posture and balance Flashcards

1
Q

what is balance

A

quiet standing - involving keeping the centre of mass within the base of support

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2
Q

what allows the body to stand in the inverted pendulum model of human standing

A

using torque provided by active calf muscles

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3
Q

what is the equation for inverted pendulum stance

A

F= MG
force= mass x gravitational constant

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4
Q

center of gravity or mass is what

A

a point the mean position of the matter in a body or system

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5
Q

what is the centre of pressure

A

a point on a surface through the resultant force applies total pressure force

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6
Q

Centre of pressure oscillates forward and back to maintain…

A

centre of mass - sway can be quantified by com

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7
Q

standing is a what control process

A

sensorimotor

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8
Q

what are the 3 things for why we sway

A

sensory estimation
motor output
external and internal perturbations - b

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9
Q

what 5 things keep us upright

A

vision
proprioception
vestibular apparatus
touch
efference copy of motor command and prediction

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10
Q

2 different frequency control .. are…

A

slow / low frequency - visual control
fast/ high frequency for vestibular input

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11
Q

removing visual information cause’s the body to..

A

sway

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12
Q

quality of visual input can also effect

A

sway

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13
Q

distant visual information is useless for balance - t or f and why

A

t - no retinal motion

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14
Q

what is motion parallax

A

objects appear to move relative to each other
depending on focus point

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15
Q

objects appear to move relative to each other when we sway bc it

A

provides more information

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16
Q

the largest reduction is observed when foreground and background scenery are .

A

present together and furthest apart

17
Q

what is perturbing visual input- visual vection

A

a false sense of motion induced by a false scene

18
Q

what is this an example of
watching an adjacent train depart the station

A

visual vection

19
Q

visual vection may impact what

A

sway and standing control / posture

20
Q

subjects sway in the direction of

A

visual scene movement

21
Q

the brain interprets forward scene motion as … and creates …..

A

backward body motion ….a compensatory forward response

22
Q

effect of predictability on visual response

experimental triggers motion unexpectantly what response

A

big sway

23
Q

ankle creates torque around calf to help prevent the body doing what

A

toppling forward

24
Q

changes in muscle stiffness represent changes in what

A

muscle reflexes

25
Q

removal of sensory information effects what

A

posture

26
Q

muscle stiffness and balance is reduced with less

A

sensory information (visual and no vestibular)

27
Q

ankle torque increases as the angle of ankle …

A

increases

28
Q

the stiffness in the ankle is too low to permit

A

passive standing - standing without active modulation of emg

29
Q

balance involves keeping com within

A

base of support

30
Q

sway occurs mostly at which joint

A

ankle

31
Q

sway arises from

A

lack of sensory information