The cause of falls and why older people are more at risk Flashcards
Define balance?
The ability to maintain the line of gravity passing through the centre of gravity (COG) within the base of support (BOS)
Define Centre of Gravity (COG)?
Point in space where total body weight is concentrated/acts
Where is a person’s COG located?
Immediately anterior to upper sacrum
Define line of gravity?
Imaginary vertical line passing from the centre of gravity of an object down to the ground
Define Base of Support (BOS)?
Area beneath object/person that includes every point of contact they make with the supporting surface
Do contact points of BOS have to be body parts?
No
Contact points include body parts eg. hands, feet and inanimate objects eg. crutches, chair that person is sat in
Define stable vs unstable balance?
Stable balance: Line of gravity is inside BOS
Unstable balance: Line of gravity is outside BOS
Define postural sway, and what is its function?
Horizontal balance-seeking movements around COG
To correct unstable balance by moving body so that line of gravity is inside BOS again
In forwards postural sway, what balance-seeking movements occur, and what is the position of the imbalanced, unstable person?
Movement to pull COG back and down
to correct forwards and upwards imbalance
In backwards postural sway, what balance-seeking movements occur, and what is the position of the imbalanced, unstable person?
Movement to pull COG forward and up
to correct backwards and downwards imbalance
Describe the ankle strategy for correcting forwards and backwards postural sway?
Muscles on front of ankle contract to pull COG forward in backwards sway
Muscles on back of ankle contract to pull COG backward in forwards sway
When is the ankle strategy used to correct postural sway, in terms of the line of gravity and BOS?
For ‘small’ imbalances, when line of gravity is still within BOS and is being maintained
Describe the hip strategy for correcting forwards and backwards postural sway?
Hip joints quickly extend and arms extend up and forward (limbo position) to correct backwards sway
Hip joints quickly flex and arms extend up and back (‘bow’) to correct forwards sway
When is the hip strategy used to correct postural sway, in terms of the line of gravity and BOS?
‘Medium’ imbalances where line of gravity/COG is at edges of BOS
Describe the stepping strategy for correcting postural sway?
Take steps to change position of feet and establish new BOS which line of gravity will now fall in
When is the stepping strategy used to correct postural sway, in terms of the line of gravity and BOS?
‘Large’ imbalances where line of gravity/COG has exceeded past BOS
Describe the reaching/grabbing strategy for correcting postural sway?
Reaching out and grabbing anything nearby to prevent falling down
