Postural Control

What is postural orientation?

Ability to maintain useful relationships between body segments AND between the body and the environment to perform a task

What is postural stability?

• Ability to control COM in relationship to the BOS.

• Formal phase for balance

What is a key variable controlled by the postural control system?

COM

What is center of gravity (COG)?

Vertical projection of COM on the ground

What is center of pressure (COP)?

Center of distribution of total force applied to a supporting surface

What two components are involved with a task?

Orientation and stability

What is steady state balance control?

Keeping COM in BOS in reasonably predictable, unchanging conditions.

No dual tasking, can still be moving

What is reactive balance control (aka feedback control)?

Unexpected challenges to posture. Ex: tripping and recovering your balance.

What is anticipatory/proactive (aka feedforward control)?

Expected challenges to posture.

What is the alignment of the plum line in static stance (aka quiet stance)?

• Between mastoid

• A point just in front of shoulder joints

• Hip joints or just behind

• Point just in front of center of knee joints

• Point just in front of ankle joints

Are there small amounts of postural sway in quiet stance?

Yes

The ankle strategy is normally used to recover balance in response to what?

• A small, slow push

• A loss of balance (LOB) occurring in the anterior-posterior direction

What muscles are used to recover from forward sway in ankle strategy?

• Gastroc

• Hamstrings

• Paraspinals at end

What muscles are used to recover from backward sway in ankle strategy?

• Ankle DFs

• Quads

• Abdominals

Hip strategy is normally used to recover balance in response to what?

• Large, fast push

• Push coming from A-P OR M-L direction

What muscles are activated to recover from forward sway in the hip strategy?

Abdominals and quads

What muscles are activated to recover from backward sway in the hip strategy?

Paraspinals and hamstrings

When is suspensory strategy used to recover balance?

• Catching a heavy object or moving over an unstable surface.

• Classic example is walking over an unstable floor, like water on tile or ice.

How does suspensory strategy present?

Person will lower their COG with B LE flexion or a small squat

When is the stepping strategy used to recover balance?

• Individual to each person

• Usually when the limit of balance is reached and BOS has to change

• People may use it when no specific instructions are given on how to catch oneself.

What form of reactive control is stepping strategy known as?

Protective.

When is reach-to-grasp normally used to recover balance?

When the limit of balance is reached and BOS has to change

Compare the speed at which the act of taking a step or reaching to grasp to correct balance is to volitional stepping/reaching?

To correct balance is twice as fast

What form of reactive control is reach-to-grasp strategy known as?

protective

What is the primary joint for recovery of stability in ML direction?

Hip

Clinically, when you ask someone to do a SLS, what posture/balance controls are you looking at?

• Anticipatory postural control

• Proactive balance control

At what age does all three sensory systems contribute to balance?

7 years old

What is the cognition component of focus?

Attention; seen as a limited resource

Is posture a priority in intact young adults?

Ye