Final answer:
Increased coordination and agility in middle childhood are attributed to the steady development of muscle strength, coordination, and motor skills as children engage in various physical activities and sports.
Step-by-step explanation:
One reason for increased coordination and agility during the middle childhood years, which cover the ages of six to ten, is due to the steady development of various abilities such as agility, balance, and endurance. During this stage of physical development in middle childhood, muscle strength and coordination significantly improve, allowing movements to become more controlled and graceful. As children engage in various physical activities, including learning to ride a bicycle without training wheels, their bodies naturally adapt and enhance these vital motor skills. Additionally, children often participate in sports or other group activities which further enhance their coordination and agility. The progress they make physically is concurrent with cognitive advancements that allow them to understand rules and follow games, all contributing to enhanced physical capabilities.