Reflex and Posture

Question 1

Define “balance”

Answer 1

Dynamics of body posture to prevent falling

Question 2

Give examples of three strategies which help maintain posture

Answer 2

• Ankle strategy
• Hip strategy
• Stepping strategy

Question 3

During normal quiet standing, which strategy is used to maintain balance?

Answer 3

Ankle strategy

Question 4

In order to maintain balance, what must lie within the base of support?

Answer 4

A person’s centre of gravity

Question 5

Explain the reflex model of maintaining posture

Answer 5

The reflex model outlines that postural responses to perturbations arise by reflex pathways from sensory information

Question 6

Explain the systems model of maintaining posture

Answer 6

The systems model describes that posture is maintained via postural strategies, available sensory information, prior experience and environmental context

Question 7

State the four sensory components which help maintain balance

Answer 7

1. Somatosensory (skin receptors)
2. Proprioceptive (muscle spindles / golgi tendon)
3. Visual (eyes)
4. Vestibular (ear)

Question 8

Describe the concept of the inverted pendulum

Answer 8

An inverted pendulum is a pendulum that has its center of mass above its pivot point

Question 9

Define “Centre of mass”

Answer 9

Weighted average of centre of mass of each body segment in 3D space

Question 10

Define “Centre of gravity”

Answer 10

Vertical projection of COM onto ground