After 4 months of age, the most significant thing for babies is the improvement of waist strength, when parents hold their babies, they can straighten the waist, hard! Some parents may ask, how can I make my baby’s waist strength play better? 1, prepare a beach ball or yoga ball for the baby, let the baby lie on it, parents hold the baby’s crotch, move the baby’s body back and forth, exercise the back strength stretch; conversely, the baby lying on the yoga ball, exercise the child’s abdominal strength stretch; 2, let the baby lie on a blanket, and then help him from the supine or prone position turned to the side. Pull up one side of the blanket and lift it upward to help the baby turn from supine to side, or you can pull up the blanket and gently shake the baby back and forth to let him exercise how to swing the body and exercise the waist and abdominal strength; 3.Let the baby lie flat, and the parents turn the child’s leg on one side to the other side of the body to give the child a feeling of strength to turn around and exercise the child’s waist and leg strength; 4.You can let the baby lie on his back, and the parents hold Baby’s two wrists, slowly pull the baby from the supine position into a sitting position, and then gently put the baby back down into the supine position, so back and forth repeatedly do sit up and lay down the game, you can make the baby’s neck and back muscles and abdominal muscles to exercise. If the baby’s hand already has a good grip, parents can also put the thumb in the baby’s hand, let the baby hold tightly for the above games of sit up and lie down. When training in this way, pay attention to whether the baby’s grip is strong enough to complete the entire game.