Movement is Nurturing (Part 2):
Movement Shapes Us
Movement during development isn’t just imperative for motor skill practice and progression; it helps to shape us as human beings. That’s to say, movement has real, physical implications on how we adapt, grow and develop into our adult forms.
The human body—including its bones and alignment—is sculpted in part by the progressive strains placed on it during movement.In Part 1, we uncovered the maturing Central Nervous System (CNS) shapes early stages of development. As the CNS matures in an infant, the child gains control of its body and begins to demonstrate purposeful movement, such as grasping a toy. But beyond this, there’s a connection between the maturation of our CNS and the physical development of our musculoskeletal (MSK) systems, and ideal movement acts as a common denominator between the two.
Ideal Movement: While everyone moves in their own unique way, the term “ideal movement” is reserved for movement that is efficient at achieving its goal, while being produced in a way that minimizes strain the body as much as possible.
Our MSK system is comprised of the muscles, bones and joints that give our bodies structure and allow them to move and do work. Growth itself has a significant effect on this system, especially as it relates to sheer size, but that’s not the only factor that contributes to its maturation. In fact, the MSK system is highly malleable, particularly in childhood; it reacts to the stresses placed upon it and changes its structure accordingly. How we move and how we load our body becomes particularly important in the first year of life and throughout our formative years! Muscle contractions and the loading of joints and ligaments that occur during any and every type of movement create stress on the bones, joints and other soft tissues. This forces them to adapt, and results in changes we see in just about every person as they grow older (e.g., reshaping of joints; the thickening of bone; the calcification of cartilage; the stiffening of ligaments; and the growth of muscle and boney projections).
Images A-C demonstrate the skeletal (A) and muscular (B-C) anatomy of the adult hip. Take the time to appreciate the complexity the region with the vast number of muscles that work across the hip to produce movement and maintain stability. During development, the physical stresses related to movement and proper muscle coordination help shape the soft-tissues as well as the bone and joint into its more stable and developed adult form.(1)
Image captured from Visible Body
The vital relationship between the CNS and the MSK systemThink back to when you were a child: As your CNS matured, so did your ability to perform more complex, weight-bearing movements, which progressively required more elaborate muscle coordination strategies. These skills were nurtured with quality movement repetition. All this in turn shaped your body into the functioning person you are today.
When CNS maturation stalls: the case of Cerebral Palsy Cerebral Palsy (CP)is a disorder that affects muscle tone, movement and coordination. CP is most often caused by an injury that occurs before or during a baby’s birth, where the child’s brain is either damaged or hasn’t had the opportunity to develop normally. For a child with CP, the injury to their brain stalls CNS maturation, which negatively effects movement development. Specifically, as they grow, children affected by CP sometimes exhibit infant-like movement patterns, similar to those found in newborns. Consequently, they also tend to retain many of the same structural properties in their bones and joints as those of babies. And so, as their bodies continue to grow, their joints remain structurally immature due to improper loading and poor motor coordination.
But what about situations where CNS maturation gets interrupted, such as in children with Cerebral Palsy? In those cases, movement quality and muscle coordination are disturbed and therefore the MSK system won’t adapt along the usual trajectory. As a consequence, the individual will go on to experience these effects in their bodily development. Alternatively, let’s look at a situation where normal movement milestones are skipped, and how that affects the body:
When an infant is placed in postures they’re incapable of doing themselves based on their level development (e.g., being made to sit upright prior to being able to do so themselves), their CNS may not be mature enough to allow their body to achieve this posture. But with a little coaxing and the assistance of an overzealous adult, the infant’s body will figure out a way to do what’s being asked of them—but all the while, calling on muscles and skeletal structures that aren’t physically ready to take on the stresses of this movement. Given any amount of repetition, this less-then-ideal posture (and its ill effects on muscles, bones and joints) can be reinforced and can ultimately affect both the child’s quality of movement as well as the structural integrity of their MSK system over time. Taken a step further, consider what seems like a simple movement to adults—walking—and the structures necessary to make this activity possible. From a developmental perspective, walkingrequires complex neuromuscular coordination. Countless motor milestones must be reached before a child is able to resist gravity, stand up and walk. However, sometimes this skill is rushed by parents, who are determined to have their child walking by a certain chronological age. Some go as far as holding their kids up and walking with them. In this scenario, however, the child’s CNS may not be mature enough to be equipped with the ideal muscle coordination strategy to execute such an advancedmovement. And so, in lieu of having the appropriate groundwork laid by the CNS, the body chooses an alternate, and generally less-than-ideal, strategy. And with repetition, this gets reinforced, and can affect not only the quality of movement but also the structural integrity of the MSK system and posture.