Chapters 7 & 9

Question 1

Relationship of body segments to one another, as well as to the position of the body with reference to gravity and the base of support

Answer 1

Alignment

Question 2

Center of Mass

Answer 2

point at center of the total body mass

Question 3

Center of Gravity

Answer 3

vertical projection of the center of mass

Question 4

Center of Pressure

Answer 4

center of distribution of total force applied to supporting surface

Question 5

Posture

Answer 5

the biomechanical alignment of the body and the orientation of the body in the environment

Question 6

Postural control

Answer 6

control of the body’s position in space for orientation and stability

Question 7

Postural tone

Answer 7

activity increases in antigravity muscle, which keeps the body from collapsing in response to the pull of gravity during quiet stance

Question 8

Postural orientation

Answer 8

ability to maintain an appropriate relationship between body segments, and between the body and the environment for a specific task

Question 9

Postural stability or balance

Answer 9

ability to control the center of mass in relationship to the base of support

Question 10

Clinical definition of fall

Answer 10

an event that results in a person coming to rest inadvertently on the ground (unplanned or unexpected contact with a supporting surface)

Question 11

Research definition of fall

Answer 11

movement of the CoM outside of the base of support (including stepping to recover stability)

Question 12

How is the body controlled during quiet stance?

Answer 12

The CoP works to control the CoM moving the body backward and forward.

Question 13

Feedback Control

Answer 13

postural control that occurs in response to sensory feedback (somatosensory, visual or vestibular) from an unexpected perturbation

Question 14

Feedforward Control:

Answer 14

postural responses that are made in anticipation of a voluntary movement potentially destabilizing in order to maintain stability during movement

Question 15

Synergy:

Answer 15

the functional coupling of groups of muscles that are constrained to ACT TEGETHER as a unit

Question 16

Ankle Strategy, Forward sway:

Answer 16

to prevent falling on face, use posterior muscles to restore CoM

Question 17

Ankle Strategy, Backward Sway:

Answer 17

to prevent falling on back, use anterior muscles to restore CoM

Question 18

What is the timing of activation in the ankle strategy?

Answer 18

from distal to proximal muscles

Question 19

What is the ankle strategy used for?

Answer 19

smaller perturbations

Question 20

Hip strategy, forward sway:

Answer 20

to prevent falling on face, use large anterior muscles

Question 21

Hip strategy, backward sway:

Answer 21

to prevent falling on back, use large posterior muscles

Question 22

What is the timing activation in hip strategy?

Answer 22

from proximal to distal muscles

Question 23

What is the hip strategy used for?

Answer 23

Useful for fast and large disturbance

Question 24

Stepping strategy:

Answer 24

When the ankle and hip strategies are not enough to maintain the balance, a step will restore the CoM.

Question 25

Lateral stability:

Answer 25

Mainly, muscles at the hip and trunk are used.

Muscle patterns are organized in a proximal-to-distal direction.

Question 26

What is the cerebellum in control of?

Answer 26

adaptation – the ability to modify postural muscle amplitude in response to changing tasks and environmental conditions

Question 27

What is the basal ganglia in control of?

Answer 27

postural set – the ability to quickly change muscle patterns in response to changing tasks and environmental conditions

Question 28

Factors contributing to aging:

Answer 28

primary or genetic

secondary or experiential

Question 29

Primary or genetic factors

Answer 29

contribute to the loss of neuronal function within a system over which we have LITTLE control

Question 30

Secondary or experiential factors

Answer 30

such as environment, nutrition, and lifestyle, affect our nervous system function over which we have MORE control

Question 31

When perturbation size and velocity increase, stable order adults:

Answer 31

showed increased amplitude of response as compared to young adults

Question 32

When perturbation size and velocity increase, unstable order adults

Answer 32

exhibited much more increased amplitude of response

Question 33

What is balance performance correlated with:

Answer 33

sensory/motor system function,
muscle weakness,
impaired synergy of muscle coordination and response to instability,
and limitation to adapt movement in reaction to changing tasks

Question 34

Compensatory step take in stepping reaction:

Answer 34

forward or backward stepping with one or more lateral

Question 35

Compensatory step take in reaching reaction:

Answer 35

initiation of arm movement, reach-to-grasp movement

Question 36

Sensory Weighting Hypothesis

Answer 36

When one sensory system is less reliable, the input to the CNS from that system is weighted less heavily, and inputs from other systems will be weighted more heavily

Question 37

With age, vibratory sensation threshold:

Answer 37

increases

Question 38

With age, tactile sensitivity

Answer 38

decreases

Question 39

With age, visual threshold

Answer 39

increases

Question 40

With age, visual acuity

Answer 40

decreases