Growth, development, and maturation

Growth, development, and maturation are terms used to describe changes that occur in the body starting at conception and continuing through adulthood. Growth refers to an increase in the size of the body or any of its parts. Development refers to differentiation of cells along specialized lines of function(e.g., organ systems), so it reflects the functional changes that occur with growth. Finally, maturation refers to the process of taking on adult form and becoming fully functional, and it is defined by the system or function being considered. For example, skeletal maturity refers to having a fully developed skeletal system in which all bones have completed normal growth and ossification, whereas sexual maturity refers to having a fully functional reproductive system. The state of a child’s or adolescent’s maturity can be defined by:

• Chronological age,
• Skeletal age,
• State of sexual maturation.

We will refer to the child and the adolescent. The period of life from birth to the start of adulthood is generally divided into three phases: infancy, childhood, and adolescence. Infancy is defined as the first year of life. Childhood spans the period of time between the end of infancy(the first birthday) and the beginning of adolescence and is usually divided into early childhood(preschool) and middle childhood(elementary school). The period of adolescence is more difficult to define in chronological years, because it varies in both its onset and its termination. Its onset generally is defined as the onset of puberty, when secondary sex characteristics develop and sexual reproduction becomes possible, and its termination as the completion of growth and development processes, such as attaining adult height. For most girls, adolescence ranges from 8 to 19 years for most boys from 10 to 22 years.

With the increasing popularity of youth sport and an emphasis on increasing children’s physical fitness, we must understand the physiological aspects of growth and development. Children and adolescents must not be regarded as mere miniature versions of adults. They are unique at each stage in their development. The growth and development of their bones, muscles, nerves and organs largely dictate their physiological and performance capacities. As children’s size increases, so do almost all of their functional capacities. This is true of motor ability, strength, cardiovascular and respiratory function, and aerobic and anaerobic capacity.