2.muscles of the back - movement of the head, neck, spine, maintaining the vertical position of the body, movement of the scapula, movement of the upper and lower extremities;

3.abdominal muscles form the abdominal press, participate in bending and turning the body;

4. Respiratory muscles: external and internal intercostal, diaphragm.

The muscles of the trunk perform the function of breathing, support the body in an upright position, and participate in the work of the arms and legs.

III. Muscles of the Extremities:

Arm muscles allow a person to perform very complex and precise movements. The muscles of the upper extremities provide labor activity.

Leg muscles hold the body, ensure the preservation of its upright position, walking, running. Muscles of the lower extremities - provide support and movement of the body.

Torso Muscles andLimbs:

A - front view: 1-deltoid; 2-large chest; 3-headed shoulder; 4-headed shoulder; 5-abdominal muscles;

6-tailor muscle; 7-four-headed thighs; 8-gastrocnemius; 9-extensors of the hand and fingers;

IN-viewbehind: 1-three-headed shoulder; 2-deltoid; 3-trapezoidal; 4-widest back;

5-flexors of the hand and fingers; 6-gastrocnemius; 7 double-headed femur; 8 gluteal.

Muscle Work

The movement of the body is due to muscle contraction.

When muscles contract, they do work. When the muscles contract, the bones approach or move away, moving the body or its parts, lift or hold the load.

Muscles providing movement are divided into:

1.Flexors and extensors,

2. Leading and discharging,

3. Rotating the bone clockwise and counterclockwise.

The same muscle cannot bend and unbend the bones in the joint,

and the movement of bones and, along with them, parts of the body is produced by at least two muscles (in fact, there are much more of them). Muscles are not always located where their strength is applied.

Amplitude - range of motion- depends on the length of muscle fibers,

and strength- from the cross-sectional area of ​​the muscle bundle.

To bend the hand into a fist, the muscles must be of sufficient length. This is why the muscles that flex and extend the fingers are on the forearm,

muscles that lower and raise the shoulder - on the trunk, etc.

Opposite-acting muscles are called antagonists,

and muscles acting in one direction synergists... They work in concert.

When the flexor muscles contract, the extensor muscles relax.

When the extensors contract, the flexors relax.

The somatic part of the nervous system regulates the work of skeletal muscles.

Both muscle groups can be relaxed at the same time (arms hang freely along the body). By holding weights in outstretched arms, the flexor and extensor muscles work together to push the bones together. Here they act as synergists.

Any work involves energy consumption.

The source of energy in the body is biological oxidation and decay of organic matter. With muscle contraction, energy consumption and waste of organic substances, most often glucose, increase.

All human movements occur due to the transfer of forces from the muscles to the bones, while the effort in the skeletal muscles develops as a result of their contraction. Each of the muscles or muscle groups can provide movement in only one direction, the opposite movement is carried out by other muscles - antagonists. In the cervical region, these functions are performed by the flexor and extensor muscles of the neck, which move the head and keep it in an upright position.

Since the center of gravity of the head is in front of the spine, maintaining the vertical position of the head requires constant coordinated work of all muscles of the cervical spine, which causes a fairly high load on them.

Neck extension

Muscles that perform neck extension include the following:

1. Trapezius muscle. It is located at the back of the torso. The upper end of this muscle is attached to the clavicle, the lower end to the axis of the scapula. With a bilateral contraction, the effort developed in it is aimed at extending the head and neck. Its one-sided contraction will help to turn the head in the opposite direction to this side.
2. Plaster muscle. It is located under the trapezoid. When contracting on both sides, the muscle bundles unbend the neck and tilt the head back. Its unilateral contraction will accompany the turn of the head and neck in this direction.
3. The erector spine is a long extensor muscle that runs from the sacrum to the occipital bone along the entire spine. It is the extensor of the spine and neck, tilts the head back.

Flexion of the neck

Neck flexion occurs due to the contraction of the neck flexor muscles, which include:

The sternocleidomastoid muscle. This flexor (flexor muscle) is located on the anterolateral surface of the neck, passing diagonally through the cervical spine. With rapid movements, the bilateral flexor contraction flexes the neck. Contraction of it only on one side will help to turn the neck in the opposite direction.

The scalene muscles, which are three groups of muscle fibers, are located under the sternocleidomastoid muscle on the anterolateral surface of the neck. With rapid movements, bilateral contraction of these muscles develops an effort that tends to bend the neck. If one side of them takes part in the reduction, then this will lead to a turn of the head in this direction.

The movements of the cervical spine are performed by different groups of muscles of the flexors and extensors of the neck, which at the same time always perform work, being in a state of contraction or relaxation.

Pain in the neck

Many have experienced this unpleasant phenomenon, which is due to inactive work, improper organization of the workplace, heavy physical exertion, drafts, a sharp turn or tilt of the head, getting into an accident. In simpler situations, pain can go away quickly, even by itself. However, if the process is delayed, you should consult a doctor to establish the true causes of neck pain.

Among them, the most common are the following:

• Muscle strain - occurs due to excessive stretching of the muscles, which leads to increased pain and swelling during movement.
• Myositis is an inflammatory process of the muscles. Its acute form requires compulsory treatment in order to avoid its transition to a chronic form, in which the neck muscles begin to regularly disturb the person when the weather changes, the load increases, and so on.
• Myofascial syndrome - developing as a result of prolonged muscle tension, while the spasmodic part of the muscles is converted into seals and bumps.
• Fibromyalgia is characterized by muscle tenderness and soreness.
• Neck and spine injuries.

In order not to be in a state of illness for a long period, it is necessary to carry out the necessary course of treatment in a timely manner, which will help get rid of limitation of movements and pain.

Strengthening the neck muscles

Given the high stress on the cervical spine, the importance of strengthening the neck muscles becomes apparent. This will also help to better protect the cervical vertebrae and protect them from injury. There are specially designed exercises for people suffering from discomfort in the neck area, aimed at overcoming these phenomena.

Regular implementation of a set of physical exercises will help maintain muscle tone and will, in addition, become a prophylactic agent for osteochondrosis, hernia of the cervical vertebrae, and so on. It is quite possible to perform such exercises at home. Swimming and restorative massage will be very useful for the muscles of the cervical spine.

Any type of influence on the physical body becomes many times more productive if a person understands what muscles he uses, how they depend on each other and how to work them out as much as possible to get a quick and high result. In this article, we will consider using simple and generally understandable examples of the extensor and flexor muscles, their work and interaction features.

What are the names of the muscles that are opposite in action?

The human musculature is arranged in such a way that many muscles have “brothers” that do the completely opposite work: at the moment when one muscle strains, the opposing muscle relaxes, and vice versa.

These muscles - flexors and extensors, which control the movement of the human body or individual limbs in space, are called antagonists. This is how a person makes movements - thanks to the control system strictly coordinated by the brain and the well-coordinated work of the muscles that move the skeleton.

How do they work?

The brain gives an impulse to the nerve endings of the muscle, for example, the biceps of the arm, and it, contracting, bends the arm. Triceps - the extensor of the arm - at this moment is relaxed, since the brain gave the corresponding signal to him.

The flexor and extensor muscles, that is, the antagonists, always work harmoniously, mutually replacing each other, but sometimes they can work simultaneously, maintaining a motionless, that is, static position of the body in space. A striking example of such work is the well-known plank pose, in which the body hangs motionless above the floor, resting only on the hands and toes. Most of the main flexors and extensors of the muscles in this position do exactly half of the work necessary for them, as a result, the body maintains this position. If a person does not strain, say, the abdominal muscles, then it becomes difficult for his back, since under the pressure of the force of gravity, the lower back begins to bend and sag. The arms lowered down along the body are completely relaxed antagonist muscles, and the arm extended in front of you to shoulder level is the synchronous work of both muscle groups.

What determines the quality of movement?

The high-quality work of the flexor and extensor muscles depends on several factors:

1. The range of motion mainly depends on the length of the muscle fibers and the factors that restrain them, for example, muscle spasm or post-traumatic scar greatly reduce the range of motion, and elasticity and good blood flow, on the contrary, significantly add the amplitude of muscle work. That is why it is important to warm up the body well with dynamic movements before training in order to saturate the muscles with blood.
2. depends on two aspects: the size of the lever that the muscle uses, and directly the number and thickness of the muscle fibers that make up it. For example, lifting a 10 kg kettlebell using the entire arm's length is easy (large lever), but lifting it only with a hand will be more difficult. Likewise, with the amount of muscle, having a diameter of 5 cm, several times stronger than the one that has a thickness of only 2 cm.
3. All muscle movements are controlled by the somatic nervous system, therefore, all body movements depend on the speed and quality of its work, especially the coordinated actions of the flexor and extensor muscles.

If an athlete knows about the correct work of the muscles, his training becomes more conscious, and therefore correct, the level of efficiency increases significantly with less energy consumption.

Examples of antagonist muscles

The simplest examples of flexor and extensor muscles are:

• The hamstrings and quadriceps are the flexor and extensor muscles of the leg, more precisely the thigh. The biceps is located in the back, attached to the ischium above and below, passing into the tendon, adjacent to the femur in the knee joint. And the quadriceps - the extensor, is located on the front of the thigh, is attached by a tendon to the knee joint, and the upper part is attached to the pelvic bone.
• The biceps and triceps are the flexor and extensor muscles of the arm located between the elbow and shoulder joints and are attached to them by powerful tendons. They are the main muscles that form the shoulder and control the vast majority of flexion and extension movements of the arm.

It can often be noticed that if there is an overly active extensor, then, as a result, the flexor muscle will be in a passive state, that is, insufficiently developed, which creates inappropriate body movements with a greater loss of energy than in harmoniously trained people (yogis are an example) ...

Another example of muscle antagonists

The rectus abdominis muscle and the longitudinal muscle along the spine, along with the psoas muscle, are also prominent representatives of the flexors and extensors of the body, and they are the most global ones, because thanks to their coordinated and uninterrupted work, the human body takes various positions in space: from the vertical position of the torso to bending into an arc or, on the contrary, backward bend.

And if a person is working to correct posture: eliminate kyphosis, correct scoliotic curvature or remove hyperlordosis in the lower back, he needs not only to work out the extensors of the spine and lumbar muscles, but also to actively pump the abdominal muscles, in particular the longitudinal abdominal muscle.

Pectoral muscles and rhomboid backs

These two couples are also considered antagonists, although they are often undeservedly classified in other categories. The interrelation of the spasm of the pectoral muscles and the passive rhomboid muscles of the back has repeatedly become an area of ​​research for physiotherapy and yoga therapists, kinesiologists and rehabilitation therapists. The pectoralis major and minor muscles are shaped like a fan. They are located on the front of the chest, originate in one bundle at the clavicles, the lower one at the upper abdominal wall and are attached to the crests of the humerus. Spasm of the pectoral muscles can be determined not only by the stoop of a person, but also by the position of his hands, lowered along the body. His arms from the shoulder and down to the hand will be turned inward, that is, the hands will look back with the palms.

They are located between the shoulder blades, controlling their work together with the trapezium, which, in turn, directly depend on the freedom of the shoulder muscles, in the area of ​​which there is already an attachment of the pectoral muscles. As a result, a person works on a stoop, loading the muscles of the back, but in fact, he needs to first get rid of hypertonicity of the pectoral muscles, then work out the muscles of the extensors and flexors of the neck, which will give freedom to his posture.

Sport is the key to health and visual appeal, which is why these days more and more people devote time to visiting gyms. Upper body training tends to be of the greatest focus and concern for beginners. Every day, attention is paid to exercises that pump the biceps, triceps and other muscles in the arms. At the same time, the technique often remains simply awful. All this comes from ignorance of the anatomical structure of human muscles. A deep understanding of the process and the degree of involvement of a particular muscle in the exercise will maximize the load on the target muscle and achieve the best result.

What is included in the concept of "arm muscles"?

Anatomically, the muscles of the human hand can be divided into two main groups:

1. Shoulder muscles - originate from the deltoids and extend to the ulnar muscle.

2. Forearm muscles - start from the elbows and include all the muscles down to the fingertips.

Human shoulder structure

The shoulder muscles are divided into the following groups:

1. Flexors of the arm (anterior brachial muscles), which include the brachialis, coracohumeral muscles, and biceps.

2. The extensors of the arm (back muscles of the shoulder), which include the triceps and ulnar muscles.

Arm flexors

Considering in more detail the anatomy and functional purpose of this element, it should be noted that the brachial muscle provides flexion of the forearm. The biceps, also called the biceps brachii, is designed to flex the upper limbs at the elbow and shoulder joints, and to rotate and rotate the forearm. It consists of a short and a long head. The coracohumeral muscle is directly involved in flexion and rotation of the arm in the elbow and shoulder joints.

Arm extensors

The main extensors are the triceps - the muscles of the arms, which are also called the triceps of the shoulder. They consist of a long, medial and lateral heads. The main functions of the triceps are extension of the forearm in the shoulder and elbow joints, as well as adduction of the upper limbs to the trunk. The elbow muscle helps the triceps to extend the arm at the elbow joint.

Forearm muscle structure

The muscles of the forearm are similar in their division to the shoulder muscles (they are also divided into front and back), while each of the subgroups given is subdivided into deep and superficial layers of muscles.

Front group

Consider the muscles of the hands of the surface layer of the anterior group, which include the following elements:

2. The radial flexor of the wrist - performs functions adjacent to the elbow flexor, and also penetrates the forearm.

3. The pronator round is a smaller muscle that completely repeats the functions of the two previous ones.

4. Superficial flexor of the fingers - takes part in flexion of the elbow joint and hand, as well as the middle phalanges.

5. Palmar muscle - controls the palm and takes part in flexion of the elbow joint.

The deep layer is represented by the following muscles:

1. Long flexor of the thumb - flexes the thumb and nail phalanx.

2. Deep flexor of the fingers - flexes the hand and extreme phalanges.

3. The square pronator is the main pronator of the forearm.

Back group

The superficial layer of the posterior group consists of the ulnar, short and long extensors of the wrist, the extensor of the fingers, as well as the brachioradialis muscle, which flexes the upper limb at the elbow, turns and penetrates the forearm. The deep layer consists of the long and short extensor muscles and the long abductor muscles of the thumb, which abduct and extend the human thumb. Also to this layer belong the extensor of the index finger, the functions of which are clear from its name, and the instep support, which controls the hand and forearm.

Carpal muscles

The human hand consists of nine muscles, the main functions of which are flexion and extension of the fingers, as well as ensuring their static positions: the short flexors of the thumb and little finger, the abductors of the thumb and little finger, the muscles opposing the thumb and little finger, the muscle that sets in motion thumb, vermiform and interosseous muscles.

Thus, on human hands there are many different muscles that have a huge number of functions.

Training of muscle groups of the upper limbs

How to train your arm muscles correctly? Human anatomy allows the upper limbs to respond fairly well to training. Each muscle has certain movements, and therefore, it requires specific pumping exercises. So, the biceps is responsible for bending the arm, therefore, various exercises for lifting weights (barbells, dumbbells) by bending the arm at the elbow from various positions (sitting, standing) will be effective. Triceps works to straighten the arms. Exercises involve the application of efforts at the moment when the muscles of the arms are straightened (push-ups on the uneven bars, extension from behind the head, and so on). For the muscles of the forearm, wrist flexion and extension, as well as exercises with an expander (or rubber ball) are best suited.

A nice feature of the arm muscles is their ability to quickly recover from workouts, which makes more frequent pumping possible. But in training arms, however, like any other muscle group, the main thing is not to overdo it, otherwise you can achieve the opposite result - constant fatigue and even injuries.

Why does a man need muscles?

Without muscle, people would be weak. For example, a loader - he would not be able to lift heavy bags

Explains the student of the 2nd grade Kolya.

Muscle work

Muscles, contracting or straining, perform work. It can be expressed in the movement of the body or its parts. Such work is done when lifting weights, walking, running. This is a dynamic job. When holding parts of the body in a certain position, holding a load, standing, maintaining a posture, static work is performed. The same muscles can do both dynamic and static work.

By contracting, the muscles set in motion the bones, acting on them like levers. The bones begin to move around the fulcrum under the influence of the force applied to them.

Movement in any joint is provided by at least two muscles acting in opposite directions. They are called flexor muscles and extensor muscles. For example, when the arm is flexed, the biceps brachii muscle contracts and the triceps muscle relaxes. This is because stimulation of the biceps muscle through the central nervous system causes the triceps muscle to relax.

Skeletal muscles attach on both sides of the joint and, when they contract, make movement in it. Usually, the flexor muscles - flexors - are located in the front, and the extension muscles - the extensors - behind the joint. Only in the knee and ankle joints, the anterior muscles, on the contrary, produce extension, and the rear ones - flexion.

Muscles lying outside (lateral) of the joint - abductors- perform the function of assignment, and lying inward (medially) from it - adductors- casting. Rotation is performed by muscles located obliquely or transversely with respect to the vertical axis ( pronators- rotating inward, instep supports- outwards). Usually several muscle groups are involved in the implementation of the movement. Muscles that simultaneously move in one direction in a given joint are called synergists(brachial, biceps shoulder muscles); muscles that perform the opposite function (biceps, triceps muscle of the shoulder), - antagonists... The work of various muscle groups occurs in concert: for example, if the flexor muscles contract, the extensor muscles relax at this time.

Nerve impulses are used by muscles. One muscle receives an average of 20 pulses per second. In each step, for example, up to 300 muscles take part and many impulses coordinate their work.

The number of nerve endings in different muscles is not the same. There are relatively few of them in the muscles of the thigh, and the oculomotor muscles, which perform fine and precise movements all day long, are rich in motor nerve endings. The cerebral cortex is unevenly connected with individual muscle groups. For example, huge areas of the cortex are occupied by motor areas that control the muscles of the face, hand, lips, feet, and relatively insignificant areas - by the muscles of the shoulder, thigh, and lower leg. The size of individual zones of the motor area of ​​the cortex is proportional not to the mass of muscle tissue, but to the subtlety and complexity of the movements of the corresponding organs.

Each muscle has a double neural subordination. One nerve carries impulses from the brain and spinal cord. They cause muscle contraction. Others, moving away from the nodes that lie on the sides of the spinal cord, regulate their nutrition.

Nerve signals that control muscle movement and nutrition are consistent with neural regulation of muscle blood supply. It turns out a single triple nervous control.

For fine control of muscle activity, regulation of the tension developed by each individual muscle is necessary. Such regulation is carried out in one of two ways (or both at the same time):

1. The number of muscle fibers growing at any given moment can vary. The strength developed by the muscle will be the greater, the greater the number of stimulated fibers, and vice versa. This is usually the case in skeletal muscle.

2. The frequency of nerve impulses arriving at the muscle fibers may change. Thus, more frequent stimulation will also lead to an increase in muscle strength.

Muscle contraction in the body occurs smoothly and in a coordinated manner. This is provided by the asynchronous contraction of different groups of muscle fibers in the antagonist muscles.

Types of movements produced by pairs of antagonistic muscles