Lecture 5: Balance and Postural Control

Question 1

WWhat is postural control?

Answer 1

the act of maintaining achieving or restoring a state of balance during any posture activity

Question 2

What is balance?

Answer 2

balance= equilibrium

even distribution of weight enabling someone to remain upright and steady

Question 3

What is BOS?

Answer 3

boundary created by body part in contact with supporting surface

Question 4

What is COM?

Answer 4

mean location of total mass in the body

Question 5

What is COM in standing?

Answer 5

2/3 of body height above BOS

Question 6

What is COG?

Answer 6

mean location of moments and forces acting on a body should equal zero

Question 7

What is LOS?

Answer 7

furthest distance in any direction a person can lean without loss of balance or altering the original BOS

Question 8

What is LOS influenced by?

Answer 8

person’s height and foot length

Question 9

What is postural control dependent on?

Answer 9

the environment, ability to maintain in any given sensory environment

Question 10

What does adaptive postural control require?

Answer 10

requires sensory and motor modifications as task and environment changes, constantly changing

Question 11

What is reactive balance?

Answer 11

unexpected external force, displacement of COM, alters BOS

sensory input drives corrective response (feedback)

Question 12

What is proactive balance?

Answer 12

anticipation of a destabilizing force

feed forward mechanism drive response based on past experiences

Question 13

What are goals of balance?

Answer 13

1. postural stability (dynamic and static)
2. postural orientation
3. functional activities and interaction with environment

Question 14

What is sensorimotor integration?

Answer 14

complex interactions of ms and neural systems required

Question 15

What are 3 components of sensorimotor system?

Answer 15

1. sensory- vision, vestib, somato
2. integration of info from CNS
3. motor response

Question 16

What does sensory systems tell us about our body?

Answer 16

tell us where COG is relative to our BOS and environment

must be timely and accurate

Question 17

Which factor is most important to balance of all senses?

Answer 17

somatosensation

Question 18

Why is it so important?

Answer 18

gives us information about relationship of body to supporting surfaces from receptors like: joint and muscle proprioceptors and cutaneous receptors

think of video of guy who lost proprioception

Question 19

How does vision help with balance?

Answer 19

perception of our body compared to environment, recognition of environmental factors

Question 20

How does vestibular system affect balance?

Answer 20

otoliths- linear acceleration of head

semicircular canals- angular and rotation of head

Question 21

What is order of CNS sensory weight?

Answer 21

somato, vision, vestibular

Question 22

What is ankle strategy?

Answer 22

small shifts of COM, body rotates on ankle jt, muscles activated distal to proximal

Question 23

What is hip strategy?

Answer 23

much larger faster amplitudes of COM displacement

effective on smaller surfaces

muscles activated proximal to distal

Question 24

What is stepping strategy?

Answer 24

used when COG is displaced beyond BOS

take a step to prevent fall