Week 3: Early Motor Development

Question 1

Describe infants’ movements (3 points)

Answer 1

• Newborn movements often seem to be undirected and without purpose. They often kick their legs whilst lying on their backs.
• Other times they move in a specific way every time they are touched, such as grabbing your finger when you touch their palm.
• These seemingly random infant movements have an important relationship with intentional movements that occur later in life. After the first few months the infant will begin to attain certain motor milestones, which are the foundational building blocks of movement skills, such as locomotion, reaching and upright posture.

Question 2

List the types of movement that occur in infancy (3 points)

Answer 2

• Newborn movements can be classified into two types of movements:
  1. Spontaneous movment
  2. Reflexive movements

Question 3

Describe spontaneous movements (6 points)

Answer 3

• Spontaneous: movements not caused by known external stimuli. It is thought these movements are building blocks
  
  • Examples include: Spontaneous arm movements (resemble reaching) and Spontaneous kicking (resembles adult walking).
  • When infants are on their backs they will often spontaneously thrusts their legs.
  • Research by Ester Thelan and colleagues in the 1980s and 1990s observed that the kicking was not random but rhythmical, and the kicks had a coordinated pattern. The ankle, knee and hip joints moved cooperatively with each other, and not independently.
  • The coordination of these kicks also resembles the positioning and timing of an adult walking step and even the pattern of muscle use in the supine kicking is coordinated.
  • Although they are similar, they are not identical, with infants moving joints in unison rather than in sequence and during muscle activation the co-contract (flex and extend at same time). However, by end of their first year they are beginning to move hip, knee and ankle sequentially.

Question 4

Describe reflexive movements (6 points)

Answer 4

• Reflexive: stereotypical responses elicited by specific external stimuli. An infantile reflex is an involuntary, stereotypical movement response to a specific stimulus
• The term refers specifically to such responses seen only during infancy.
• There are three types of infantile reflex:
  
  • Primitive: involuntary responses usually mediated by lower brain center eg. newborn infant grasps object placed in hand. The primitive reflexes start to weaken or modify after 2 weeks.
  • Locomotive: appear from birth to about 4 months and involve crawling, stepping and swimming reflex.
  • Postural: these reflexes appear at around 2 months to about a year and help the infant maintain posture.

Question 5

Describe motor milestones (9 points)

Answer 5

• Motor milestones are fundamental motor skills, the attainment of which is associated with the acquisition of later voluntary movements.
• The order in which an infant attains these milestones is relatively consistent, although the timing differs among individuals.
• Each skill is associated with a preceding milestone. For example, to walk you must be able to stand; to stand you must be able to hold your trunk upright; and to hold your trunk upright, you must be able to hold your head erect.
• Individual infants vary in the time at which they reach a motor milestone but they acquire these rudimentary skills in a relatively consistent sequence.
• The progressive pattern of skill acquisition can be related to predictable changes in individual constraints that occur in typically developing infants. These include:
  
  • maturation of the central nervous system
  • development of muscular strength and endurance
  • development of posture and balance
  • improvement of sensory processing

Question 6

Describe the Constraints and the Attainment of Motor Milestones (2 points)

Answer 6

• For an infant to exhibit a certain motor skill, they need to develop a certain system to a certain level. For example, in order for an infant to lift their head whilst lying on their belly, the infant requires sufficient strength in their neck and shoulders.
• So because the different systems advance earlier in some infants than in others, the rate of achievement of motor milestones varies.

Question 7

Describe the relationship between Motor Milestones and Atypical Development (4 points)

Answer 7

• Due to their sequential nature, motor milestones may provide clues for trained professionals about an infant’s neurological health.
• So delays in motor milestones may lead to delays in the attainment of fundamental motor skills, such as walking, and activities of daily living, such as eating.
• Because infant mobility appears to be important to early development, any condition that delays or impedes infant mobility may negatively affect cognitive development. Motor development and early movement influence both social and cognitive development.
• Therefore, delayed acquisition of motor skills can have a far more profound effect than simply the inability to move; it can influence the entire developmental process, leading to greater cognitive disabilities than would exist if the same child had movement opportunities.