Pushing Up: 4 to 5 months
After your newborn has learned to steady her head, she'll begin working on push-ups. She'll struggle to raise herself on bent elbows and later to fully extended arms. "Babies spend the first six months of life gaining control of their posture, which sets the stage for virtually all other movements, including reaching and grasping," says Carl Gabbard, Ph.D., author of Lifelong Motor Development (Allyn & Bacon, 3rd ed.,1999) and director of the motor-development laboratory in the department of health and kinesiology at Texas A&M University, in College Station.
Shifting her weight from side to side, your baby will develop arm strength and coordinate her shoulder muscles. This will eventually enable her to reach overhead and diagonally as well as hold her arms up in the air. With a stable upper body, she will no longer need her hands to support herself, leaving them free to explore. Your infant is also refining head control by holding her head off the floor and turning it from side to side.
Skill builder: Place your baby belly-down on the floor for short, frequent practice sessions throughout the day (not at naptimes or bedtime, however, because of the risk of SIDS).