1. Tap the add button. 2. Upload a file of a picture of a person in an action shot from any sport you choose (preferably one where they are touching the ground). 3. Use the label and drawing tools to add 3 labels to your picture showing the Centre of Gravity (COG) of the individual, their Base of Support (BOS) and the Line of Gravity (LOG). 4. Then use the microphone to explain whether the person is stable or unstable. Be sure to justify your answer by referring to COG, LOG and BOS. 4. Tap check to add to your portfolio. See an example below.