I always been told how important of keeping balance of body during my WingChun training  session, so I started to understand the  basic theory of Stability and the centre of gravity.


The direction of the force of gravity through the body is downward, towards the centre of the earth and through the COG. This line of gravity is important to understand and visualise when determining a person’s ability to successfully maintain Balance. When the line of gravity falls outside the Base of support (BOS), then a reaction is needed in order to stay balanced.

When the line of gravity is within the BOS, an object or person is said to be stable. When the line of gravity falls outside the BOS, the object or person is said to be unstable. Given that the line of gravity must fall within the BOS in order to satisfy the criteria for stability, the following factors should be considered:

  • A larger BOS increases stability (the line of gravity must move a greater distance to fall outside the BOS)

  • A lower COG increases stability (it’s unlikely that the line of gravity will fall outside the BOS)


According  to these research I decided to build up a prototype around Centre of Gravity.

I thought it might helpful for student who interest in martial arts to understand every movement and the meaning of  behind.


For my tribe, the first idea is Roly-poly toy(tumbler)which rights itself when pushed over.The bottom of a roly-poly toy is round, roughly a hemisphere. Many roly-poly toys are hollow, with a weight inside the bottom.