A Rockport Walk is a method of calculating your respiratory fitness. To complete the test, you need to walk a mile as fast as you can, recording the time it takes to complete and your heart rate as you complete the mile. You will also need your weight (in Kg or Lb). When you have the required information, simply input the figures into the app then press calculate. This will give you your estimated VO2 Max. The higher the better. For comparison charts of your VO2 Max, charts are readily available on the internet.