Principles of Stability

1. Every body continues in its state of rest or of uniform motion in a straight line except insofar as it is compelled by forces to change that state.

2. The acceleration of a body is proportional to the force causing it.

4. Stability is directly proportional to the area of the base on which the body rests.

5. Stability in a given direction is directly proportional to the horizontal distance of the center of gravity from that edge of the base toward the given direction of movement.

6. Stability is directly proportional to the weight of the body.

7. Stability is indirectly proportional to the distance of the body above the base.

8. For equilibrium to exist, the center of gravity of a body must fall within its base.

9. To start quickly in one direction, keep the center of gravity as high as possible and as near as possible to the edge of the base in the direction of movement.

10. For greatest immobility or stability, increase the area of the base and lower the center of gravity as much as is consistent with the activity involved.

11. To stop quickly when in rapid motion, spread the base and drop the center of gravity as low as possible consistent with subsequent movements.

12. A body is in equilibrium when its center of gravity falls within its base. It loses equilibrium when the center of gravity falls outside of the base.

13. In all arm support activities, the center of gravity of the body should be as nearly as possible over the point of support. (the hands)

15. If a performer is in the air free of support, the height to which the center of gravity can be raised above the floor cannot be effected by body movements, but the position of the center of gravity within the body can be changed and the body may be lowered or raised above the floor by the movement or change in position of a member of the body.

27. When a limb is used to turn the body of another, the individual turned must resist the force of the thrower by moving the limb against the force.

31. In throwing or pushing activities, one or both feet are kept in a firm contact with the ground until the object is released in order that the total effect of the effort may be in the direction of the throwing force.

36. Mounting movements in swinging exercises should usually start as the center of gravity passes a point directly below the point of support.

45. The spin of an object produces a stabilizing effect upon it.

46. The reaction of a spinning object after impact with a wall or a stationary surface is dependent upon the direction of spin.

49. In jumping activities, the depth of the crouch or the angle formed by the femor and the tibia is directly proportional to the strength of the muscles.

50. A muscle contracts with more force when first put under stretch.

53. Twister movements which are started before the body is air-borne will be in the direction of movement of those members of the body which are used to create it.

54. Twister movements which are started after the body is air-borne will be in the opposite direction to the movement of the members of the body which are used to create it.

55. Forward rotation is faster when a twister is brought into the movement.