An infant’s physical development is very rapid. Developmental psychologists find that how physical development in infancy and toddler. After birth, the Infant has rapid weight gain. And, he starts gaining more weight. The infant starts doing physical activity. He does his activity by moving his hands and legs. Physical development in infancy depends on neurons and nutrition.
And physical development of the infant also depends on heredity. As the physical development of the infant increases. By the way, the environment also affects its physical development. Physical development slows down after reaching its limit.
At birth, a baby’s weight is 7.5 pounds( 3.4 kg) and by age 5 months birth weight has doubled 15 pounds (6.8 kg), by age 1-year infant weight is tripled about 22 pounds(9.97 kg) by age 2 year quadrupled (X4) about 30 pounds (13.6).
A child’s overall body size increases. And two growth patterns describe body changes. They are cephalocaudal trend and proximodistal trend.
I. Ceplahocaudal Trend This trend is from head to tail. In the prenatal period, the development of the head is more rapid than in other parts of the body. At birth, the head takes up one-fourth and the legs are one-third. At 2 years, the head is for one-fifth and the legs are one-half of the total body length.
II. Proximodistal Trend This Trend is near to far. In the prenatal period, the first growth of the head, chest, and trunk then arms and legs during infancy and childhood.
In physical development, at birth, the development of the brain is mostly complete than other parts of the body. The development of the brain is dependent on neurons, the cerebral cortex, and brain lateralization.
I. The Development of Neurons Humans has 100 to 200 billion neurons. These neurons store and transmit information. If the number of neurons is less, then physical development slows down. And Infants’ neurons grow very fast.
II. The Development of Cerebral Cortex The cerebral cortex is the largest structure of the brain and this area is 85% of the brain’s weight. It is containing the largest number of neurons and synapses. And, most neurons are made in the cerebral cortex. So, the cerebral cortex also has its own special importance in physical development. Due to having more neurons in the cerebral cortex, the brain also develops more.
III. The Brain Lateralization The cerebral cortex has two hemispheres. They are the left hemisphere and right hemisphere. These two hemispheres are responsible for brain lateralization.
In the infancy and toddler stage, physical development and growth are very complex processes and many factors also influence physical growth. These factors are heredity, nutrition, and malnutrition.
I. Heredity Studies (identical and fraternal twins) proved that heredity plays an important role in physical growth.
II. Nutrition The first two years of a child’s life need nutrition because the brain and body are growing rapidly. For infancy, breastfeeding is most important than bottle feeding because breastfeeding has much nutrition.
III. Malnutrition According to WHO, in the world, 27 % of children suffer from malnutrition before age 5. Malnutrition occurs when the diet does not contain nutrients and it is related to poor nutrition.