Voluntary Movements of Infancy

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

2. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

3. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

4. “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” © 2007 McGraw-Hill Higher Education. All rights reserved.

5. The rate of acquisition for all voluntary movements during infancy may vary © 2007 McGraw-Hill Higher Education. All rights reserved.

6. Categorizing the Movements • Voluntary movement groups • Stability • Head control, upright posture • Locomotion • Creeping, crawling, walking • Manipulation • Reaching, grasping, releasing © 2007 McGraw-Hill Higher Education. All rights reserved.

7. Categorizing the Movements • Cephalocaudal pattern of development • Head control • Upper body control • Lower body control © 2007 McGraw-Hill Higher Education. All rights reserved.

8. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

9. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

10. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

11. Voluntary Control of 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

12. Voluntary Control of the Body 6 months: rolls from supine to prone position; maintains standing position when assisted 7 months: achieves sitting position from prone to supine position © 2007 McGraw-Hill Higher Education. All rights reserved.

13. Voluntary Control of the Body 8 months: sits alone; rolls from prone to supine position 9-10 months: pulls self to standing position, briefly maintains stand while holding external supporting object 12 months: stand unassisted © 2007 McGraw-Hill Higher Education. All rights reserved.

14. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

15. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

16. Locomotion ~ Prone • Rate of acquisition for attaining prone locomotor movements varies more than any other voluntary movement © 2007 McGraw-Hill Higher Education. All rights reserved.

17. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

18. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

19. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

20. Locomotion ~ Upright 7 months • 7 months: walks with considerable support or assistance • 10 months: walks laterally around furniture using handhold for support © 2007 McGraw-Hill Higher Education. All rights reserved.

21. Locomotion ~ Upright • 11 months: walks when led with slight handhold to maintain balance • 12 months: walks unassisted © 2007 McGraw-Hill Higher Education. All rights reserved.

22. Locomotion ~ Upright • 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

23. Locomotion ~ Upright • 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

24. 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 © 2007 McGraw-Hill Higher Education. All rights reserved.

25. Manipulation ~ Reaching, Grasping, Releasing © 2007 McGraw-Hill Higher Education. All rights reserved.

26. Manipulation ~ Reaching, Grasping, Releasing © 2007 McGraw-Hill Higher Education. All rights reserved.

27. Manipulation ~ Reaching, Grasping, Releasing © 2007 McGraw-Hill Higher Education. All rights reserved.

28. Manipulation ~ Reaching, Grasping, Releasing • Development of prehension continues to evolve until the end of the first decade of life © 2007 McGraw-Hill Higher Education. All rights reserved.

29. 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) © 2007 McGraw-Hill Higher Education. All rights reserved.

30. Anticipation and Object Control in Reaching and Grasping © 2007 McGraw-Hill Higher Education. All rights reserved.

31. Bimanual Control • Complementary use of two hands to achieve a goal (receiving toys) is evident at 6-8 months © 2007 McGraw-Hill Higher Education. All rights reserved.

32. 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.

33. The End © 2007 McGraw-Hill Higher Education. All rights reserved.