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Principles of Normal Development

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By Allison Wallis, P.T.

Communication Skill Builders, Inc.

The word “normal” can be misleading – every person has a unique combination of strong and weak skills. The athlete may have excellent coordination but poor speech and language skills, while the chess player may have strong thinking skills but be unable to catch a ball. But they are both “normally” developed.

Still, babies develop in similar ways. Here are some of the general principles and theories of infant development.

Head to Toe

Babies develop movement or motor skills in a head-to-toe direction. They are born curled into the fetal position and immediately begin trying to lift heir head to look around. The first movements your baby can control are those of the head and eyes. Next, your baby develops the ability to bring the hands together while in a back lying position.

Your baby has active control of the mid-to lower trunk when rolling. Lower trunk control develops when your baby brings the feet to the mouth when lying face up. Pelvic (hip) stability can be seen when your baby learns to sit alone. Hip and knee control are achieved when your baby crawls. Overall head-to-toe control appears when the baby takes the first steps, even though it takes three years for the child to develop complete control in standing postures.

Proximal to Distal

Proximal means close to the body. Distal means away from the body. The shoulder is proximal; the hand is distal. Babies must develop proximal stability before doing intricate hand and foot movements. Trunk control is needed for balance, to serve as the base of support – before working on fine hand skills, your baby must be able to sit well.


During the first year, your baby rapidly develops gross control of large motions. Your baby changes from a newborn without head control to a child learning to walk. This intricate and systematic process leads to head and then trunk control, shoulder stability, pelvic stability, hip control, knee control, and finally ankle and foot reactions.

From age 1 to 2, your child’s focus changes to the fine skills – those that involve manual dexterity and problem solving. Your child sits for long periods working with blocks, puzzles, and clothing, learns to eat without help, and loves to explore.

From age 2 to 3, skills are refined even more. Your child learns to speak in sentences, uses eating utensils, learns the skills necessary for writing, and begins to understand learning concepts.

These finest skills must be built on a solid foundation of gross skills. Your child needs proximal trunk control before reaching out to explore with refined hand, finger, and eye movements. For example, a child with poor trunk balance won’t be able to sit well at a desk, so schoolwork may suffer.

A team of specialists can help if your child’s development is delayed. The physical therapist deals with gross motor skills. The occupational therapist works with fine and finest visual and eye-hand skills. The speech-language pathologist works with fine to finest speech, language, and oral motor skills.

Symmetry vs. Asymmetry

Symmetry means equal. Asymmetry means unequal, as when one side of the body works better than the other. Infants are born in an asymmetrical position because of early primitive reflexes and the lack of muscle power and control. By about age 4 months, the infant begins to show symmetry in supported positions.

Soon, your baby begins controlling asymmetrical movements. Kicking while lying face up comes first. At first, both legs kick in a random reflex. Then your baby learns to draw both legs toward the tummy while reaching for the thighs.

Next is hands to knees, hands to feet, and finally feet to mouth. At the same time, your baby learns to kick alternate legs, enjoying the movement and the sounds of feet banging onto the floor.

Reflexive, Automatic, Voluntary Movement

The newborn’s central nervous system is immature, so your baby’s movements are jerky and random. At first, if one leg bends the other bends with it. If one hand is fisted, the other will also be fisted.

These early movements are flexes – preprogrammed responses to outside influences. For about the first four months, many reflexes help protect the infant. If  the feet are touched, they recoil towards the body. If the cheek is stroked, your baby turns in hope of finding food.

Automatic reactions appear at about 4 months. These help your baby stay balanced and vertical. Automatic reactions also move the limbs away from the body to protect the face in a fall.

Voluntary movements – those done deliberately – are at the highest level of control. Think of the infant who has just learned to sit. The baby sees a toy but doesn’t have the coordination to move out of the sitting position. Soon, though, the child can decide to get the toy, get onto hands and knees, crawl to the toy, resume sitting, and play. What control!

Stability vs. Mobility

Newborns can’t move or control their bodies very well. Muscular length and joint mobility increases as the infant begins to stretch and use the muscles.

Working the back muscles helps your baby work out of the fetal position. The muscles on the front of the body lengthen as your child pushes up from a tummy lying position. The muscles on the back of the body and legs lengthen when your baby’s feet are brought to the mouth in the back lying position.

Once your baby has some mobility, the next job is to gain stability by learning to balance the muscles on the front and back of the body. A stable position supplies a base from which to move and a place to return to – a home base – after moving or losing balance.

Active mobility is the next goal. With a stable trunk and pelvis, your baby can reach out without losing balance.

Weight bearing precedes movement into space

Your baby will put weight on the arms and legs to prepare the limbs for more advanced movements. From a tummy lying position, your baby first pushes up onto both arms and hands, and then learns to shift weight from front to back and then side to side. The shoulders grow stronger and more stable; soon, your baby can prop up on one arm while reaching out with the other.

Two steps forward, one step back

Development seems like a staircase. But it’s really more like a rope, since the many skills and movements are intertwined. That’s why you need to understand your child’s earlier development and potential for future development.

Your baby can’t concentrate on all areas of development at the same time. Instead, the baby will concentrate on one area and appear to lose skills in another. Children often stop talking for a few weeks when they first learn to walk.

Your baby might also return to more primitive patterns of movement when a skill becomes difficult or if the baby’s balance is challenged. When first learning to sit, your baby’s arms will be held out at the sides and the shoulders will be elevated for greater stability. But when your baby is on the floor lying face up, the shoulders are relaxed and the arms reach forward into space with control.


Normal development is never “normal.” A unique set of genetic and environmental forces guides each child’s development. Plus, each child has a unique personality and way of learning.

Try not to compare your child with other children – development means growing, not racing. It’s much better to compare your ‘yesterday” child with your “today” child, and see the changes your child has accomplished. We’re all “normal,” and we’re all unique!

Ask Dr. Susan