Physical growth and motor development begin immediately after conception, progresses through the pre-natal period, and continues to maturity at adolescence. Physical growth and motor development are important because they give every human being their size, poise, and dexterity. They are the basis of human locomotion. In this unit, we discuss the meaning, trends, and factors that influence physical growth and motor development. We also discuss the educational significance.

At the end of this page, you will be able to:

· Explain the following terms/concepts:

(a) Physical Growth

(b) Motor development

· Outline the trend in physical growth

· Discuss the developmental trend in motor development

· Describe two major factors that influence physical growth and motor development

· Examine the educational significance of physical growth and motor development.

 Meaning of Physical Growth and Motor Development

Physical growth describes increases in body height, mass or weight, gait, and body size. The organs, tissues, and systems of the body all experience growth. At birth, the average weight of children is about 2.5kg. By the age of 16 years or late adolescence, the weight reaches about 55 kg. At birth, the average child is under 50 cm or about 0.50m. By the age of one year, the average child is about 0.75m.

Medical practitioners describe the baby weight and height not just in absolute units of kilogrammes or metres, but as a percentile. If a child’s height is, for example, in the 80th percentile, then the child is taller than 80 per cent of children, their age, or shorter than 20 per cent of children, their age.

Increases in height and weight indicate changes in size and mass of the body tissues, muscles, and the skeleton. These changes do not tell much about the development of the child if they are not accompanied by changes in functions.

Motor development generally signals changes in the functionality of body tissues, muscles, and the skeleton. Motor development describes the baby’s greater control of their voluntary motor actions. Voluntary motor actions include reaching for things, grasping, manipulating objects, crawling, standing, and walking. These actions indicate more effective coordination among tissues, organs and systems of the body.

The following changes indicate motor development in the baby: At birth, an infant’s eyes roam about haphazardly. After a few days, the baby can stare at an object for a brief period. This indicates that there is a patterned connection between the muscles that move the eyes and 48 nerve impulses in the brain. By four weeks of age, an infant can follow a dangling object with its eyes. At four months, the same baby can simultaneously hold and look at a rattle. This means that the eyes and the hands are doing teamwork.

Motor development therefore describes more effective control and coordination of body organs and systems. Researches categorise motor development into three areas: postoral control, ability to stand upright; locomotive control, ability to move around; and manual control, ability to manipulate objects (Keogh, and Sugden, 1985).

Trends in Physical Growth and Motor Development

The trends in physical growth and motor development will be discussed under the following sub-topics.

1. Physical Growth

Physical growth follows a predictable pattern. That is, growth obeys two developmental principles. These principles of development are: cephalocaudal principle, and proximodistal principle.

The cephalocaudal principle states that growth and development proceed from head (cephalo) and move downwards to the feet (candal for tail). This is why the head of a newborn is bigger and heavier than the rest of the body. All the human brain cells are there at birth. After birth, the brain cells do not divide further or regenerate.

The proximodistal principle states that growth and development proceed from the centre of the body and move outward to the periphery or the outermost parts of the body. The major internal organs of the body – the lungs, the heart, the liver are complete and functional at birth. They show very slight increases after birth. The arms and legs continue to increase until late adolescence.

Physical growth is more rapid in the first year of a child’s life. According to Durojaiye (1976), the average birth weight of the African child is 2.5 kg; and the average height is 0.5m. By the end of the first year of life, the average weight would have reached 7.5 kg (3 times) while the average height would be about 0.75m (half as much). By the end of two years, a child reaches approximately half their adult height.

A noticeable pattern in human growth is that it is characterised by spurts, plateaux, and peaks. There are periods of very rapid growth, slow growth, and rounding off. Human growth does not take place steadily. Lampl Veldhius and Johnson (1992) discovered that infants and toddlers grow in spurts, not steadily. Their research findings indicated that babies can grow as much as 0.01m in a day, and then go for days or weeks without any growth.

Between the ages of 3 years and 6 years, rapid physical growth continues. Children within this period gain on the average 0.1m in height, and 2.9 kilogrammes in weight per year (Durojaiye, 1976). Between the ages of 6 years and 12 years, growth proceeds at a very slow rate. The average annual increase in height is about 0.06m. The annual increase in weight is about 2 kg.

At puberty, the period of physical growth and development that brings to an end childhood and enables the child to achieve adult physical size, growth spurt reappears. The average age children enter puberty is 12 years. This marks the beginning of adolescence. The period of adolescence is between 12 years and 20 years. It is characterised by rapid and dramatic changes in growth.

The adolescent period is also characterised by increased growth of the internal organs of the body. There is an increase in the size and capacity of the lungs. The size of the heart doubles, and the total volume of blood in the body increases. There is a noticeable increase in the capacity of the digestive system (Berger, 1986).

2. Motor Development

Motor development follows a sequential, systematic and predictable trend. It follows a definite sequence – the cephalo-canal principle.

Motor control is achieved first in the head, then the arms, hands, upper part of the trunk, lower part of the trunk, and finally the legs and feet (Hurlock, 1972; Shirly, 1933). Thus, infants first lift their heads; then gain control of the shoulders; then sit up; then stand before they finallywalk.

Motor control also proceeds in the proximodistal direction. The child gains control of the structures nearest the centre of the body before those at the periphery. For example, the child gains control of the muscles in the arms earlier than the muscles in the fingers.

In general, motor control proceeds from gross manifestation to specific or fine control. At birth, the child has little control of the chest and the arms. However, within four months, the child can hold themselves up while face down, using their arms as props. Thereafter, the infant can sit up with support. Then, the child can hold on to an object and rollover.

These activities involve large-muscle control. They are called gross motor skills.

Activities that involve the use of small-muscle groups appear followed by gross motor skills. By 10 months of age, the child can grasp an object between their fingers and the palm. By the first year, the child is able to pick up small objects without dropping them. Activities that involve small-muscle groups are called fine motor skills. Fine motor skills are required for reaching and manipulating objects, such as in grasping, throwing, writing, catching, and using tools.

Factors Affecting Physical Growth and Motor Development

There are two major factors that influence physical growth and motor development.

They are genetic factors, and environmental factors.

· Genetic Factors

Everybody inherits a set of genes from the parents. Genes contribute significantly to physical growth and motor development. Genes determine the child’s potential for growth and development. The eventual height a child attains, the skeletal formation, the general musculature, and neural system coordination depend, to a large extent, on their inherited potential (Thomas, 1991). The rate of maturation of bodily structures and the muscles determine the rate of physical growth and motor control. The rate of maturation is known to be genetically wired. Thus, the kind of motor skills an individual develops depend on genetic potentiality.

Hormonal functioning is an aspect of genetic factor in proper functioning of the growth controlling hormonal glands is necessary for normal physical growth and motor development. Malfunctioning of growth controlling hormonal glands may lead to stunted growth or overgrowth.

· Environmental Factors

Many aspects of the environment can affect physical growth and motor development. They include nutritional status, health status, psychological or emotional state, and training/practice.

Nutritional Status

Every child requires food nutrients provided in the needed proportion for them to realise their genetic potential for physical growth and development. If there is significant lack of food nutrients, and the child is severely malnourished, physical growth and motor development will  be seriously affected. There will be delay in the appearance of important motor skills or they may fail to appear ultimately.

Health Status

Good health is a pre-condition for normal physical growth and motor development. If a child’s health is severely poor and long duration, physical growth and motor development will suffer. There may be loss in weight and reduction in growth rate. Severe ill-health can result in distortion in the growth of bones. These may lead to hampered size atmaturity of the skeleton.

Psychological or Emotional State

Findings from research studies suggest that emotional disturbance arising from repeated parental conflict or divorce, maltreatment, child abuse and neglect, overcrowding, and other negative emotion-inducing circumstances may make children loose weight without being ill. Evidence shows that children from broken and highly stressful homes manifest slower rate in physical growth and motor development.

Training/Practice

Maturation is the basis of development of motor control. However, the refinement and improvement of fine motor skills require considerable training and practice. Training and practice produce star performanceexhibited in sports and athletics such as running, jumping, throwing, catching, footballing, and others. Training and practice are most efficacious when introduced at a time the child is biologically ready for the skills.

Educational Implications of Physical Growth and Motor Development

Physical growth and motor development have some implications for the educational practice.

Firstly, physical growth affects behaviour. Behaviour in turn influences growth and development. Hence, an understanding of the patterns of physical growth of children is vital to understanding their behaviour at various stages of development.

Secondly, physical growth and motor development constitute the basis for the development of motor skills and various abilities. Hence, physical growth and motor development affects social adjustment.

Thirdly, a child’s rapidly changing physical structures in terms of height, weight, and physical appearance affect their attitude to self and others. Attitude to self and others contributes to self -concept formation. Self -concept influences school achievement.

Fourthly, vigorous play activities are predicated on well-formed physique and proper motor control. Vigorous play is a vital safety valve for built up aggressive behaviour of children. It is also a source ofsocial recognition. These are important components of healthful development.

Finally, children show extensive individual differences in physical growth rate and motor control. The teacher of children must internalize the reality that individual differences aside, the goal of development is the realisation of every child’s potential.

We considered physical growth and motor development. We noted that in addition to gaining height and weight, the body also changes in shape and structure. What we have described are the norms, that is, the averages of a large population of children. You will, in reality, observe wide differences in physical growth and motor development among the children you will encounter.

Notwithstanding wide individual differences among children in physical growth and motor development, each child’s pattern may be normal.

Each child’s pattern will reflect their unique genetic, and environmental given. Your goal, as a caregiver, is to provide a conducive environment for each child to be able to realise their potential.