Motor Development Overview

These flashcards cover key concepts and findings from a lecture on motor development, infant reflexes, and postural control.

Individual constraints during reflexive and preadapted periods

Changes in body growth, muscular strength, and function of sensory systems.

Abrupt change in environmental constraint at birth

The force of gravity on the body is no longer counteracted by buoyancy from amniotic fluid.

Rhythmic stereotypies

Spontaneous rhythmic movements that are common in the first year and may indicate a pathological condition if exhibited later.

Spontaneous and reflexive movements

Both types of movements are present prenatally.

Infantile reflex not included

The swimming reflex.

Asymmetric tonic neck reflex response

If the infant's head is rotated to the right, the right arm extends while the left arm flexes.

Stepping reflex results by Thelan et al. (1984)

Adding weight to the legs decreased the number of stepping responses.

Hypothesis of disappearing stepping reflex

The stepping reflex disappears because leg muscle strength increases more quickly than leg weight.

Typical age for visual tracking development

Infant A is about 2 months old, and Infant B is about 5 months old.

Fast short-duration eye movement

Saccade.

Motor redundancy defined

Motor redundancy occurs when the degrees of freedom is greater than the number of task constraints.

Maintaining balance with center of mass

Necessary for both static and dynamic balance.

Postural control and balance development constraints

Body system developments are individual constraints for postural control and balance.

Control of head movements in infants

Infants cannot lift their heads at birth, and neck muscle weakness is a key constraint.

Direction-specific responses of one-month-old infants

Not observed, as they cannot sit independently.

Response to platform movement in FMP period

The tibialis anterior and gastrocnemius muscles both respond early.

Anticipatory postural adjustments

First observed during the FMP period.

Postural sway in development conditions

Increased postural sway in children and older adults compared to young adults.

Sway-referenced platform behavior

Proprioception is less reliable in sway-referenced conditions.

Effect of vision removal in postural sway

Increased sway in condition with no vision compared to normal conditions.

Definition of locomotion

The ability to move from place to place.

Crawling's cumulative development aspect

All infants exhibit belly crawling before hands-and-knees crawling.

Importance of pull-to-stand technique preferences

Infants initially prefer the two-leg technique.

Rate limiter for independent walking achievement

Leg muscle strength and neural aspects of dynamic balance are crucial.

New walkers’ characteristics

Flat-footed initial contact and wider base support.

Falling downward during walking

In new walkers, it refers to the center of mass accelerating downward.

Walking speed changes with age

Walking speed decreases with age after middle age.

Why older adults walk slower than young adults

Because older adults walk with a shorter step length.

Older adults’ gait characteristics

Exhibit a larger step width and greater time in double support.

Joint power during walking

Rate at which joints add energy to the body.

Grip force differences in older adults

Maximum grip force is less for older adults than for young adults.

Movement units in reaching

Describes the number of peaks in velocity during reach.

Straightness of hand trajectories improvements

Most improvement occurs from ages 1 to 7.

Preshaping in reaching context

Adjustments made to the hand before reaching to match object size and shape.

Hand opening behavior during reaching study

Young adults opened their hands wider compared to older adults.