Stability and Balance Flashcards
Define Centre of Mass?
The CONCEPTUAL point where all the mass of a body can be considered to be concentrated
=the average weight of an object
Centre of mass
vs
Centre of gravity
COM
- distribution of MASS is equal in all directions
-doesn’t depend on gravitational field
COG
-distribution of WEIGHT is equal in all directions
-DOES depend on gravitational field
Define balance?
The ability to control equilibrium ( a state of zero acceleration)
Achieved and maintained through stability
COG must be above and IN base of support
Define stability?
The tendency of a body to remain and return to its initial position “following the application of force”
Can be PASSIVE vs DYNAMIC
What is PASSIVE stability dependant on?
(Wilson, Ate, Horrid, Henry)
Weight
Area of base of support
Height of COG from base of support
Horizontal distance from COG to pivot point
(bigger distance= greater stability)
Define “stable equilibrium”?
-potential energy at a MINIMUM
-lots of work must be done to change
-tendency to return to original position
Define “unstable equilibrium”?
-potential energy at a MAXIMUM
-very LITTLE work needed to change
-small movement= outside BOS
Define “neutral equilibrium”?
-object does move but there is no change in potential energy
eg: a ball
Explain the concept of an inverted pendulum?
Something that is free to swing, but you are trying to control and balance it upright
Much like a human- large head and small, thin body
What is ACTIVE stability dependant on?
LOM
Laugh
On
Me
EB
SG
1.Keeping COG over BOS
2.Lowering COG
3.Increasing mass
4.Extend BOS towards oncoming force
5.Shift COG towards oncoming force
Common reflex mechanisms within humans to remain balanced?
- Ankle strategy- extend at ankle and push back
- Hip strategy- extend at hip- greater movement of mass
- Stepping response-movement
- Arm Circle-apply momentum in opposite direction
