Your little kiddo is now grown up enough to play with his friends, not at home but in the park. He has found interest in outdoor activities and enjoys soiling himself in dirt with his friends.
What you need to know
This is a sign of his consistent growth, which is giving his body strength to endure physical activities with much ease. Motivate him to take part in sports in school. Buy him things that involve playing outside home like a scooter, football, etc. So that he keeps himself active and not stuck with his fancy gadgets at home that may hinder his physical growth.