Postural control

Question 1

What are the 2 functional goals of postural control

Answer 1

Postural orientation
Postural equilibrium

Question 2

What is postural orientation

Answer 2

Active control of body alignment and tone of trunk and head with respect to gravity

Question 3

What is postural equilibrium

Answer 3

Co-ordination of sensory motor strategies to stabilize body’s center of mass during self initiated and externally triggered disturbances of postural stability

Question 4

What are the components of stability

Answer 4

Biomechanical contraints
Movement strategies (motor systems)
Orientation is space
Cognitive processing
Musculoskeletal components

Question 5

What is postural control

Answer 5

Reflexes triggers equilibrium responses based on visual, vestibular and somatosensory triggers.
Posture is a complex skill from interaction of multiple sensory-motor and perceptual-cognitive processes
Used to determine whether postural pathologies are due to underlying impairments or compensatory strategies

Question 6

What factors influence postural control

Answer 6

Joint stability
ROM
Endurance
Coordination
Fatigue
Reaction Time
Emotion arousal
Environment
Cogitive
Visual/ Vestibular and SS systems
Age

Question 7

What is feedback

Answer 7

Receiving info via vestibular, visual or somatosensory systems
Processing & integrating information leading to re-establish balance by compensatory reactions
*Compensatory = reactive

Question 8

What is feedforward

Answer 8

Disturbances like depolarizing movements are cognitively anticipated
To sustain PC with self initiated counter movements - pre activation
*anticipatory = proactive

Question 9

What are the different types of postural control & explain each

Answer 9

Steady state (static) : safe and stable independent standing or sitting
Dynamic: ability to hold posture while moving between points
Proactive: maintain stability while performing tasks that are potentially destabilizing - prepare for pertubation
Reactive: recovering to a stable position following unexpected disturbances
Adaptive: modify motor response because a change in environment/task/demand

Question 10

What are the different motor systems involved in PC

Answer 10

Movement/balance strategies: limits of stability/ returning body to equilibrium
Change of BoS: stepping or reaching strategy
Keep base of support fixed: ankle/hip strategy
Additional - suspensory

Question 11

What is the ankle strategy

Answer 11

Involuntary movement detected through proprioceptive system
Muscle control is from distal to proximal
Flexible inverted pendulum on 1 axis
UB & LB moves in same direction
Occurs with minimal perturbance in balance
Occurs in younger individuals with low risk of falling

Question 12

What factors limit ankle strategy

Answer 12

inadequate ROM & strength
not a firm/broad surface
loss of sensation in feet/ankle - ex neuropathy

Question 13

What is the hip strategy

Answer 13

Involuntary movement detected through vestibular system
Control is proximal to distal
Inverted pendulum with 2 axis
UB moves in opposite direction as LB
Controls both anterior-posterior and medial-lateral sway
Medial-lateral involves weight shift from foot to foot
Elderly - fear of falling
Inadequate ankle torque
Narrow/compliant surfaces

Question 14

Factors limiting hip strategy

Answer 14

Inadequate ROM in hip extensors & flexors
Poor strength in hip complex
Vestibular deficits

Question 15

What is the stepping/reaching strategy

Answer 15

Involuntary movement detected through the vestibular system
Used when there is greater perturbance
Taking a step = new BoS to recover equilibrium
Pertubations displace CoG & BoS and maximum limits of stability and sway is too fast for hips

Question 16

Factors limiting the stepping/reach strategy

Answer 16

inadequate LB strength/power/ ROM
Slow central processing speed
Not rapid enough limb movement initiation

Question 17

What is the suspensory strategy

Answer 17

Used during standing/ambulation
Bend trunk forward with knee/hip flexion
May progress to squat position to lower CoG

Question 18

What sensory systems are involved in PC

Answer 18

Visual - gives us reference to the environment
Vestibular - gives us an internal reference
Somatosensory- proprioception and tactile to determine our position in space and how you are moving in relation to your environment

Question 19

What are the different sensory strategies

Answer 19

Sensory reweighing
Sensory integration

Question 20

What is sensory reweighing

Answer 20

changing of your sensory environment will cause a relative dependence on each of these sense
Firm BoS:
70% SS
10% Visual
20% Vestibular

Unstable surface
10% SS
30% Vision
60% Vestibular

Question 21

What are problems with sensory reweighing

Answer 21

Peripheral vestibular loss
SS loss from neuropathy (SNS)
Alzheimers (CNS)
Stroke
Acquired via training (dancers)

Question 22

What are the 4 steps to program determination

Answer 22

1. determine functional performance & health goals
2. identify postural control systems/considerations
3. Design a test battery
4. Implement an intervention

Question 23

What to include in a training program

Answer 23

Specificity
Progressive overload
Practice design
Feedback
Mastery

Question 24

What are the modes of balance control

Answer 24

CoG control
Treatment of impairment causing balance disruption
Treatment of balance strategies
Treatment of sensory impairments
Substitution strategies
Dynamic/Gait training