Postural Control Flashcards
_______ ______ = controlling of the body’s position in space.
postural control
What are the 3 goals of postural control?
- To support the body against gravity and other external factors
- To maintain the COM aligned and balanced over the BOS
- To stabilize parts of the body while moving other parts
_______ ___ ________ = the perimeter of the BOS beyond which we cannot maintain balance, how far the body’s COM can be moved over the BOS
Limits of stability
______ ____ _________ = a point of application of the GRF
centre of pressure
____ ____ _____ ______ = when the body contacts the ground, the ground “pushes” back on the body with a force equal in magnitude but opposite in direction
ground reaction force vector
______ ____ _____ = a point in space where there is equal amounts of body mass on all sides.
centre of mass
The location of the COM changes with __________.
movement
The ____ _____ _____ is the point at which the gravity appears to act.
centre of gravity
The _____ _____ ______ is the are defined by the points of contact between the body and the environment.
base of support
______ _____ = small movements of the body mass which occur when unsupported.
postural sway
The amount of sway is increased in the elderly and some __________ conditions.
pathological
What two things can you use to measure postural sway.
- COM
2. COP
How can the net centre of mass be calculated?
Mass of segment(s) multiplied by the co-ordinates of the COM, divided by the mass of the segment
Anticipatory postural control is enabled by _____________ control.
feedforward
In ________ _____, signals from sensors are compared with a desired state, represented by a reference signal.
feedback control
In feedback control, the difference or error signal is used to adjust the ______.
output
Feedback control is a _______ loop system.
closed
In ____________ ______ system, it predicts the disturbances and produces actions to maintain stability using prior experience to make a “best guess” action.,
feedforward control
Feedforward control is an _____ _____ system.
open loop
__________ ________ control = retuning sensory and motor systems in expectation of postural demands created by internal or anticipated external perturbation.
anticipatory postural
Anticipatory postural control is is based on what two things?
- previous experience
2. learning
What are 4 examples of anticipatory postural control?
- Arm raising while standing
- Opening/pulling on a door
- Rising on toe
- Stepping over an obstacle
________ ______ control = responses to an unanticipated eternal perturbation.
reactive postural
The stretch reflex is ________ and have a latency of ___ms.
monosynaptic; 30
The longer latency stretch reflex is _______ and has a latency of ____ms.
60+
What is the latency of voluntary movement ?
> 200ms
Postural responses are triggered by what 3 types of sensory inputs ?
- somatosensory
- vestibular
- visual
What is included in the somatosensory system?
- muscle proprioceptors
- muscle spindles
- GTO
- joint receptors
- cutaneous receptors
Somatosensory are most important during fast perturbations and respond within ___ - ___ ms.
60-100
When are responses due to vestibular input the most important ?
when eyes are closed and head is rotating
Muscles reflexes from visual cues are around ____ms.
200
__ in __ persons over the age of 65 and __ in __ persons over 80 experience a fall.
1/3; 1/2
In an elderly population, serious injuries occur in approximately ___ of these falls.
1/4
Give 5 examples of why someone may fall.
- balance issues
- muscle strength loss
- neurological impairments
- medications
- endurance issues
What are 3 clinical assessments of balance?
- berg balance scale
- functional reach test
- activities-specific balance confidence scale
What is the most common clinical assessment of balance ?
berg balance scale
A score less than ___ on the berg balance scale is considered at risk for falls.
46
In the functional reach test, you record the difference between the start and end position of the _________.
metacarpals
Scores less than ___ or ___ inches on the functional reach test indicate limited functional balance.
6-7
Most healthy individuals with adequate functional balance reach ___ inches or more on the functional reach test.
10
When leaning forward, the COM must move _____ slightly.
down
