Postural Control

Question 1

_______ ______ = controlling of the body’s position in space.

Answer 1

postural control

Question 2

What are the 3 goals of postural control?

Answer 2

1. To support the body against gravity and other external factors
2. To maintain the COM aligned and balanced over the BOS
3. To stabilize parts of the body while moving other parts

Question 3

_______ ___ ________ = the perimeter of the BOS beyond which we cannot maintain balance, how far the body’s COM can be moved over the BOS

Answer 3

Limits of stability

Question 4

______ ____ _________ = a point of application of the GRF

Answer 4

centre of pressure

Question 5

____ ____ _____ ______ = when the body contacts the ground, the ground “pushes” back on the body with a force equal in magnitude but opposite in direction

Answer 5

ground reaction force vector

Question 6

______ ____ _____ = a point in space where there is equal amounts of body mass on all sides.

Answer 6

centre of mass

Question 7

The location of the COM changes with __________.

Answer 7

movement

Question 8

The ____ _____ _____ is the point at which the gravity appears to act.

Answer 8

centre of gravity

Question 9

The _____ _____ ______ is the are defined by the points of contact between the body and the environment.

Answer 9

base of support

Question 10

______ _____ = small movements of the body mass which occur when unsupported.

Answer 10

postural sway

Question 11

The amount of sway is increased in the elderly and some __________ conditions.

Answer 11

pathological

Question 12

What two things can you use to measure postural sway.

Answer 12

1. COM

2. COP

Question 13

How can the net centre of mass be calculated?

Answer 13

Mass of segment(s) multiplied by the co-ordinates of the COM, divided by the mass of the segment

Question 14

Anticipatory postural control is enabled by _____________ control.

Answer 14

feedforward

Question 15

In ________ _____, signals from sensors are compared with a desired state, represented by a reference signal.

Answer 15

feedback control

Question 16

In feedback control, the difference or error signal is used to adjust the ______.

Answer 16

output

Question 17

Feedback control is a _______ loop system.

Answer 17

closed

Question 18

In ____________ ______ system, it predicts the disturbances and produces actions to maintain stability using prior experience to make a “best guess” action.,

Answer 18

feedforward control

Question 19

Feedforward control is an _____ _____ system.

Answer 19

open loop

Question 20

__________ ________ control = retuning sensory and motor systems in expectation of postural demands created by internal or anticipated external perturbation.

Answer 20

anticipatory postural

Question 21

Anticipatory postural control is is based on what two things?

Answer 21

1. previous experience

2. learning

Question 22

What are 4 examples of anticipatory postural control?

Answer 22

1. Arm raising while standing
2. Opening/pulling on a door
3. Rising on toe
4. Stepping over an obstacle

Question 23

________ ______ control = responses to an unanticipated eternal perturbation.

Answer 23

reactive postural

Question 24

The stretch reflex is ________ and have a latency of ___ms.

Answer 24

monosynaptic; 30

Question 25

The longer latency stretch reflex is _______ and has a latency of ____ms.

Answer 25

60+

Question 26

What is the latency of voluntary movement ?

Answer 26

> 200ms

Question 27

Postural responses are triggered by what 3 types of sensory inputs ?

Answer 27

1. somatosensory
2. vestibular
3. visual

Question 28

What is included in the somatosensory system?

Answer 28

1. muscle proprioceptors
2. muscle spindles
3. GTO
4. joint receptors
5. cutaneous receptors

Question 29

Somatosensory are most important during fast perturbations and respond within ___ - ___ ms.

Answer 29

60-100

Question 30

When are responses due to vestibular input the most important ?

Answer 30

when eyes are closed and head is rotating

Question 31

Muscles reflexes from visual cues are around ____ms.

Answer 31

200

Question 32

__ in __ persons over the age of 65 and __ in __ persons over 80 experience a fall.

Answer 32

1/3; 1/2

Question 33

In an elderly population, serious injuries occur in approximately ___ of these falls.

Answer 33

1/4

Question 34

Give 5 examples of why someone may fall.

Answer 34

1. balance issues
2. muscle strength loss
3. neurological impairments
4. medications
5. endurance issues

Question 35

What are 3 clinical assessments of balance?

Answer 35

1. berg balance scale
2. functional reach test
3. activities-specific balance confidence scale

Question 36

What is the most common clinical assessment of balance ?

Answer 36

berg balance scale

Question 37

A score less than ___ on the berg balance scale is considered at risk for falls.

Answer 37

46

Question 38

In the functional reach test, you record the difference between the start and end position of the _________.

Answer 38

metacarpals

Question 39

Scores less than ___ or ___ inches on the functional reach test indicate limited functional balance.

Answer 39

6-7

Question 40

Most healthy individuals with adequate functional balance reach ___ inches or more on the functional reach test.

Answer 40

10

Question 41

When leaning forward, the COM must move _____ slightly.

Answer 41

down