In this article we will discuss about:- 1. Importance of Physical Growth 2. How Physical Growth is Studied? 3. Some General Characteristics 4. Important Aspects.
Importance of Physical Growth:
An understanding of the physical growth and motor development of children is essential in promoting healthy growth and the happy adjustment of children. Yes, most of us, teachers and parents, fail to appreciate the full significance of physical growth and motor development. Physical growth is related to mental growth. Many aspects of the child’s mental development are directly dependent on his physical growth. The malfunctioning of the physical organs is, sometimes responsible for deviate behaviour.
For example, nervousness and emotionality are very pronounced in adolescence and are the out-growth of the physiological changes during this period. Equipped with this knowledge, both teachers and parents, are in a position to guide the development of children.
Heredity determines the major course of physical growth and environment modifies its details. Although the primary responsibility for physical growth and health is that of home and parents, yet, teachers can greatly contribute to this by being able to do what parents cannot achieve in this direction.
How Physical Growth is Studied?
Physical growth can be studied both horizontally and longitudinally. The horizontal approach is also called cross-sectional approach. A large number of children of each age level, or grade, race and sex are studied and measured for various, aspects of growth. This results in obtaining ‘norms’ or ‘standards’ for different age groups. In the longitudinal method, a group of children are measured repeatedly at different ages as they grow older, year to year. The group remains the same from year to year.
It is very essential to see that the groups are large enough so that the influence of individual variations may be minimised. Both these methods throw light on the growth status. The longitudinal method, however, can explain the increment, rate of growth or growth progress. X-rays of internal body structures, photographs or ratings made during physical examination are other means of studying physical growth.
Some General Characteristics of Physical Growth:
A study of physical growth, undertaken by various research workers, has brought to light the following general characteristics of physical growth:
(a) Growth, is rhythmic, not regular. It comes in waves, or in cycles. Rapid growth is followed by a period of slow growth, and again rapid growth is resumed.
(b) Each organ and each part of the body follows its own laws of development. It follows the law of developmental direction. For the most part, development occurs first in the upper part of the body and later in the lower part of the body.
(c) There are growth cycles within the year. For example, in cold countries, July to December is the season most favourable for increase in weight. The period from May to early July, registers the least growth.
(d) Growth is very rapid from birth to the age of two and a half years; its rate declines from 2½ years to the beginning of pubescence. Adolescence is immediately preceded by a period when an increase is registered in the rate of growth. There is a gradual but continuous decrease in the rate of growth, following adolescence.
Important Aspects of Physical Growth:
1. Growth in Height and Weight:
The human baby is about 19 to 20 inches in length at birth. Slight variations may occur due to parentage, sex, and racial factors. For the first 2 years, the height increases rapidly. From the third to the sixth year, growth in height occurs at a slower rate. From the seventh to the tenth year, the rate accelerates; but it slows down again between the tenth and twelfth year. There is a rapid growth spurt in girls from ten to fourteen years, and from twelve to sixteen years in boys. The mature height is attained by eighteen to twenty years.
Boys are, on the average, taller than girls up to the eleventh year. From the twelfth to the fifteenth year, girls are generally taller than boys. At the age of fifteen plus, boys and girls are about the same height. After that boys are taller than girls and retain that superiority in height up to the eighteenth or twentieth year.
Studies have shown that improved feeding, especially during the earlier years of life, contributes to the height positively, later in life, that there is a positive correlation between height and intelligence and between favourable socioeconomic factors and height. Bright children and those coming from better socio-economically placed homes are, on the average taller than others.
The average weight of a human baby is between 5’A and 9 pounds; girl babies are generally lighter than boy babies. There is a loss of weight, five to eight percent, in the first seven days. This loss can be ascribed to a new type of nourishment and to the difficulty of becoming adjusted to a new method of taking nourishment.
The baby shows an increase in weight by the end of the first month. The weight doubles the birth weight, at the age of four months. It is three times the birth weight when the baby is one year old. The weight increases from three, to five pounds annually, from the second to the third year. The increase in weight slows down from the third year until the onset of puberty.
Studies show that boys are, on the average, heavier than girls at all ages except for two or three years, from eleven to fourteen, and that intelligent children are heavier for their height than are average children of the same age.
Satisfactory standards or norms for height and weight are not available in India owning to paucity of research in this field. A few stray researches that have been made show that the Indian children are lighter and shorter than the same age American children. They also show that economic status and diet have a profound effect on the height and weight of children, besides other factors.
2. Body Proportions and Physical Growth:
Human individuals differ not only in height and weight, but also in body proportions as they grow. At birth, the body proportions are different from those of an adult. It must be noted that not all parts of the body attain mature proportions at the same time. Some areas attain their mature size at one age while others attain maturity at earlier or later ages.
But, for the most part the different parts of the body have assumed adult proportions by the age of sixteen or seventeen years. The head grows proportionately less after birth than most other parts of the body. In the first month, the circumference of the head is two-thirds of that at three years, at 6 years, 90 percent of adult size; at twelve years, 95 percent of adult size. At every age, the proportions of the head of a boy are greater than those of a girl.
The facial skeleton becomes larger in proportion to the cranium from birth to seven years; thereby, eliminating the “babyish” look. The forehead flattens, the lips fill out, and the face becomes oval instead of round as the child reaches puberty.
The nose is one of the most disproportionate of the facial features. It is small and rather flat on the face in the first four years. It reaches, its mature size by the age of 13 or 14 years. The nose is disproportionate larger than the other features at this age. The early maturing of the nose is likely to arouse much concern and distress on the part of the adolescent.
The ‘trunk’ is top-heavy to begin with. Gradually, it lengthens as well as the legs. This results in good balance. During early adolescence the chest deepens and becomes longer. In girls, the pelvic arch broadens and the body circumference gets enlarged in the area of the hip. The legs and the arms which are disproportionate in the beginning attain the proper mature size by adolescence. Hands and feet grow rather rapidly during adolescence: the causes, mental anguish and self-consciousness among boys and girls.
The body proportions have intrigued many thinkers. Kretschmer gave us three types of people, based on the body proportions: the pyknic, the athletic and the asthenic types. Sheldon is another thinker who has given ‘somatotypes’ or body types. These types bring out three components: endomorphy denoting the degree of softness and roundness, mesomorphy denoting the degree of bone and muscle and ectomorphy denoting slimness and fragility. Most individuals are mixtures of these different body builds.
The growth of bones affects, to a great extent, the body-shape or body proportions. It consists of growth in the size of the bones, increase in the number of bones, and change in the texture of bones. The most rapid growth in size of bones is during early adolescence. The growth in bones is accompanied by muscular growth and disposition of fat under the skin. This results in change in looks and appearance.
One important aspect of the growth of bones is there, ossification or hardening of the bones. To begin with, bones are soft, but gradually they harden and reach their maximum, ossification at puberty. Ossification takes place due to calcium, phosphorus, and other mineral salts which are gradually introduced into the bone structure.
Connected with the growth of bones, is the eruption and development of teeth, both temporary and permanent. Studies have shown that in mentally subnormal children the eruption of teeth is delayed and many permanent teeth do not appear at all in these children as compared to normal children. Body proportions are also affected by the growth of the muscles.
There is a marked increase in the growth of muscle tissue in girls from the ages of twelve to fifteen years and from fifteen to sixteen years in boys. The marked increase in muscle weight after puberty is one of the secondary sex characteristics which accompanies the onset of puberty.
The circumference of the forearm, upper arm, calf and thigh increases because of the muscular development. The rapid growth in musculature and the disproportionate growth of bones in adolescence is responsible for faulty posture and uncertain co-ordination. It causes ‘adolescent awkwardness’ manifest in nervousness, squirming, pulling at neckties and twisting buttons. Once the muscular control is developed, repose or balance follows.
3. Physical Growth and the Development of the Nervous System:
The nervous system is marked by a rapid growth before birth and in the first three to four years after birth. There is an increase in the number of size of nerve cells during the prenatal period. After birth these immature cells attain mature development. An important aspect of the nervous system is the brain, whose growth is very rapid from birth to four years; it slows down between four and eight years.
It reaches the mature-size by the age of sixteen. At birth the weight of the brain is one-fourth of the adult brain; it is one-half by the age of nine months, three-fourths by the end of second year from fifth by the fourth year, and ninety percent by the age of six years. During adolescence and after there is not much increase in the size of the brain, but there is continuation of development in the cortical tissues and of inter-cerebral association tracts.
4. Physical Growth and Changes in Internal Organs:
The increase in the size and weight of the child is not due to the development of muscle or tissues alone. Changes in internal organs, during the growth years, also play an important role. These changes are connected with respiration, circulation and with digestion, in glands and in reproductive organs. In the words of Breckenridge and Vincent, “as the child grows, the heart beats stronger, more slowly and regularly; respiration becomes slower and deeper and more regular; food takes longer to pass through the digestive tract and digestion is not as easily disturbed; the bladder can retain urine longer; body temperature becomes more stable, the composition of the blood remains more nearly constant.” This increase in efficiency enables older children and adults to adjust to changes in environment and in routines more easily than young children.
Among the glands, the pituitary gland plays a vital role. It is mainly responsible for growth in the early years. It also arouses activity in other glands. Under its influence, the sex glands are stimulated and cause several changes in the organic system. These sex glands also interact on the pituitary gland in that they slow down the work of the latter. The restraining influence of the sex hormones prevents human being from growing into giants.
The sex-apparatus reaches its functional maturity at puberty. Studies have found a correlation between physiological maturity and superiority in the physical development. The maturity of sex-apparatus results in the mature functioning of the reproductive organs and in the development of secondary sex characteristics such as the growth of the beard, the appearance of hair on the body, a coursing of the texture of the skin and a change in voice in boys and a similar features in girls.
These physiological changes as well as secondary sex characteristics may produce anxiety, fear, worry in boys and girls as well as changes in disposition and temperament; for example, attitudes of dissatisfaction, restlessness and revolt against authority are very common. A number of adolescents threaten to leave home or commit suicide under the stress of these physiological changes, specially, if no worthwhile and timely guidance is forthcoming.
To conclude, we may say that physical growth of children has an important bearing on their behaviour. Physical strength, physical efficiency (which depends on health status) and size are important factors that determine children’s ideas about themselves and then relations with their companions in work and play. These factors evoke feelings of respect, obedience and a sense of adequacy and well-being in children – respect and obedience for elders and a sense of adequacy or positive self-feeling about ‘themselves’.