The human musculoskeletal system includes three relatively independent systems: the bone (or skeleton), the ligamentous-articular (passive part), and the muscular (active part).

1. The Bone system (or skeleton) is a complex of the body's bones that form its solid Foundation. The skeleton has mainly a mechanical meaning. More than 200 bones take part in the formation of the adult skeleton.

From the course of biology, it is known that the structural and functional unit of living beings is the cell. In turn, a system of cells and non-cellular structures that have a common structure and origin, specializing in performing certain functions in biology, is called a tissue.

There are the following types of tissues: epithelial, connective, muscular, and nervous.

The bones include all types of tissues, but the connective tissue is the leading one. It is represented by bone and cartilage tissues. The structure of such tissues is characterized by the fact that they have few cells, but many non-cellular structures. Non-cellular structures of bone tissue consist of organic compounds (osein and ossemucoid), which give the bone elasticity, and inorganic (salts, mainly calcium), which give the bone strength and elasticity.

Cartilage tissue (hyaline cartilage) covers the articular ends of bones, i.e. the articular surfaces.

Microscopically, the bone consists of osteons and bone plates located between them. The osteon is the main structural unit of bone. Osteones not only create the structure, but also provide functional stability, increase the strength properties of the bone for compression, bending and stretching. One square millimeter of cross-section of bone tissue can withstand a compression load of up to 16 kg, and a stretching load of up to 12 kg.

There is a General pattern that is characteristic of all tissues and organs-it is better to bear the load on compression than on stretching. This is due to the constantly acting on the body of the earth's gravity (gravity) and the adaptation of all living creatures and tissues to this effect.

Osteons are rebuilt over the course of life in connection with the climatic and geographical environment, with the mechanical conditions of bone functioning, age, nutritional characteristics, and other factors.

Bones are classified into tubular (long and short), which have a medullary cavity inside; spongy (long and short), which do not have a medullary cavity and are similar to foam rubber on incisions; flat; mixed.

Tubular bones have a body (diaphysis) and two ends (epiphysis). The internal structure of the epiphyses of tubular bones has a typical spongy structure. Moreover, the bone plates (trabeculae) of the spongy substance are oriented along the lines of compression and stretching forces, are located to each other at an angle of 90o, and in relation to the resultant of these forces – at an angle of 45 degrees.

Changes in the structure of the bone system associated with increased physical activity, due to physical labor, exercise, certain conditions of military labor, sports, are unidirectional. If physical activity does not lead to a deterioration of the overall functional state of the body, then they are favorable. However, it is very difficult to determine the degree of functional state at a given time. Therefore, it is difficult to recommend the amount of physical activity at the moment. In some cases, when training loads "for health", undesirable changes occur in the bones, leading to arthrosis of the joints and the cessation of sports (we are talking about boxing, karate, sambo, judo, etc.).

The bone is a fairly plastic organ that quickly changes its structure (rebuilds) with increased or reduced loads. There is a restructuring at the molecular, cellular, tissue and organ levels. Macroscopically visible bone changes with increased physical activity are detected on radiographs after 1 year of exposure to the load of the training regime. Maximum reconstructions of the bone structure, its appearance and shape occur after 5–5,5 years of sports, work, etc.

The following main functional patterns of bone growth are noteworthy:

1. Mechanical loads change the longitudinal and transverse dimensions of bones to a different extent. The former are more genetically determined than the latter. Therefore, mechanical loads are more reflected in the growth of bones in thickness and width than in length.

1. When the mechanical load increases to a certain level, bone formation increases, and when this level is exceeded, the activity of bone formation decreases.
2. The level of optimal mechanical load depends on the individual characteristics of the person, i.e. on the functional state of the body at the moment.

Need to know:

• bone growth and modeling of the skeleton (the appearance and severity of bumps, bumps, roughness, pits and dimples) in a person occurs by the age of 25 (at the time of maturation);
• starting from the age of 30, all people develop involution at the cellular level, which eventually becomes visible at the tissue and organ levels. In the bone system, there are processes of either rarefaction of bone tissue (osteoporosis), or its compaction (osteosclerosis).

By its nature, the bone has great strength. In terms of compression resistance, bone is 10 times stronger than cartilage. The compressive strength of the bone is one and a half times greater than the tensile strength. The compressive strength of hyaline cartilage is 3 times greater than the tensile strength. Fresh bone is 5 times stronger than reinforced concrete for both compression and stretching. To crush the tibia by pressure-you need about 4000 kg.

Compared to the strength of bone tissue, the tensile strength of the tendon is 15 times greater, and the strength of the rib cartilage is 1.5 times greater. It should be noted that the mechanical properties of connective tissue may not be the same not only in different individuals, but also in the same person, changing due to nutritional conditions and features of functional and age-related character.

2. The Ligamentous-articular system is an important organ of the musculoskeletal system. It provides a certain amount of movement of the skeleton links relative to each other and relative to the support area.

Joints are discontinuous, hollow, mobile joints of bones. Each joint has three main elements: the articular surfaces, the articular bag, and the articular cavity.

The articular surfaces of articulating bones are covered with articular cartilage.

The joint bag (capsule) consists of an external (fibrous) and internal (synovial) layer.

The articular cavity is limited by the articular capsule and the articular surfaces of the extremities. This slit-like space contains a small amount of synovial fluid.

In addition to the 3 main elements, there is an auxiliary device: articular ligaments, articular discs and menisci, synovial bags.

In strengthening the joints, the tension of the joint ligaments, the pull of the muscles passing near the joint, atmospheric pressure (if the joint is sealed), and the capillary tension of the synovium between the articular surfaces of the bones are important. Due to these factors, joints are particularly strong organs. Ruptures of the body or its parts occur in the area of the diaphyses (bodies) of bones and never in the area of joints, if the joints are sealed, and the force acts on the axis of the organ. Damage to the joints is possible with forces acting at an angle, or on twisting.

Practice shows that the joints, due to often developing arthrosis, are the most limiting organs.

Constant strong irritation of the bone-hyaline cartilage zone during intensive training without taking into account individual characteristics in order to achieve faster results (especially in athletes-boxers, karate, Sambo, judo, etc.) leads to the replacement of cartilage with bone, a decrease in the height of hyaline cartilage, narrowing of the joint gap, deterioration of joint lubrication due to the secretion of synovial fluid, the appearance of bone outgrowths (spines) along the edge of the articular surfaces, calcification of ligaments and the joint capsule. All this fits into the diagnosis-arthrosis of the joint, or joints, which is accompanied by limited mobility in the joints. A person experiences severe pain when moving and, sometimes, quickly becomes disabled.

Therefore, it is necessary to constantly think about the mode and intensity of movement, rest mode from the position of normalization of the functional state of the ligamentous-articular system of the trainee.

Properly organized training can significantly increase the volume of movement in the joints without pathological manifestations, or reduce it. The movement factor can change the shape of the joint, which is manifested by a large amount of movement.

It is advisable to use such exercises that will facilitate the acquisition of movements in the joints along the 3 axes, i.e. using all three degrees of freedom.

3. Muscle

Muscle is an organ, which is composed of striated muscle fibers. In addition, it includes connective tissue, blood vessels and nerves. The muscle is surrounded by a connective case-fascia.

There are more than 600 individual muscles in the human body. Each of them consists of the body (abdomen), which is the active (contractile) part and tendons (passive part), through which the muscles are attached to the bones.

The main property of muscle tissue is its contractility. There are three types of muscle tissue: non-striated (smooth), striated (striated, skeletal) and cardiac.

Undefined muscle tissue is found in the walls of blood vessels, excretory ducts of glands, the wall of the stomach, intestines, bronchi, ureters, bladder and other organs, as well as in the skin. The structural unit of this type of tissue is the myocyte cell. Contractions of smooth muscle tissue occur slowly, rhythmically and involuntarily.

Striated muscle tissue is so called because of the characteristic striation visible under the microscope. This tissue forms the muscles that drive the skeleton, and therefore is also called skeletal muscle tissue. By function, it is arbitrary, since its contractions and relaxations are subject to the will of the person.

The cells of this tissue or fiber are its structural units and resemble cylinders. Muscle contraction occurs due to shortening of muscle fibers (cells). Shortening of the fibers occurs in the type of folding telescope.

There are fibers of the first type (red) and fibers of the second type (white).

Muscles with a predominance of red fibers are able to stay in work for a long time, in contraction, while they do not develop much muscle strength and do not get tired.

Muscles that are dominated by white fibers are considered fast. They are able to quickly develop maximum strength, but can not work for a long time, quickly get tired.

Comparison of a number of limb muscles revealed a mosaic character in the distribution of fibers of the first and second types.

Heart muscle tissue has in its structure the features of uncharted and striated muscle tissue. Functionally, the heart muscle also inherited properties from non-striated muscle tissue-involuntary and strength of contraction, and from striated – the speed of contraction.

For the muscular system, as for the bone, when doing physical labor, hand to hand combat unidirectional characteristic of the restructuring, which are two mechanisms for increasing the size of the body: muscle hypertrophy (due to increase of volume of cells) and hyperplasia (by increasing the number of cells).

As described, it becomes apparent how important is the knowledge structure of the human muscular system for training a specialist of martial arts, to develop the necessary muscle groups during training, but also for the ability to consume energy during hand-to-hand combat, redeployment and recovery.