Balance

Question 1

What is balance? (2 definitions)

Answer 1

• ability to maintain body’s position in equilibrium

- ability to maintain the body’s center of gravity over the base of support

Question 2

what is center of gravity?

Answer 2

hypothetical point at which body’s mass appears to be concentrated and from which gravity appears to act

Question 3

where is COG located?

Answer 3

slightly anterior to S2 vertebra

Question 4

what is the base of support?

Answer 4

the perimeter of contact area between body and its support surface

Question 5

how does someone fall?

Answer 5

when the COG goes beyond and outside of the BOS

Question 6

What are the systems which work together to maitain balance?

Answer 6

• sensory systems: provide sensory input on whether someone is balanced or not
• integrating system: sensory input is processed and integrated
• motor output: integrating system sends information to motor areas of the body -> decide if any motor activities are required to maintain balance

Question 7

What are the 3 main areas for sensory input?

Answer 7

• visual system
• vestibular system
• somatosensory system

Question 8

What is the role of the visual system?

Answer 8

tells us about:

• relative position of head and body in space
• direction and speed of movement

Question 9

What is the role of the vestibular system?

Answer 9

receptors in inner ear tell us about

• our head position
• movement and acceleration (with respect to gravity and inertia)

Question 10

what is the role of the somatosensory system?

Answer 10

• provide info about proprioception
• > where your joint position is in space
• > sense of limb movement

Question 11

where in the brain is sensory input integrated and processed? (3)

Answer 11

• cerebellum
• basal ganglia
• supplementary motor area

Question 12

what are the 3 main motor output responses for maintenance of balance?

Answer 12

• hip strategy
• ankle strategy
• stepping stategy

Question 13

what happens in the hip strategy?

Answer 13

• pelvis moves in opposite direction of sway/fall

- for larger and more rapid displacements

Question 14

what happens in ankle strategy?

Answer 14

• ankle either dorsiflexes/plantarflexes on the opposite direction to fall
• usually used for small and slow displacements (used rather to maintain balance than prevent fall)

Question 15

what happens in stepping strategy?

Answer 15

• a step is taken either forwards/backwards (opposite to direction of displacement)
• usually occurs when COG displacement is too big to use ankle/hip strategy to maintain balance
• works by increasing BOS

Question 16

7 causes of impaired balance

Answer 16

• lower limb pathology (decreased muscle strength and flexibility)
• spinal pathology (affects motor nerves which slow down motor responses)
• visual deficits
• vestibular system conditions/injuries
• brain injuries
• neurological conditions (decrease central processing of sensory info)
• ageing (older people have less balance due to change in soft tissue, mechanoreceptors and reaction time)

Question 17

definition of balance training

Answer 17

• an exercise programme which requires patients to maintain balance during static and dynamic activities which progressively get more difficult

Question 18

what are the benefits of balance training (7)

Answer 18

• improve balance measures
• reduce risk of injuries due to falls
• improve strength
• improve posture
• improve physical functioning (eg: increase walking speed by decreasing fear in falling)
• improve standing balance and locomotor performance in elderly
• improve quality of life

Question 19

11 ways to progress balance training

Answer 19

• supported -> unsupported
• bilateral -> unilateral
• large BOS -> small BOS
• PWB -> FWB
• stable -> unstable surface
• visual input -> no visual input
• static -> dynamic balance
• add limb and head movements
• add distractions
• give perturbation
• move outside BOS

Question 20

what are the contraindications for balance exercises?

Answer 20

• when can increase pain/inflammation
• when will disrupt healing process/surgical repair
• when patients are inherently unsafe in balance-challenged positions

Question 21

what happens (physiologically) when someone carries out balance exercises? (3)

Answer 21

• decrease in cortical brain activity, but increase in subcortical brain activity (increased skill acquisition)
• decrease in excitability of spinal reflexes (decrease in unwanted reflex joint oscillations -> throw someone even more off balance)
• improved movement control and more refined balance (muscle activation controlled more by brain centers)

Question 22

what are the outcome measures/tests used for balance

Answer 22

• berg balance scale
• functional reach test
• timed get up and go test
• 10m/any distance walk test