Motor development

What is Motor Development?

— Acquiring motor patterns and skills with process of modification

– Neuromuscular maturation

– The physical growth and behavioural characteristics of the child

– The tempo of this process

– physical growth, biological maturation and behavioural development

– Residual effects of prior movement experiences; and the new movement experiences

—- But doesn’t happen in isolation to other developmental trajectories!

The Neural Motor System

1. Foundations of the Neural System

   • Neural Tube Origin: Development begins with the proliferation and branching of neurons from the neural tube in utero.

   • Neuromuscular Maturation: The system relies on the maturation of both the central nervous system and the neuromuscular systems to coordinate movement.

   • Sensory-Motor Integration: Sensory feedback is critical for guiding motor development and allowing for the adaptation of movements to the environment.

2. First 18 months motor development moves at astounding rate

Infant learns to:

– balance the head

– reach and grasp,

– sit

– crawl and walk

Postural control improves rapidly during this period.

Aligns with a rapid neurological changes / development of neurological systems eg CST

1. Theories Governing the Neural System

1. Motor behaviour is not primarily reflexive

2. Cortical/ subcortical modification see even in fetus

3. Motor behaviour starts with spontaneous patterned activity

• Neural Maturation Theory:

  • This perspective emphasizes genetic factors as the primary driver. Predetermined – genetic driven – self-limited time cycle

  • It suggests that development follows a predetermined head-to-toe sequence based on the maturation of the brain- Cephalocaudal and central-to-distal

  • Increasing cortical control over lower reflexes

  • A certain amount of neural maturation must take place before any function can be modified by specific stimulation

• Dynamic system theory: This theory focuses on the interaction between the child and their environment, suggesting that motor skills are self-organizing and spontaneous.

  • Development a dynamic system

  • Self-organising process - responsive

  • ‘How can a timetable of motor solutions be encoded in the brain or in the genes?’

• Neuronal Group Selection Theory (NGST): This integrates both genetic predisposition and environmental influences. It explains how neural pathways are selected and strengthened through experience, leading to varied and adaptable movement patterns.

  • Variation present in all development parameters

  • Neuronal cells and gross primary connectivity – genetic

  • But endless possibilities – dynamic epigenetics, cell division, migration, cell death

  • Selection of afferent info – experience and behaviour

  • Not exclusive genetic nor environment dictation ‘Complex intertwining of information from genes and environment’

Prenatal Motor Milestones

• Inception ($Day~20$ / $Week~5$): Motor development does not start at birth but begins shortly after conception while in utero.

• Early Spontaneous Movement: Early reflexive and spontaneous movements emerge as the neural tube branches and neurons begin forming functional connections.

• Anticipatory Patterns ($Week~22$): By the $22nd$ week of gestation, the fetus exhibits anticipatory motor patterns, which are the precursors to reaching and grasping behaviors seen after birth.

Postnatal Motor Development Milestones ($0-18$ Months)

1. Early Infancy ($0-3$ Months)

   • Characterized by significant dependence and fetal-like positioning.

   • Movements are primarily reflexive (e.g., rooting, grasping) and occur in response to internal stimuli like hunger.

2. Emerging Postural Control ($3-6$ Months)

   • Development of head and trunk control becomes evident.

   • Infants begin to roll over and use both hands to reach for and grasp objects.

3. Developing Mobility ($6-9$ Months)

   • Achievement of sitting with support as trunk control robustly increases.

   • Initiation of crawling or bottom shuffling, which allows the infant to begin exploring their immediate surroundings.

4. Transition to Upright Movement ($9-12$ Months)

   • Movement toward standing and "cruising" (walking while holding onto furniture).

   • Integration of sensory motor responses improves balance and coordination.

5. Independent Mobility ($12-18$ Months)

   • Mastering the ability to lift the head, gain full postural control, and walk independently.

   • Movement becomes the primary tool for environmental exploration and interaction.

Theoretical and Clinical Considerations

• Evolutionary Context: Unlike other mammals, humans are born highly dependent due to the large size of the brain relative to the human pelvis; thus, much of motor development is displaced to the postnatal period.

• Horizontal and Vertical Influence: Motor skills are acquired in a sequence where skills learned in one posture (horizontal, like rolling) directly influence and support skills in subsequent postures (vertical, like standing).

• Cognitive Link: Motor and cognitive systems are digitally integrated. Early motor exploration (ages $2-4$) is essential for developing the cognitive skills required to understand and interact with objects.

• Qualitative Assessment: When evaluating motor development, clinicians look beyond just "ticking boxes" for milestones. They assess qualitative factors such as movement symmetry, muscle control strength, and the effectiveness of exploration.