1. Biomechanical Principles:
STABILITY AND BALANCE

2. Stability = The ability of an object to stay balanced
Review:
Centre of Gravity– where is it on a person? Can it change?
Base of Support– what is it?
Line of Gravity
There are five factors which determine our levels of stability...

3. INCREASING THE SIZE OF YOUR BASE OF SUPPORT
Increases in Base of support can be made by widening the position of the body parts touching the ground eg/ feet when standing or hands when doing a handstand OR
By adding more points of contact to the ground.
Can you think of some sporting and non sporting examples of this??
Example.

4. EXTENDING YOUR BASE OF SUPPORT IN THE DIRECTION OF THE FORCE OR IMPEDING FORCE
Stability can also be increased by extending your base of support in the direction of an oncoming force
Example.

5. HEIGHT OF THE CENTRE OF GRAVITY ABOVE THE BASE OF SUPPORT
The lower your centre of gravity is the more stable the body will be
Example.

6. LOCATION OF THE LINE OF GRAVITY WITHIN THE BASE OF SUPPORT
The closer the line of gravity falls within the centre of the base of support the more stable the body will be.
Where is the line of gravity on these athletes??
How stable are they?

7. BODY MASS
The larger the mass, the greater the stability. Heavier bodies are harder to move and there fore more stable
Can you think of some sporting examples where larger mass may be an advantage or disadvantage?

8. ACTIVITY!

9. Can we apply the principle of stability to the stance phase of our golf swing?

10. Thinking about centre of gravity, base of support and line of gravity, explain how you could improve this sprinters starting position