Posture: peculiarities of studying and evaluating human posture

Currently, one of the indicators of the socio-economic development of modern society is the life expectancy of citizens, which largely depends on health, physical activity and physical education. Unfortunately, in recent years, Ukraine has seen a trend towards a decrease in the main indicators of health of the population, especially children and young people. According to statistics, today 80% of schoolchildren have significant deviations in physical development. At the same time, the number of people regularly engaged in physical education and sports is sharply reduced.

Posture disorders are one of the most pressing problems of children's health. These disorders usually arise due to irrational motor regime of children and create unfavorable conditions for the functioning of various organs and systems of the human body.

In specialized medical manuals, posture is defined as the habitual position of a person standing at ease without active muscle tension.

Morphologically, posture is defined as the habitual pose of a relaxed standing person, which he/she adopts without excessive muscle tension. From the point of view of physiology, posture is a skill or a system of certain motor reflexes, which ensures the correct position of the body in space in statics and dynamics. In biomechanics, posture is considered as a relaxed pose of the human body in an orthograde position, assessed taking into account the geometry of the human body masses.

In the vertical position, the head is held by the head extensors against the moment of its gravity. Due to cervical lordosis, the mass of the head is directed at bending the cervical spine, and the neck muscles also perform the holding work. Holding the head, with some lowering forward, reflexively contributes to an increase in thoracic kyphosis. Holding the head with a slight bending of the cervical spine contributes to a decrease in thoracic kyphosis.

Posture can be assessed by the geometry of the human body mass, since one of the reasons for its violations is the occurrence of an excessively large overturning moment relative to one or two planes of space occupied by the human body. This causes excessive tension in the extensor muscles and deformation of the longitudinal axis of the spinal column.

The term "mass geometry" was proposed by the Frenchman Anton de la Goupière in 1857. At present, the geometry of body masses characterizes the distribution of the biolinks of the human body in space relative to the somatic frame of reference, includes data on the location of the common center of mass, moments of inertia of biolinks relative to their axes and planes of rotation, ellipsoids of inertia and a number of other indicators.

The geometry of human body masses has been studied for a long time by many authors with varying degrees of rigor, reliability and objectivity.

The desire to study and identify patterns in the dimensions of the human body arose in ancient times in Egypt, intensified during the heyday of Greek classical art, and achieved its greatest results during the Renaissance.

At different times, many systems for calculating the sizes and proportions of the body - the so-called canons - were proposed. When using a canon, the length of some separate part of the body (module) was usually taken as a unit of measure. Using this unit of measurement, it is possible to express the size of each part of the body through it, considering that on average it is a multiple of the dimensions of this module.

The modules proposed were the height of the head, the length of the middle finger, and the length of the spinal column.

Even the ancient Egyptians believed that the length of the middle finger of the hand is equal to the length of the entire body 19 times.

The first of the known canons was created in the 5th century BC by Polycleitus. He took the width of the palm at the level of the root of the fingers as a module.

During the Renaissance, Leonardo da Vinci contributed much to the teaching on the proportions of the human body. He took the height of the head as a module, which was 8 times the height of the human body.

We know almost nothing about the proportions of the human body established by Michelangelo. However, it is known that he was constantly studying the proportions of the human body, as evidenced by his drawings and sketches.

Kolman proposed a canon in which the human body was divided into 100 equal parts. With this decimal system of proportions, the sizes of individual body parts could be expressed as percentages of the total height. Thus, the height of the head was 13%, the length of the body - 52-53%, the length of the leg - 47% and the arm - 44% of the total body length.

Most of the canons proposed later were built on a different principle. The module was taken to be the most constant in its dimensions part of the skeleton - the spinal column, and not the whole thing, but 1/4 of it (the Fritsch-Stratz canon).

Of great interest are the studies of proportions by Karuzin (1921). The canon he created is based on the geometric construction of the figure according to Fritsch-Stratz. Supplementing the proportions of the lower limbs, Karuzin introduced the size of the foot length into their system of measurements, and also outlined the width of the pelvis (intertrochanteric diameter). When taking into account the sizes of the upper limbs, the author added the width of the shoulders.

To determine the relationship between the linear dimensions of the human body segments and its height, the value "pars" was introduced, equal to 1/56 of a person's height.

As is known, the proportions of a living body are very variable, in particular, they depend on the type of physique. Currently, there are more than a hundred classifications of human constitution based on various features. Therefore, there are constitutional schemes based on morphological, physiological, neuropsychic and other criteria. Attempts to divide people into types by physique have been made in practical anthropology for as long as anthropology itself has existed.

Hippocrates (460-377 BC) distinguished between bad and good, strong and weak, dry and wet, elastic and flaccid constitutions. In ancient Indian medicine, there are such typological characteristics of people as "gazelle", "doe", "elephant-like cow", etc.

Later, Galen developed the concept of habitus, meaning the set of morphological features that characterize a person’s appearance.

In 1914, Sigo proposed to define the human constitution by four main organ systems - digestive, respiratory, muscular and nervous. Depending on which system prevails, the author identified four types of human constitution: respiratory, digestive, muscular and cerebral.

Representatives of the respiratory type have all air sinuses and airways well developed, they have a long chest, a small abdomen, and are above average in height.

Representatives of the digestive type have a large belly, a conical, expanded downwards chest shape, an obtuse substernal angle, short stature, and a highly developed lower part of the head. They have highly developed sections associated with the digestive organs. The high position of the diaphragm causes the heart to be horizontal.

• The muscular type is characterized by a well-developed musculoskeletal system. The chest of people of this type is cylindrical, wider than that of people of the respiratory type.
• The cerebral type is characterized by the development of the brain skull. The body is slender, the substernal angle is acute.

Shevkunenko and Geselevich (1926), based on the relationship between the shapes of individual body parts, identified three types of human constitution:

• Dolichomorphic type - characterized by longitudinal body dimensions, above average height, long and narrow chest, narrow shoulders, long limbs, short torso.
• Brachymorphic type - squat, wide, with well-defined transverse dimensions, a long body, short limbs, neck and chest.
• Mesomorphic type - characterized by intermediate features (between dolichomorphic and brachymorphic types).

German psychiatrist Kretschmer (1930) identified types of human constitution based on morphological features that were close to Sigo's classification. He distinguished three types: pyknic (Sigo's digestive type), asthenic (cerebral) and athletic (muscular). Kretschmer assumed that all people could be classified according to their predisposition to a particular mental illness.

Chernorutsky (1927), based on the study of the location of organs, their shape, and metabolic features, proposed to distinguish three types of constitution: asthenic, normosthenic, and hypersthenic. In determining constitutional types, the author used the Pignet index:

I = L - (P+T),

Where I is a dimensionless index; L is body length, cm; P is body weight, kg; T is chest circumference, cm. This scheme has been widely used in medical practice.

Asthenics usually have longer lungs, a small heart, low blood pressure, high metabolism, increased functions of the pituitary gland, thyroid and sex glands, decreased function of the adrenal glands, and a tendency for organs to shift downwards.

Hypersthenics are characterized by a high position of the diaphragm, horizontal position of the heart, short but wide lungs, hypersecretion of the adrenal glands, high blood pressure, high levels of hemoglobin and red blood cells in the blood.

In normosthenics, all indicators fluctuate within the average values. Based on the development of connective tissue (histological principle), Bogomolets (1928) identified four types of human constitution:

• The asthenic type is characterized by the development of predominantly loose connective tissue, which has the ability to be highly reactive and resistant.
• Fibrous type - with a large development of dense fibrous connective tissue.
• Pastose type - loose, "raw", "edematous" connective tissue, prone to fluid retention.
• Lipomatous type - highly developed fatty tissue. All the constitutional schemes considered were applicable mainly to men.

Shkerli (1938) developed a classification of constitutional types for women based on the amount and nature of fat deposits. He identified two main types with subtypes:

Type I - with uniform distribution of subcutaneous fat layer:

• normally developed,
• highly developed,
• poorly developed fat layer.

Type II - with uneven fat deposition:

• in the upper half of the body - the upper subtype,
• in the lower half of the body - lower subtype.

Fat deposits can be localized either in the trunk area (usually in the mammary glands or abdomen), or in the gluteal region and in the greater trochanter area.

A slightly different classification of constitutional types for women was proposed by Talant. It is based on both morphological features and psychophysical differences. The author proposed to identify 7 constitutions, combining them into three groups.

Group I: leptosomal constitutions with a tendency to grow in length.

• The asthenic type is characterized by a thin build, long limbs, narrow pelvis, retracted abdomen, poorly developed muscles, and a narrow, long face.
• The stenoplastic type is narrowly built, has good overall nutrition, moderate development of all tissues, and approaches the ideal of female beauty.

Group II: mesosomal constitutions with a tendency to grow in width.

• The pyknic type is characterized by relatively shortened limbs, a rounded head and face, a wide pelvis with characteristic fat deposits, and relatively wide and rounded shoulders.
• The mesoplastic type is characterized by a squat, stocky figure, a wide face, and moderately developed muscles.

Group III: megalosomic constitutions - equal growth in length and width.

• Euryplastic type - "obese athlete type". This type is characterized by strong development of fat with pronounced features of the athletic type in the structure of the skeleton and muscles.
• Subathletic type, or a true feminine type of constitution with an athletic body structure. These are tall, slender women of a strong build with moderate development of muscles and fat. The athletic type is characterized by exceptionally strong development of muscles and skeleton, weak development of fat, narrow pelvis, masculine facial features.

In 1929, Shtefko and Ostrovsky proposed a scheme of constitutional diagnostics for children. This constitutional scheme is based on fat deposition, the degree of muscle development and the shape of the chest. The scheme is applicable to both boys and girls. The authors identified five normal types: asthenoid, digestive, thoracic, muscular, abdominal and, in addition, mixed types: asthenoid-thoracic, muscular-digestive, etc.

• The asthenoid type is characterized by a thin and delicate skeleton. The lower limbs are predominantly developed, the chest is thin and tapering downwards, the substernal angle is acute, the abdomen is poorly developed.
• The digestive type is characterized by a strongly developed abdomen, which, protruding, forms folds above the pubic surface. The substernal angle is obtuse.
• The thoracic (chest) type is characterized by a strong development of the chest (mainly in length) with simultaneous development of those parts of the face that participate in breathing. The chest is long, the substernal angle is acute, the abdomen is relatively small, shaped like a pear with the base facing downwards, the vital capacity of the lungs is large.
• The muscular type is characterized by a uniformly developed body. The chest is of medium length, the substernal angle is of medium size, the shoulders are high and wide, the abdomen is shaped like a pear with the base facing upwards. The muscles are strongly developed, especially on the limbs. Fat deposition is insignificant.
• The abdominal type is a special modification of the digestive type. It is characterized by significant development of the abdomen with a small chest, not very developed fat layer, significant development of all parts of the large intestine.

Research conducted by Davydov (1994) made it possible to identify age-related characteristics of the distribution of preschool and primary school children according to constitutional types.

The data obtained by the author indicate that significant changes of morphological and functional order occur in the process of physical activity, while the nature of their influence is ambiguous for different systems of the body and is not the same in different periods of ontogenesis. The author identified conservative (development rhythm, linear dimensional features, histological characteristics) and labile (functional systems, body weight) components of the morphology and functions of the human body in relation to the effects of physical exercise. Based on the data obtained, the permissible possibility of using physical activity as a regulator and stimulator of morphofunctional development in human ontogenesis was determined.

It should be noted that there is no single approach to defining the human constitution. This applies both to the definition of the concept of "human constitution" and to constitutional diagnostics - the characterization of constitutional types. In specialized literature, most specialists tend to use the term "somatotype" to characterize the constitution.

Currently, among the many schemes of normal constitutions, researchers usually distinguish three constitutional body types:

• pyknic endomorphic type - convex chest, soft rounded shapes due to the development of the subcutaneous base, relatively short limbs, short and wide bones and feet, large liver;
• athletic mesomorphic type - trapezoidal body shape, narrow pelvis, powerful shoulder girdle, well-developed muscles, rough bone structure;
• asthenic ectomorphic type - flat and long chest, relatively wide pelvis, thin body and weak development of subcutaneous base, long thin limbs, narrow feet and hands, minimal amount of subcutaneous fat.

Naturally, the constitutional features of most individuals could not be reduced to these three types. Such a division gives only a general idea of the range of fluctuations in the human constitution. Therefore, for example, in the practice of sports selection, they focus not on extreme types, but on continuously distributed components of the physique, of which three can be distinguished: endomorphic, mesomorphic and ectomorphic. The degree of expression of the components varies among individuals and can be assessed using a seven-point system (7-1). The highest score (7) corresponds to the maximum degree of expression of the component. The description of the somatic type is made with three numbers. For example, the somatotype expressed by the numbers 7-1-1 is characterized by a rounded shape, strong development of the subcutaneous base, weak muscles, large entrails (pycnic type) with weak expression of the mesomorphic and ectomorphic components (mesomorphy indicates an athletic physique, and ectomorphy - an asthenic physique). Extreme variants such as 1-7-1, 2-1-7 are rare, the most common somatotypes are 3-5-2, 4-3-3, 3-4-4. It should be noted that all three components are interdependent: an increase in one leads to a decrease in the others. Therefore, high values of one component practically exclude high values of the other two. When assessing a somatotype, the sum of the three assessments should not exceed 12 and cannot be less than 9 points.

[ 1 ], [ 2 ], [ 3 ], [ 4 ], [ 5 ], [ 6 ]