Posture-balance

Question 1

Both posture and balance require _____ _____ effort to counterbalance the external forces acting upon the body

Answer 1

active neuromuscular

Question 2

_____ is the predominant force acting upon the body, which also interacts with any loads we attach to the body

Answer 2

gravity

Question 3

posture is established and maintained through the activation of the “antigravity muscles” that act upon the _____skeleton

Answer 3

axial

Question 4

activation of “antigravity muscles” generates muscle _____, which provides “resistance” by the muscle to _____ caused by external loads

Answer 4

tone; stretch (locking muscle length)

Question 5

muscle tone is often viewed as the overall _____ of the muscle arising from active force generation

Answer 5

stiffness

Question 6

postural muscle tone is established through a sustained, but _____ level of activation to maintain a “counterforce” level of tension in opposition to the external loads

Answer 6

variable

Question 7

_____ is established and maintained by aligning the body’s center of mass over its base of support, and by stabilizing and supporting the body whenever its center of mass moves _____ from its base of support

Answer 7

Balance; away

Question 8

A point that represents the average position of the body’s total mass … the net effect of gravity upon the body is through its center of mass. What is this known as?

Answer 8

Center of mass

Question 9

What is base of support?

Answer 9

the ground, or platform upon which we make contact (e.g.with our feet), to which the gravitational force, acting through the body’s center of mass, is applied

Question 10

Is posture and balance interrelated?

Answer 10

Yes

Question 11

posture establishes the “geometry” between the body’s _____ and its
current _____.

Answer 11

center of mass; “stance”

Question 12

whenever the center of mass is “displaced”, “_____ _____ vectors” must become activated to prevent a loss of balance

Answer 12

“counteracting force vectors”

Question 13

“force vectors”: _____ forces, established through muscle _____, to counteract external forces that would otherwise push the body off balance

Answer 13

pulling; activation

Question 14

when muscle activation is insufficient to counteract the loss of balance, we must then _____ relative to the center of gravity to re-establish balance

Answer 14

alter our stance

Question 15

Change of posture may put the body _____.

Answer 15

Unbalanced

Question 16

Maintaining balance requires _____ _____.

Answer 16

“postural equilibrium”

Question 17

_____ _____ is achieved when the “counter-force” muscles are appropriately activated to provide the force needed to offset the displacement forces that would otherwise throw the body off balance

Answer 17

postural equilibrium

Question 18

The specific pattern of muscle activation will be _____ dependent, and may often also involve ______ learning

Answer 18

context; experience-based

Question 19

Muscles activated to maintain postural equilibrium provide _____ against the forces that would otherwise cause a loss of balance

Answer 19

compensation

Question 20

Forward and backward _____ are shifting the center of mass relative to the base of support.

Answer 20

sway

Question 21

What are the 2 forms of compensation of loss of balance?

Answer 21

1. Counteract the initial displacement

2. Stabilize and brace the body through active counteracting force vectors

Question 22

What is the sequential order for compensatory activation of muscles if there is disturbance to postural equilibrium?

Answer 22

1. Those closest to the origin of displacement are activated first, to COUNTER ACT.
2. compensatory muscle activation continues progressively moving away from the origin of displacement, to STABILIZE and BRACE.

Question 23

Compensatory motor responses to counteract a disturbance in posture are activated reflexively. What are the sensory inputs?

Answer 23

Proprioceptive and vestibular, along with visual.

Question 24

(T/F) Postural adjustments often improve upon repeated trial.

Answer 24

True

Question 25

During forward sway, is gastrocnemius muscle contracted or inhibited?

Answer 25

Contracted

Question 26

During tilt (hilly) of the ground surface, is gastrocnemius muscle contracted or inhibited?

Answer 26

Inhibited

Question 27

Postural adjustment can be _____ through experience that may be executed in advance of a stimulus.

Answer 27

learned

Question 28

_____ awareness contributes towards deciding upon which postural set “program” to activate

Answer 28

Perceptual

Question 29

Without support, gastrocnemius muscle and hamstring muscles are (activated/inactivated) in advance of biceps to prevent forward sway induced by pulling agains the handle.

Answer 29

Activated

Question 30

With the body supported, gastrocnemius muscle and hamstring muscles are (activated/inactivated) in advance of biceps to prevent forward sway induced by pulling agains the handle.

Answer 30

Inactivated

Question 31

Before initiating voluntary movements when the body is unsupported, a compensatory postural adjustment will normally be _____ in advance of activation of the movement itself

Answer 31

initiated/activated

Question 32

“central command” refers to the motor signals that will execute the intended movement – (2 types of signaling)

Answer 32

Feedforward and feedback signaling

Question 33

What is feedforward?

Answer 33

Anticipatory motor commands (Postural adjustment)

Question 34

What is feedback signaling?

Answer 34

Acting through motor reflexes (Fine adjustments)

Question 35

Awareness of current body position, and of intended movement generates
adjustments in muscle tone in advance of the initiation of voluntary movement. (Feedforward or Feedback signaling?)

Answer 35

Feedforward

Question 36

Such responses are automatic and rapid, and scale in magnitude relative to forces and motions to achieve and maintain stable posture. (Feedforward or feedback signaling?)

Answer 36

Feedback

Question 37

Can feedback response be improved through learning and practice?

Answer 37

Yes!

Question 38

Feedforward/feedback is anticipatory

Answer 38

Feedforward

Question 39

Feedforward/feedback is compensatory

Answer 39

Feedback

Question 40

Posture and balance are monitored and maintained by three primary sensory systems:

Answer 40

Proprioceptive, vestibular, and visual

Question 41

Proprioceptors report changes in orientation and balance via changes in the_____ and _____ of specific muscles.

Answer 41

length and tension

Question 42

Which sensory system has the SHORTEST latency?

Answer 42

Proprioceptive (fastest to respond)

Question 43

Which sensory system reports head motion?

Answer 43

Vestibular receptors

Question 44

Which sensory system reports motion relative to external objects in the visual field?

Answer 44

Visual input

Question 45

Vestibular and visual responses are almost _____ as slow as proprioceptive responses.

Answer 45

twice

Question 46

Afferent input from just one sensory system may lead to _____ by the brain that could lead to an inappropriate postural adjustment.

Answer 46

“misinterpretations”

Question 47

Effective postural adjustments therefore require the integration of more than one sensory input, so as to generate the appropriate _____ _____.

Answer 47

sensorimotor transformations

Question 48

Which sensory system provide feedback into spinal cord motor neurons and motor circuits to provide rapid “antigravity stabilization”?

Answer 48

Proprioceptive feedback

Question 49

What is “antigravity stabilization”?

Answer 49

Counterforce applied against gravitational weight

Question 50

(T/F) Maintaining balance when challenged by continuously varying (or dynamic) loads upon the body and/or during active movements requires the integration of additional sensory inputs (vestibular and visual).

Answer 50

True

Question 51

Integration of visual and vestibular sensory inputs is largely _____involving nuclei within the brainstem and cerebellum.

Answer 51

sub-cortical