The outdoors can be the best place for children to practice and master emerging physical skills. It is in the outdoors that children can fully and freely experience motor skills like running, leaping, and jumping. It is also the most appropriate area for the practice of ball-handling skills, like throwing, catching, and striking. And children can perform other such manipulative skills as pushing a swing, pulling a wagon, and lifting and carrying movable objects. 

Additionally, it is in the outdoors that children are likely to burn the most calories, which helps prevent obesity, a heart disease risk factor that has doubled in the past decade. Studies showing that as many as half of American children are not getting enough exercise. The outside is also important because the outdoor light stimulates the pineal gland, the part of the brain that regulates the "biological clock," is vital to the immune system, and makes us feel happier.

The outdoors has something more to offer than just physical benefits. Cognitive and social/emotional development are impacted, too. Outside, children are more likely to invent games. As they do, they're able to express themselves and learn about the world in their own way. They feel safe and in control, which promotes autonomy, decision-making, and organizational skills. Inventing rules for games promote an understanding of why rules are necessary. Although the children are only playing to have fun, they're learning communication skills and vocabulary, number relationships, and social customs.