17.1: Physical Growth

Learning Objectives

1. Describe typical physical growth patterns and growth spurts during middle childhood.
2. Define the role of human growth hormone (HGH) in child development.

Middle childhood (often referred to as the school-age years) spans the years between early childhood and adolescence, generally from ages 6 to 11, or until the onset of puberty. During this time, children come in all shapes and sizes—varying in height, weight, abilities, and developmental timelines. While general patterns of physical development exist, individual differences are common and expected.

Growth Patterns and Spurts

Physical growth during middle childhood is usually described as slow and steady, with children gaining approximately 5 to 7 pounds and growing about 2 inches per year (Centers for Disease Control and Prevention [CDC], 2022). However, this steady growth can be misleading. Growth does not occur at a uniform rate every day. Instead, research suggests that children often grow in spurts, sometimes experiencing significant increases in height within just 24 hours, followed by periods of little or no growth (Adolph & Hoch, 2019). These short bursts of rapid growth may be more common during certain seasons; many children grow fastest during spring or summer, although patterns can vary individually (Pérez-Escamilla et al., 2021).

In addition to increasing in height and weight, children in middle childhood tend to slim down, gaining muscle mass and strength as baby fat decreases. Their bodies become more proportionate, as the extremities grow faster than the trunk, resulting in a more adult-like appearance. Strengthening muscles and lengthening bones encourages children to engage in strenuous physical activity, such as sports, biking, or climbing. Their increased stamina and motor skills enable longer and more coordinated play, which is crucial for overall health and well-being.

Figure \(\PageIndex{1}\): Stature for age and weight for age percentiles of boys and girls. Images by the CDC is in the public domain.

Differences Between Boys and Girls

As children approach late middle childhood, growth accelerates again as they prepare to enter adolescence and the associated hormonal changes of puberty. This prepubescent growth spurt typically begins around age 9 or 10 for girls and closer to age 11 for boys, resulting in noticeable differences in physical development between the sexes. This is why girls may temporarily be taller or more physically developed than boys of the same age. The earlier onset of puberty-related growth in girls is linked to the earlier rise in estrogen, while boys catch up and often surpass girls in height after entering puberty, due to a later and more prolonged testosterone-driven growth period (Rogol & Clark, 2008).

Growing Pains

As bones lengthen and broaden during this time, and as children engage in more physical activity, many report growing pains, particularly in the evening or at night. These pains are often described as an aching or throbbing in the legs, especially in the shins, calves, or behind the knees, but also sometimes in the arms. While not directly caused by growth itself, these pains are thought to be related to the increased physical demands placed on growing muscles and joints (Hashkes & Uziel, 2011).

Growing pains are common and usually harmless; however, persistent or severe pain should be evaluated to rule out other potential conditions. There are simple and effective ways to help soothe growing pains, such as gentle massaging or stretching right before bed, using a warm compress, or applying a heating pad.

Human Growth Hormone (HGH)

A key player in physical development is the human growth hormone (HGH), a peptide hormone secreted by the pituitary gland that stimulates bone and tissue growth. HGH is essential for normal physical development in childhood. In some cases, children may be diagnosed with growth hormone deficiency (GHD), a medical condition in which the body does not produce enough HGH to support normal growth. This can lead to shorter stature and delayed physical development if left untreated.

Treatment for GHD typically involves daily injections of synthetic HGH, which has been shown to significantly increase growth rates and help children achieve a more typical adult height when started early (Grimberg et al., 2016). However, HGH treatment is not without controversy, especially when used in children without a medical deficiency simply to increase final height. In such cases, the benefits may not outweigh the costs and potential risks.

References, Contributors and Attributions

Adolph, K. E., & Hoch, J. E. (2019). Motor development: Embodied, embedded, enculturated, and enabling. Annual Review of Psychology, 70, 141–164. https://doi.org/10.1146/annurev-psych-010418-102836

Centers for Disease Control and Prevention. (2022). Growth charts. https://www.cdc.gov/growthcharts/

Grimberg, A., DiVall, S. A., Polychronakos, C., Allen, D. B., Cohen, L. E., Quintos, J. B., ... & Drug and Therapeutics Committee and Ethics Committee of the Pediatric Endocrine Society. (2016). Guidelines for growth hormone and insulin-like growth factor-I treatment in children and adolescents: Growth hormone deficiency, idiopathic short stature, and primary insulin-like growth factor-I deficiency. Hormone Research in Paediatrics, 86(6), 361–397. https://doi.org/10.1159/000452150

Hashkes, P. J., & Uziel, Y. (2011). Growing pains in children. In M. Petty & R. Cassidy (Eds.), Textbook of Pediatric Rheumatology (6th ed., pp. 670–674). Elsevier.

Pérez-Escamilla, R., Bermudez, O. I., Buccini, G., Kumanyika, S., Lutter, C. K., Monsivais, P., & Victora, C. G. (2021). Nutrition disparities and the global burden of malnutrition. BMJ, 372, n246. https://doi.org/10.1136/bmj.n246

Rogol, A. D., & Clark, P. A. (2008). Growth and pubertal development in children and adolescents: Effects of diet and physical activity. The American Journal of Clinical Nutrition, 88(5), 1583S–1587S. https://doi.org/10.1093/ajcn/88.5.1583S