NM chapter 8: development of postural control

what is the limiting factor in babies movement?

postural control

predictable sequence of motor behaviors

head control → sitting → crawling → walking

age that most babies are able to sit without support

6 months

age that most babies are able to stand independently

11 months

age that most babies are able to walk independently

12 months

how is reflex theory applied to postural development?

emergence of posture and movement control dependent on the appearance and subsequent integration of reflexes 

some of the infant reflexes include…

…rooting, bambinski, grasping, sucking

how is systems theory applied to postural control?

postural control is the complex interaction between neural and musculoskeletal systems. 5 major components: changes in musculoskeletal system, development of coordination, development of individual senses, development of sensory organizing strategies, and development of cognitive resources and strategies

describe general movement of infants

complex-involving the whole body, occur often, vary in intensity and velocity

what sensory information helps with emerging head control? 

vision (important in calibration of vestibular and proprioception system), vestibular, somatosensory (contributes to head control)

emergence of independent sitting happens when… 

…infants are able to control spontaneous sway sufficiently to remain upright

progression of independent sitting

no control → attempts to initiate upright sitting → partial control with large range of body sway → functional control with minimal sway

what does emergence of independent sitting look like?

reactive balance control in the trunk available to a limited extent in infants before sitting develops, trunk control improves and is associated with improved reach trajectories. rely heavily on vision

to stand independently infants must learn to…

balance within reduced stability limits, control additional degrees of freedom, and recalibrate sensorimotor representations for postural control

what is significant about hips in infants walking?

infants don’t have the adaptive ability to use the hips in balance, hip-dominated responses become present in 3 to 6 months of walking

why is balance more difficult for children?

shorter and closer to the ground, top heavy, body moves faster when unbalanced

compensatory postural responses of children ___ of age are more variable and slower than those of adults

less than 15 months

how long does it take for children postural responses to become like adults?

7 to 10 years

describe the progression from crawling to walking

attractor wells. lack of changes in movement can be seen due to just a very small piece of puzzle being left out, children will use a movement until it is no longer most efficient, then will switch and be instable and variable in the new movement

what happens if the attentional capacity of the child is exceeded?

the postural task or the cognitive task or both will deteriorate. the postural demands of a child tax their attentional resources

how do cognitive systems develop within postural control?

changes in motor components-body morphology and synergies, shift from predominance of visual control of balance to somatosensory control, increasing automaticity of postural control