Baby learns to do a push up on the stairs. This strengthens her arms for hands and knees crawling.
BABY STRENGTH AND MOTOR SKILL DEVELOPMENT
Babies gain strength in their muscles through learning motor skills. This means that they do not need to do repetitive exercises as we do them in a gym. The actions of learning each motor skill develops much strength. Kicking, for example, is one of the first motor skills that baby learns and it develops quite a bit of strength in the muscles of the legs. The action of lifting the legs and moving them (kicking) on her own requires strength. As baby grows and gains weight her limbs become bigger and heavier. This in turn builds even more strength. No need to put more weights on the machine at the gym, baby’s changes in her body size increase the challenge for her muscles.
In tummy-time, the action of lifting the head strengthens her head and neck muscles. Baby’s head is one of the heaviest parts of her body, so through practice of this motor skill her back and neck muscles become very strong and prepare her for sitting with excellent baby posture. As baby learns to move her own body weight around she gains a tremendous amount of strength.
BABY CRAWLING AND BABY ARM STRENGTH
Baby’s shoulders, hands, and arms needs to develop strength for the motor skill of crawling in the hands and knees position. This strength develops from the mini-milestone of pushing. Adults build arm, hand, and shoulder strength from push-ups. Babies do a version of a push up when they push their hands into the floor in tummy time or when they learn to push the hand down on a stair. The seven month old baby in the above photo is strengthening her arms as she pushes down into the stairs while learning the skill of climbing.
When a baby learns to lift her pelvis and pull her knees under her, yet remains with her forearms on the floor, her back will “cave in” or have a large arch to it. Once she strengthens the muscles of her arms and shoulders she can push down into the floor and get into the hands and knees crawling position. Now her back is arched less. This crawling position will build even more strength for baby as she supports all of her weight on only her hands and knees. She may need to pull up to this position and not move for a while. She has to develop strength in this position before she can move. Over the next several weeks, hands and knees crawling develops much strength in her arm and legs muscles which prepare her for the motor skill of standing up.