power training, an athlete will never be able to jump higher, run faster, throw farther, or land a quick punch. In order to improve the performance of this skill, the athlete needs more than just maximum strength. The athlete must be able to exert maximum strength at very high speed, and this skill can only be developed through the use of power training techniques.

At the stage of development of maximum strength, the athlete gets used to high loads. Thus, the use of loads in the range from 30 to 80 percent of the repeated maximum helps the athlete to develop specific power and at the same time the high level of acceleration necessary for the manifestation of power.

For most sports that involve cyclic movement (eg, sprinting, team sports, and martial arts), the isotonic approach should require a load of 30 percent or more (up to 50 percent). For sports with an acyclic nature of movement (for example, throwing disciplines, weightlifting, or American football offensive play), loads can be higher and range from 50 to 80 percent, due to the much greater mass and initial maximum strength of these athletes, and also the need to overcome an increased level of external resistance. In fact, the increase in power is a very specific aspect if we are talking about the angular velocity and the load, therefore, it is necessary to choose the load in accordance with the amount of external resistance that must be overcome. The training parameters are shown in Table 1.

As the joint is fully extended, nervous system will naturally activate the antagonist muscles to slow down the movement. At the same time, from a biomechanical point of view, the exercise becomes more beneficial when the joint "opens up" (less force is required). For this reason, it is recommended to use smoothing resistance in the form of tapes or chains when operating at low loads (30 to 50 percent). Studies have shown that the use of a smoothing resistor leads to a greater increase in power when working with small loads.

It should be remembered that when using tapes, in particular in substantial degree is involved central system, which means the need right choice the duration of breaks between sets and the frequency of use of the specified type of training. In addition, since the key element of power training is not the number of repetitions performed, but the ability to quickly activate the maximum number of fast-twitch fibers, the authors suggest using a small number of repetitions (from one to eight).

Athletes should also keep safety in mind. When extending the limb, unnecessary movements should be avoided. In other words, the exercises should be performed in an explosive manner, but without jerking the barbell or sports equipment. We repeat, most important element is an impeccable technique.

Table 1. Training parameters for the isotonic technique

Stage duration:	3-6 weeks
Cyclic: 30-50% remax Acyclic: 50-80% remax
Number of exercises
Number of repetitions per approach	Cycling: 5-8 reps at 30^40% rep max, 3-6 reps at 40-50% rep max Acyclic loading: 5 or 6 reps under load at 50-70% rep max, 1-5 reps under load at 70-80% rep max
The number of approaches in the exercise
Rest break	Cyclic: 1-2 min. at 30-40% of a repeated maximum, 2-3 min. at 40-50% remax Acyclic: 2-4 min.
Execution speed	Explosive
Frequency of training per week:

* Smaller figure - for more exercises and vice versa.

To perform powerful sporting actions, such as throwing, jumping, diving, cricketing, batting, batting, and American football offensive play, in an explosive, acyclic manner, repetitions must be performed with some rest time, for through which the athlete can concentrate as much as possible to ensure optimal movement dynamics. This strategy also activates fast twitch motor units and increases energy production. The athlete can perform one rep at a time, provided it is done in an explosive manner to ensure maximum recruitment of fast twitch muscle fibers and increase the rate of activation.

When an athlete can no longer perform a rep in an explosive manner, he should stop, even if the set has not been completed completely. By continuing to perform reps without explosive movements, strength endurance is being trained, not power. Maximum engagement and high speed activation of fast-twitch fibers occurs only in the case of a combination of maximum concentration and explosive actions, and the achievement high level of these elements is possible only if the athlete is not under the influence of fatigue.

It doesn't matter if it's working on developing power or strength endurance, but during the rest break, the athlete must relax the muscles involved. When relaxing during a rest break, ATP resynthesis is enhanced, due to which the required amount of energy sources enters the muscles. This recommendation does not mean that the athlete should stretch the muscles used, because in this situation, energy production will decrease during the next set. Thus, stretching of the agonist muscles should not be performed between sets.

For power training, very specific exercises should be selected, during which the kinetic chain used in a particular sport is reproduced. From this point of view, it is obvious that the bench press and power clean will not give amazing results, despite the fact that these exercises are traditional for power training. Power lifting is useful for throwers and linebackers in American football, but is not required, for example, for football players or racquet sports players. For these athletes, jump squats and heavy kettlebell swings are better suited. per training session up to eighteen) and optimal benefits for the main moving muscles. When determining the number of sets and exercises, coaches should remember that power training is performed in combination with training in technical-tactical skills. Thus, only a certain amount of energy is allocated for the implementation of this workout.

A key element in power development when using the isotonic technique is the speed at which force is exerted. For maximum power growth, the force application rate should be as high as possible. The rapid application of force against an implement or weight over a range of motion is vital. important aspect and should start at the earliest stage of the movement. The athlete must be as focused as possible on the task in order to move the barbell or sports equipment quickly and dynamically.

Figure 1 shows an example of a power training program for a college basketball player who has four years of strength training under her belt. The maximum level of mechanical energy production is usually achieved at a load equal to 50 percent of the repetition maximum (plus or minus 5 percent) during a strength exercise and about 85 percent for Olympic combined. Power loss occurs around the sixth rep of each set.

muscle contraction at a constant tension, expressed in a decrease in its length and an increase in its cross section. In the body And. m. V pure form not visible. To purely I. m. the movement of an unloaded limb approaches; with a gradual increase in the load until it can no longer be lifted, it is possible to observe all the transitions from I. m. to isometric muscle contraction (See Isometric Muscle Contraction).

• - a complex of sensations arising from work muscular system body...

  Great Psychological Encyclopedia

• - a complex receptor organ in the skeletal muscles of terrestrial vertebrates. It plays an important role in the organization of movements, enters the system of proprioceptors, participates in the formation of muscle sensation. . ...
• - shortening or tension of the muscles in response to irritation caused by the discharge of the motor. neurons...

  Biological encyclopedic dictionary

• - sensations arising from irritation of the sensitive structures of the musculoskeletal system ...

  Biological encyclopedic dictionary

• - common name V., which are components of muscle tissue ...

  Big Medical Dictionary

• - muscular V., which is part of the neuromuscular spindle; peripheral parts of V. of m. have transverse striation and are capable of contraction, the central part does not contract ...

  Big Medical Dictionary

• - see Nervous-...

  Big Medical Dictionary

• - see Abbreviation...

  Big Medical Dictionary

• - S., in which muscle fibers shorten and thicken, and their tension practically does not change ...

  Big Medical Dictionary

• - shortening or change in the tension of the muscle fibers that make up the muscle ...

  Big Medical Dictionary

• - U., manifested mainly in a certain group of muscles that were subjected to the greatest stress during work ...

  Big Medical Dictionary

• - see Kinesthesia...

  Big Medical Dictionary

• - a sensation that occurs in the depths of our members and mainly in the muscles, their tendons, in the articular bags and ligaments, and even in the articular parts of the bones, and reaching from there to the centers of the brain in special ...

  encyclopedic Dictionary Brockhaus and Euphron

• - muscle contraction, expressed in an increase in its tension with a constant length ...
• - shortening of the muscle, as a result of which it produces mechanical work. M. s. provides the ability of animals and humans to voluntary movements ...

  Great Soviet Encyclopedia

• - muscular-articular reception, proprioception, the ability of humans and animals to perceive and evaluate changes in the relative position of body parts and their movement ...

  Great Soviet Encyclopedia

"Isotonic Muscle Contraction" in books

Priority Reduction

From the book Pushkin's volume [collection] the author Bitov Andrey

Reducing the priority of Lyubonachalia, this hidden snake ... Pushkin, 1836 your text with feeling,

What does the abbreviation "pom" mean?

From the book The Book of General Delusions author Fry Stephen

What does the abbreviation "pom" mean? a) Port of Melbourne. b) Prisoners of Her Majesty. c) Prisoner of Old Mother England. d) Permit of Migration. e) Pomegranate ). Most of the list can be easily discarded,

16 REDUCTION

From the book Cocaine Kings author Gugliotta Guy

16 REDUCTION OF STAFF Lewis Thames and Johnny Phelps fulfilled their main mission: the agreement on the extradition of criminals was signed. They won. Tamz called 1984 a "breakthrough" year. Even the more cautious and skeptical Phelps ended up pleased with Betancourt. What

Subtlety of touch and muscle feeling

From the book Classic Russian Massage in 15 Days author Oguy Viktor Olegovich

The subtlety of touch and muscular sense The subtlety of touch and the degree of development of the muscular sense of the massage therapist play a paramount role in his work. The hand for the massage therapist is his second pair of eyes. And the muscular feeling and the subtlety of touch are significantly weakened by fatigue.

Prolonged muscle tension

From the book Complete Medical Diagnostic Handbook author Vyatkina P.

Prolonged muscle tension Symptoms. With so-called tension headaches, people experience a relatively constant feeling of heaviness in the back of the head and forehead, aggravated to a sensation of pain during prolonged fixation of the head (for example, while reading, writing),

Isometric muscle contraction

TSB

Isotonic muscle contraction

From the book Great Soviet Encyclopedia (FROM) of the author TSB

muscle contraction

TSB

muscle feeling

From the book Great Soviet Encyclopedia (WE) of the author TSB

Uncontrolled muscle tension and its treatment

From the book Osteochondrosis author Dolzhenkov Andrey Viktorovich

Uncontrollable muscle tension and its treatment physical exercise without breaks to stretch the overworked rectifier muscles of the spine, they eventually lead to their uncontrollable residual tension. The disc is constantly compressed

1. Muscle tension

From the book Guide to Systemic Behavioral Psychotherapy author Kurpatov Andrey Vladimirovich

1. Muscle tension A. Mental mechanismReduced general formula stress can be successfully applied to a particular case (element) of the body's stress response, namely, to the phenomenon of muscle tension.G. Selye identified two types of stress responses.

Muscle relaxation

author Lagutina Tatiana

Muscle Relaxation Below we will discuss the technique of progressive muscle relaxation. The techniques described are absolutely reliable, do not cause stress and do not require much physical effort. Exercises are aimed only at the muscles of the hands, forearms, legs and face.

Muscle relaxation with visualization

From the book How to improve memory and develop attention in 4 weeks author Lagutina Tatiana

Muscle Relaxation with Yoga Visualization used this exercise to achieve complete relaxation body and soul. In addition, it can be used to control the degree of relaxation that you achieve during training. Starting position: lying on your back

CONSISTENT MUSCLE RELAXATION

author Lapp Daniel

CONSISTENT MUSCLE RELAXATION Do this exercise at home or somewhere in a closed room: when you want to relax, you need to find yourself a secluded corner where you can be alone so that you are not interrupted or disturbed. Purpose of this exercise

MUSCLE RELAXATION WITH VISUALIZATION (USING MENTAL PICTURES)

From the book Improving memory - at any age author Lapp Daniel

MUSCLE RELAXATION WITH VISUALIZATION (USING MENTAL PICTURES) This exercise is borrowed from yogis - as soon as the muscles relax, they resorted to it for the simultaneous complete relaxation of the body and soul. Therefore, it will be useful to master

At huge selection systems for training, it would seem difficult to surprise an experienced athlete with something new. But in fact, we want to remind you of one undeservedly forgotten training program, which is aimed not only at strengthening the muscles of the whole body, but also at educating fortitude. No, this is not yoga! This is the Isoton system, which was developed by the Russian scientist V.N. Seluyanov back in 1992 and was effectively used to train students at the institutes of physical education. Now you can use it at home for weight loss and health promotion.

The difference between the Isoton system and other loads

Scientists first long and painstakingly studied and analyzed various systems training: yoga, bodybuilding, aerobics, callanetics, as well as developments physiotherapy exercises. As a result, it turned out new system, which is aimed at improving the body by normalizing the immune and endocrine systems, the site agrees. She helps:

Improve performance. This can be achieved in a short period of two to three months, during which excess body fat is burned and muscle mass is increased.
. Use a small amount of time to achieve maximum effect. This factor in the conditions of its constant shortage is also quite important.

Therefore, by adhering to this program, you will eventually get the opportunity to:

Strengthen your health and maintain all body systems in normal working condition.
. Normalize the psychological and emotional situation;
. It is easy to get up in the morning and forget about the breakdown;
. Get a normal weight;
. Get an attractive body and feel good about it.

The main difference of this system is the static-dynamic mode of training, that is, all exercises are performed very smoothly and slowly with constant muscle retention in a state of tension. Training is considered effective when each exercise is performed to failure, i.e. to the point of being unable to overcome resistance.

However, paradoxically, this system does not cause subsequent muscle pain and promotes rapid recovery.

Features of training according to the "Isoton" system

As already mentioned, training occurs to a burning sensation in the muscles. The pace of execution is very slow, you need to act according to the 30/30 scheme. Those. 30 seconds for exercise and 30 seconds for rest. We use it three times for one exercise. If your training does not allow, you can reduce the load by doing 20/40.

When your level increases, you can use circuit training, i.e. perform exercises without rest, then a break of 1-2 minutes. Then repeat this circle 4 times.

Isoton training program for home

First, there is a study of large muscles, then we train smaller ones:

1. Half squats. In the starting position: feet shoulder-width apart, hands on the belt, legs slightly bent. Squat down slowly until your thighs are parallel to the floor, then slowly back up. You do not need to straighten your legs in the starting position, they should always be tense.

2. Lunges. Standing, we take a long step with the foot, hands on the belt - the starting position. We begin to slowly lower ourselves down until the knee almost touches the floor (but you don’t need to put it on the floor). Now we return back.

3. Raise the buttocks. Lie down on the floor. Bend your legs at the knees and place them near the buttocks, arms along the body. Raise the pelvis gradually, without jerking, until a straight line with the body. We return back, while we do not put the buttocks on the floor, we maintain tension.
4. Push-ups on your knees. We kneel, hands at a distance wider than shoulders. We begin slow push-ups to the floor. When returning, we do not fully unbend the arms, they must maintain tension.

5. Reverse push-ups. Use a stool or other support. We turn our backs to the support, rest with our palms, bend our legs slightly. We transfer the weight of the body to the palms and heels, hover above the floor. We start push-ups. We go down and rise back, do not straighten our arms to the end.

6. Twisting. Lying on the floor, legs bent, we lean on the foot. Hands on the chest in a cross. We raise the head and shoulder girdle at the same time, we lower ourselves back, but the shoulders and head remain suspended.
7. Reverse twists. Lying on your back, raise your bent legs to a 90-degree angle. The back and pelvis are pressed to the floor, then we raise the pelvis, while the legs tend to the chest, we return to the starting position. Watch the press, it is tense all the time.
8. Plank. Lie down on the floor. Rest on your arms and toes bent at the elbows. Raise your body and hold it for as long as possible. Maintain a completely level position.

As you can see, after carefully looking at the terminology from the title of the article, the concepts of "isometric" and "isotonic" have one thing. common beginning- "iso". "Iso" in Greek means "equal", "same". What are the same things we do when doing isometric and isotonic exercises? And here we come to the rescue again Greek language. "Metric" in Greek means "size". That is, isometric exercises suggest that the length of the muscle (size) does not change during their execution, remains the same. But "Tonic" from Greek is interpreted as "tension", "pressure". That is, isotonic exercises are exercises during which the same tension is created in the muscles. In fact, both isometric and isotonic exercises are strength exercises. Both of them can be performed with the help of simulators, a barbell, a barbell, dumbbells, a bodybar, a medicine ball, etc. sports gadgets. However fundamental difference between isometric and isotonic exercises is that the first ones are performed in statics, and the second ones - in dynamics, i.e. in motion.

To make it more clear, let's look at isometrics and isotonics in sports using specific exercises as an example. The simplest isometric exercise can be performed as follows: press one palm against the other. Put all your strength into this pressure. Do you feel the tension in your arm muscles? In fact, you do not make any movement or movement in space. You are in static, overcoming the resistance of the palms. You are only making an effort, trying to make a movement, but you are not going to perform it. This is the point of isometric exercises - trying to pull, push, bend. In this case, you can use any object that is able to provide our muscles with insurmountable resistance - a wall, a window sill, a handrail, a neck, a barbell, big weight on various simulators, etc. This effort to resist pressure lasts about 6-12 seconds. During isometric exercises, muscle contraction does not lead to a change in its length, but only causes tension in it. All the energy in this case is spent precisely on this voltage.

Isotonic exercise is everything strength exercises with the use of weighting agents that are associated with reciprocating movements: different kinds bench press, squats, deadlifts, etc. Such movements cause such muscle contraction, as a result of which their length changes. All energy from isotonic loads is spent on movement.

An inquisitive reader has probably already had a question - which of the considered types of power load is more effective: isometric or isotonic? And in what proportions should they be included in the training? In fact, isometric exercises are undeservedly forgotten, and the recommended strength training plans consist entirely of isotonic exercises. Meanwhile, isometry gives whole line undeniable benefits to your workout.
First, it saves time. In the process of performing isometric exercises, it takes only a few minutes for the muscles to start working. The duration of the isometric exercise is short and it does not cause much fatigue. Thanks to this, you can train more often. As a result, the effect of just a few minutes of isometrics can be equated to an hour of traditional isotonics!

Secondly, isometric exercises allow you to work out a separate muscle group in isolation.

Thirdly, isometry is ideal for people who experience certain difficulties when moving in space in the post-traumatic period, etc.

Fourthly, isometric exercises can be performed without attracting the attention of others (on the beach, in the office, in public transport, etc.)

Fifth, isometry is, in principle, less traumatic than isotonics.

However, isotonic exercises are more suitable for female strength training, because they are not able to quickly help increase muscle mass. In addition, isotonics have a beneficial effect on the cardiovascular system, supplying the muscles with blood more intensively. Also, isotonic exercises contribute to the development of coordination of movement and plasticity.

Thus, we can conclude that different exercises are important and different exercises are important. The ideal training plan should include both isometric and isotonic exercises. Moreover, the first ones are more suitable for male strength training. Agree that pulling and pushing loads is not a woman's business. But isotonic work with dumbbells or a neck is both more aesthetic and effective in the formation of a relief elastic body. However, along the way, remember that strength training unable to solve problems such as overweight and excessive body fat. So don't forget about the importance of cardio, interval and circuit training.

Model in the photo: Alena Kaplunova