Children’s Developmental Process, Assessment Example

Locomotion is a phenomenon which develops gradually in human beings and other mammalian species until complete spatial and environmental awareness, as well as the sense of balance are achieved. From a tottering individual in the early stages of life, a remarkable transformation takes place as one grows older. There are specific chronological changes and steps through which each person has to go through from infancy to early childhood until complete equilibrium and control of limb movements are achieved. Biologists have for long attributed the phenomena of postural control and coordination of body movements to neuronal maturation and development of the brain (Clark & Whitall, ). But the phenomenon may not be as simple as it seems as multiple factors are involved in the development of the locomotor ability as it involves a dynamic interplay between biological forces and the environment. The dynamical systems theory has been developed to provide an explanation for the complex interaction which takes place between organismic, task and environmental forces which enable a child to gradually attain well coordinated locomotor ability and postural control (Langendorfer, ).

The successive stages of locomotor development in a growing child are initially manifested as crawling on the belly followed by creeping movement in which hands and feet start playing a role. This is followed by the child attaining an upright position in which the first tentative steps of walking are taken. Once walking has been mastered it leads to the later stages of running, galloping, jumping, hopping and skipping movements with successively increasing levels of intricacy which require complex interplay and coordination between the involved bones, muscles and their neuronal control. The abovementioned skills are attained at about seven years of age in a child (Clark & Whitall,). The attainment of the fundamental form of upright bipedal locomotion is an important landmark which leads to the development of further locomotor skills. The descriptive maturational perspective which was formerly associated with the development of the gait forms observed in human locomotion was too simplistic in explanation of the phenomenon as a mere function of the development and maturation of brain, leading to the expression of complex locomotor behaviors. Clark and Whitall are of the opinion that the maturational perspective was based just on the observational studies of motor skills in infants and growing children. The authors believe that there is still paucity of evidence to support the fact that specific human behaviors emerge due to changes or maturation activities of the central nervous system (CNS). Similarly, there is no proof that there exist central pattern generators (CPGs) for the coordination of activities like walking, running, hopping and other locomotor skills. Moreover it would be impossible to hardwire multifarious CPGs into the brain for every other action as it would compromise the efficiency of the organ itself. If such CPGs are believed to exist, there is no explanation for the order of occurrence of motor skills which follows a uniform pattern i.e. individual CPGs would have altered the appearance of the locomotor skills in different individuals. The wide variety of motor skills that are exhibited in humans would have also needed a plethora of neural prescriptions to control the various muscles and bones and their compilation, storage and continuous upgradation would have put tremendous load on the brain. This particular problem has been labeled as the ‘degrees of freedom’ problem by the authors. By highlighting these issues with the descriptive maturational perspective of explaining locomotion in humans the authors have prepared ground for the validity of the ‘dynamical systems perspective’, which they feel can speculate about the complex phenomenon of the developmental locomotor skills and the reasons behind them in a better manner.

The dynamical systems perspective merges various aspects of biology, nonequilibrium thermodynamics and complex systems theory which interact in a complex manner to form a basis for movement coordination and control. The collective dynamical properties of muscle collectives are actually responsible for the body movements resulting in locomotor behavior. Movement is the net effect of internal variables which include limb mass, muscular stiffness and energy as well as external variables which include gravity and other forces acting upon the body (Clark & Whitall,). From a dynamical perspective each challenge which the body encounters in its requirement to move is viewed as a ‘solution’ or a source of information which is to be exploited, rather than viewing it as a ‘problem’ which would have been the case if prescriptive neuronal control was behind the movement which followed the challenge. It is actually a comprehensive coordinated structure involving a number of muscles, nerves and bones under the influence of various external and internal forces which represents a functional unit for movement as viewed under the light of dynamical systems perspective. Coordinative structures (CS) are constrained units where the relationship between the participating muscles result in reduced choices of degrees of freedom within the CNS and are made up of neuromuscular units which undergo temporary organizational coherence in order to achieve a specific function. Speech, handwriting, two-handed movements and posture are the examples of such organizational coherence.

In locomotion, the muscles of a particular limb may act as an intralimbic coordinative structure when a specific movement of that limb is the required action and muscles in two limbs e.g. in both legs act as another interlimb coordinative structure when a relational movement of the two legs is the required action. Walking, running and skipping are examples of interlimb coordinative structure in which the phasing is such that one leg is 50% out of phase with the other. One leg is undergoing a different movement as compared to the other in this sort of interlimb coordination. This form of movement is a symmetrical gait with 50:50 phasing. On the other hand, galloping and hopping are examples of asymmetric gait in which the leading limb begins its cycle 35% and 45% of the way respectively through the cycle of the other limb and therefore exhibit a pattern of 65:35 or75:25 phasing in galloping, and 55:45 or 60:40 phasing in hopping. Skipping, the final fundamental motor skill involves a combination of symmetric and asymmetric gaits in which the movement between the limbs is symmetric and within a single limb it is asymmetric because each leg performs a walking and hopping motion before alternating to the other limb. The evidence for these limb movements to be coordinative structures and the motor skills to be constrained in character is provided by the dynamical theory of interlimb coordination through a model  of coupled ensembles of nonlinear, limit cycle oscillators (Clark & Whitall,). This model is characterized by properties of entrainment, phase locking and structural stability. Entrainment is the interaction between two or more nonlinear oscillators, phase locking allows for certain phase modes to be more stable and structural stability allow it to return to a stable mode on being perturbed. This suggests ample proof of the limb organizational and functional status to be an organized as a coordinative structure free from dependence on any CNS prescription.

The development of motor activities in children might differ due to external constraints and environmental factors as well as with time, sex and age. In infants, the first attempts at walking involved a digitigrade (toe-heel) pattern at the onset of walking activity wherein the toe or the sole touched the ground earlier than the heel. With the passage of time and consistent walking activity, gradually the walking pattern acquired a plantigrade (heel-toe) character in which the heel was placed earlier than the toe. Similarly early running characteristics at the commencement of this activity in young children were characterized by a stiff pattern, shorter stride with more dependence on a wider base for support and negligible arm movement. However, with maturity running became more fluid in character with increase in stride, less requirement for a base and alternating movement of arms and legs.

Numerous studies have been carried out to observe the influence of external factors on the development of motor skills. When adults and children were asked to either throw balls at an object with full force or at a specific target marked for the throw, their motor performance differed according to the variability of the tasks set forth before them and also on the basis of their age and sex (Langendorfer). This suggests that organismic, task and environmental factors did influence developmental change in motor skill and performance. In another longitudinal study carried out on children from their kindergarten years to the seventh grade, it was observed that boys met the predicted targets for their horizontal ball throwing speeds over the years while the girls lagged behind (Halverson et al, 1982). Boys who had exclusively participated in ball throwing games such as league softball and baseball attained better speeds as compared to their counterparts. Environmental, organismic and task related factors were therefore instrumental in eliciting the variability in the attainment of motor skills in the participants of this longitudinal study.  This shows that some children do remain ‘stuck’ at primitive levels of motor performance relative to others because they have not been exposed to the demands for specific tasks which might test their motor skills. Moreover age and sex exert a vital influence on the capability for acquiring or not acquiring certain motor skills.

Works Cited

Clark, J.E. & Whitall, J. Changing Patterns of Locomotion: From Walking to Skipping

Halverson, L.E., Roberton, M.A. & Langendorfer, S., Development of the Overarm Throw: Movement and Ball velocity Changes by Seventh Grade, Research Quarterly for Exercise and Sport, Vol. 53, No.3, pp. 198-205. 1982.

Langendorfer, S., Motor-task Goal as a Constraint on Developmental Status, Advance in Motor development research