Every time your baby moves, she's practicing ways to make her body act the way she wants it to.
Infants develop from top to bottom.
Head movements come first, then neck muscles begin to strengthen. Development continues on to the arms, hands, legs and feet. For example, once your baby learns to control her head and neck, she's on her way to mastering sitting. How and when a baby learns to crawl and then walk is a complicated matter. Everything in his surroundings plays a part.