Postural Control

Question 1

postural control

Answer 1

control of body position in space

Question 2

3 goals of postural control

Answer 2

support body against gravity / external forces
maintain COM over BOS
stabilize some parts of body while others move

Question 3

limits of stability

Answer 3

perimeter of BOS beyond where we can control

ie. how far COM can be moved over BOS

Question 4

Centre of pressures

Answer 4

point of ground reaction force vector

Question 5

Ground reaction force vector

Answer 5

when body contacts ground, ground pushes back on body with equal and opposite magnitude

Question 6

Centre of Mass

Answer 6

point where equal body mass on all sides

Question 7

does COM need to be on body

Answer 7

no

Question 8

Centre of gravity

Answer 8

point where gravity appears to act

Question 9

base of support

Answer 9

points of contact between body and enviornment

Question 10

base of support if sitting?

Answer 10

ie. under feet under buttocks etc..

Question 11

postural sway

Answer 11

small movements of body when unsupported (sitting or standing)

Question 12

postural sway is NOT normal T/F

Answer 12

false - its normal

Question 13

What is used to measure postural sway

Answer 13

COM, COP (center of pressure)

Question 14

Anticipatory postural control enabled by?

Answer 14

feedforward control

Question 15

feedback control

Answer 15

sensory signals compared with desired state

error = body adjusts

Question 16

feedback control open or close loop system

Answer 16

closed

Question 17

feedback forward

Answer 17

predicts disturbances and produces actions to maintain stability
makes “best guess” action

Question 18

feedback forward open or closed loop system

Answer 18

open

Question 19

anticipatory postural control

Answer 19

sensory/motor system expectation of postural demands created by internal or anticipated external perturbation

based on learning / exp

Question 20

examples anticipatory postural control

Answer 20

arms raise while standing, open/pull door, rising on toe etc..

Question 21

reactive postural control

Answer 21

response to unanticipated external perturbation

Question 22

Postural response triggered by 3 types of sensory inputs

Answer 22

somatosensory system
vestibular receptors
visual input

Question 23

function mm spindles

Answer 23

sense length

Question 24

role golgi tendon

Answer 24

sense force/ strength

Question 25

parts of somatosensory system

Answer 25

mm proprioceptors, mm spindles, golgi tendons, joint receptors, cutaneous receptors

Question 26

what do vestibular receptors do

Answer 26

sense sway through head motion

Question 27

how long does it take somatosensory system to react

Answer 27

60-100 ms

Question 28

if eyes closed head turned which receptors will be most important

Answer 28

vestibular - but its usually somatosensory otherwise

Question 29

how long does it take mm reflexes from visual cues to respond

Answer 29

200 ms

Question 30

name three clinical assessments of balance

Answer 30

berg balance, functional reach, activity specific balance confidence scale (ABC)

Question 31

What score on berg test makes you a risk for falls

Answer 31

less than 46

Question 32

berg scale is good for who bad for who

Answer 32

Good for GF strong patient etc.. bad for sport med patient

Question 33

what score on function reach test is bad

Answer 33

less than 6 or 7 inches means limited functional balance

healthy ppl can hit 10 inches