Balance and Stability

Define Balance & Stability

• An objects ability to maintain a stable position

• The area around the contact points with the ground. The larger it is, the greater stability a person has.

• Base of support contributing factors

• The point at which all parts of an object are equally balanced

A body is in balance and stability when:

• Centre of gravity is low

• Line of gravity falls within base of support

• Centre of gravity is over the base of support

• All of centre of gravity, line of gravity and base of support are in one line vertically

Are these people most likely to be stable, unstable, balanced or unbalanced?

• Stable

• Unstable

• Balanced

• Unbalanced

Define Base of Support

• An objects ability to maintain a stable position

• The area around the contact points with the ground. The larger it is, the greater stability a person has.

• Base of support contributing factors

• The point at which all parts of an object are equally balanced

Define Centre of Gravity

• An objects ability to maintain a stable position

• The area around the contact points with the ground. The larger it is, the greater stability a person has.

• The point at which all parts of an object are equally balanced

• Base of support contributing factors

What are the three factors in stability and balance? (use all lower case letters)

Why is stability and balance so important in sumo wrestling?

• Because you are simultaneously trying to execute a skill (pushing) while your opponent tries to push you out of stability

• Because the wrestlers are big and can easily knock you out of the ring with their low centre of gravity

• Because the wrestlers are big, have a naturally high centre of gravity so need to adjust by having a wider base of support and lower centre of gravity

When a human stands in the anatomical position, where does centre of gravity naturally end up?

• Belly button

• Groin

• Chest

• Between knees

Is this person likely to be stable, unstable, balanced or unbalanced? Why?

• Stable, because he is in the middle of a dynamic movement and his LoG is over his BoS

• Unstable, because he is in the middle of a dynamic movement and his LoG is very unlikely to be over his BoS

• Balanced, because he is in a static movement and his LoG is likely to be over his BoS

• Unbalanced, because he is in a static movement and his LoG is very unlikely to be over his BoS

Why do we place our arms out for counterbalance when we are crossing a narrow beam/rope/platform?

• The larger leg muscles are unable to be used so we use the arms for leverage to bring our line of gravity back inside base of support

• To make our body area wider so the base of support is wider and line of gravity falls within it

• To make our body area wider so centre of gravity naturally becomes lower and the body is more stable

• To utilise force summation to use larger muscles to bring us back into balance