8.5 Proactive Balance Controls

Question 1

What is proactive (anticipatory) balance control?

Answer 1

The ability to activate postural muscles in advance of a predicted disturbance to maintain stability.

Question 2

How is proactive balance adapted?

Answer 2

It is adapted to different tasks and environmental demands.

Question 3

What system is primarily responsible for anticipatory control?

Answer 3

The central nervous system (CNS).

Question 4

What does the CNS do in anticipatory balance control?

Answer 4

It uses prior experience to form an internal representation of movement demands and pre-tunes the motor system.

Question 5

What does the “light box” example demonstrate?

Answer 5

The CNS anticipates the required muscle force based on prior experience, leading to overshooting when expectations are wrong.

Question 6

What does the preparatory phase of proactive balance involve?

Answer 6

Activation of postural muscles before the prime mover muscles to maintain stability.

Question 7

What does the compensatory phase of proactive balance involve?

Answer 7

Activation of postural muscles after the prime movers to stabilize the body using feedback.

Question 8

In an example of leg lifting, which muscles activate first?

Answer 8

Muscles on the opposite (contralateral) side activate first to maintain stability.

Question 9

What does the leg-lifting experiment show about anticipatory control?

Answer 9

The body anticipates the need for stability before initiating movement.

Question 10

How does sitting affect anticipatory postural muscle activity?

Answer 10

Anticipatory activity decreases as external support increases.

Question 11

How does task difficulty affect anticipatory postural activity?

Answer 11

It increases with greater task load or challenge.

Question 12

When does anticipatory postural control increase?

Answer 12

When a task is less supported or more challenging.

Question 13

When does anticipatory postural control decrease?

Answer 13

When there is more external support or stability.

Question 14

What are the two phases of proactive balance control?

Answer 14

The preparatory phase (feedforward) and the compensatory phase (feedback).

Question 15

What type of control does the preparatory phase rely on?

Answer 15

Feedforward control.

Question 16

What type of control does the compensatory phase rely on?

Answer 16

Feedback control.

Question 17

Why are mistakes in movement (like over-lifting a light box) important?

Answer 17

They show that the CNS relies on predictive, anticipatory mechanisms based on past experience.

Question 18

How can proactive balance be trained clinically?

Answer 18

Through repeated exposure to task variations that promote anticipatory muscle activation and adaptive motor planning.