© 2007 McGraw-Hill Higher Education. All rights reserved. Voluntary Movements of Infancy Chapter 10.

© 2007 McGraw-Hill Higher Education. All rights reserved.

Voluntary Movements of Infancy

Chapter 10


Objectives

• List and categorize the voluntary movements of infancy

• Describe the development of head control during infancy

• Describe the development of general body control during infancy


Objectives

• Describe the development of prone locomotion during infancy

• Describe the development of upright locomotion during infancy

• Describe the development of reaching, grasping, and releasing during infancy


“Voluntary movement is the ultimate expression in the striated muscle of the integrated effects of a host of cortical and subcortical facilitory and inhibitory influences”


The rate of acquisition for all voluntary

movements during infancy may vary


Categorizing the Movements

Voluntary movement groupsStability

Head control, upright postureLocomotion

Creeping, crawling, walkingManipulation

Reaching, grasping, releasing


Categorizing the Movements

Cephalocaudal pattern of developmentHead controlUpper body controlLower body control


Stability ~ Head Control

Voluntary movements begin at the head Milestone: infant raises head while prone

Accomplished by 3 months of age

Infant will then push the chest up with arms Raise head in supine position

Accomplished by 5 months of age


Stability ~ Head Control

Minimal voluntary control of the head

Elevates head when prone with effort

Positions head from left to right or right to left when prone

Elevates head when supine


Stability ~ Body Control

Chest elevation Segmented rolling back to front

(visa versa) Crawling Ability to maintain upright posture

frees the hands and arms for reaching and grasping


Voluntary Controlof the Body

3 months: tries to roll from supine to prone position; maintains sitting position when assisted

5 months: sits when holding external supporting object



6 months: rolls from supine to prone position; maintains standing positionwhen assisted

7 months: achieves sitting position from prone to supine position



8 months: sits alone; rolls from prone to supine position

9-10 months: pulls self to standing position, briefly maintains stand whileholding external supporting object

12 months: stand unassisted


Study on Infant’s Ability to Self-sit Phillipe Rochat (1992)(Emery University) Studied the impact of an infant’s ability to self-sit on

the development of early eye-hand coordination Half were able to sit on own Half were not able to sit on own Infants presented with display in seated, reclined,

prone and supine positions


Rochat’s Key Findings

Half of the infants were unable to sit on their own Sitters were more accurate in their reach than non-sitters All infants were more successful in the accuracy of their

reach when supine versus sitting Non-sitters used two hands to reach more often than sitters Sitters reached more with one hand in all positions Non-sitters used one hand only when seated Overall, infants’ ability to sit appears to influence the use of

hands in reaching activities


Locomotion ~ Prone

Rate of acquisition for attaining prone locomotor movements varies more than any other voluntary movement


Locomotion ~ Prone

Locomotion evolves from children gaining the ability to position their bodies for movement from one location in space to another

7 months: elevates trunk slightly; forward arm extension and flexion creates occasional forward Movement;leg flexion occasionally creates backward crawling


Locomotion ~ Prone

Crawling (7-8 months) Precedes creeping Inefficient, highly variable

arm and leg movements intended to propel the body forward

Body is dragged Creeping (9-12 months)

Contralateral or homolateral pattern

More efficient form of prone locomotion

Body is elevated


Locomotion ~ Upright

Walking ~ the culmination of the acquisition of voluntary movement

There is little evidence demonstrating that early walking will accelerate or refine future skill performance



7 months: walks with considerable support or assistance

10 months: walks laterally around furniture using handhold for support

7 months



11 months: walks when led with slight handhold to maintain balance

12 months: walks unassisted



Experience is an important indicator in mature walking patterns

Children with smaller bones or linear frames walk somewhat earlier than larger-boned or larger-framed children

A child's muscle mass at 6 months of age may predict onset of independent walking



Training children on a treadmill Increases number of steps taken Aids children with non-stable walking patterns

Ground reaction forces may be used to help children with gait abnormalities and neurological disease


Manipulation ~ Reaching, Grasping, Releasing

Use of the hands enables children to gather information about their environment in a new way

Recall that early manipulation is reflexive Palmar grasp reflex



Phase I Phase II

Simultaneous reaching and grasping

Differentiated reaching and grasping

One-handed reaching Two-handed reaching

Visual initiation of the reach Visual initiation and guidance of the reach

Visual control of the grasp Tactile control of the grasp



Birth Phase I reaching

1 month Phase I reaching disappears

4 months Phase I reaching reappears

4-5 months Unable to receive multiple toys

5-6 months Thumb used to oppose fingers in grasping

6 months Receives two toys while storing one toy in opposite hand

6-8 months Receives two toys while storing one toy in opposite hand



9 months Adjusts arm and hand tension to object’s weight after grasping

9-10 months Thumb can oppose one finger in grasping

9-11 months Receives three toys; stores first two toys on lap or chair

12 months Adjusts arm and hand tension upon repeatedly receiving the same object

12-14 months Receives three or more toys and crosses midline to hand toys to other person

18 months Releases objects with relative ease; anticipates arm and hand tension for repeated presentation of same object; expects unknown long objects to weigh more than short objects



Development of prehension continues to evolve until the end of the first decade of life


Anticipation and Object Control in Reaching and Grasping

By 18 months, infants exhibit anticipation Given the same object, repeatedly, infants

display awareness that an object weighs the same

Anticipation is not always accurate Expects unknown long object to weigh more that

short object Anticipation and strength of grip develop over

several years (2yr to 9yr)


Anticipation and Object Control in Reaching and Grasping

9 months Adjust weight of object after grasping itLimited anticipatory abilities

1 year Develops skill in adjusting arm and hand tension when handed an objectNo carry-over to new objects

18 months Child exhibits anticipationAware that the same object weighs the sameDevelops a rule that similar objects weigh more or less than the familiar object (uses length)Not always accurate

2 years Greater speed with grasping an object coupled with less force

3 years Greater speed with grasping an object couplded with greater force

4 years Children control rate of speed in grasping

Burst of speed to grasp


Bimanual Control

Complementary use of two hands to achieve a goal (receiving toys) is evident at 6-8 months

4-5 months Varying abilities

Child cannot handle more than one toy

6-8 months Highly developed reaching and grasping

Easily grasps first toy and sometimes a second one

Cannot handle three toys

9-11 months Can hold on to three toys

May place one of the objects on the lap or table

12-17 months Hands toys to parent or other adult for safekeeping while more toys are grasped

Older children use a storage method to handle more toys


Bimanual Control

Walking is correlated with child’s ability to grasp with one hand

Using a one or two hand grasp may be related to walking experience Less walking experience: one hand Greater walking experience: two hands


© 2007 McGraw-Hill Higher Education. All rights reserved. Voluntary Movements of Infancy Chapter 10.

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