Final answer:
During middle childhood, body growth is gradual with an average yearly increase of 7 lbs. in weight and 2.3 inches in height. The stage is marked by the improvement in muscle strength and coordination. An adolescent growth spurt may begin during pre-adolescence, leading to more pronounced changes in body composition and sexual dimorphism.
Step-by-step explanation:
The period of middle childhood is characterized by slow and steady physical growth, including an average increase of about 3.2 kg (7 lb.) in weight and 5.8 cm (2.3 in.) in height per year. This stage extends from around ages six to ten and is marked by important developments such as improved muscle strength, coordination, and the growth of a child's remaining deciduous dentition.
During pre-adolescence, some children may begin an adolescent growth spurt (AGS), although the majority of rapid growth happens during adolescence, when changes in body composition and sexual dimorphism become apparent.
In middle childhood, the differences in size between sexes are minimal, but as they approach adolescence, there are noticeable changes in body composition as males and females experience growth in different areas, such as the chest and hips respectively. The AGS includes significant changes in muscle, bones, and body fat, particularly for females. Furthermore, a common milestone in this stage of development is the loss of baby teeth, as seen in the happy six-year-old who just lost their left lower central incisor.
Overall, the growth pattern of children in middle childhood is gradual and sets the foundation for the more rapid and diverse changes in body size and composition that occur during adolescence.