Vacuuming your stomach is a great way to define the boring abdominal part of the body. The best thing is that this exercise is not difficult and hard to perform at all.
As Kristen shows, the process of performing this exercise is quite simple. First, you need to take full breath and fill your lungs and abdomen with air. Next thing you need to do is to aggressively exhale all the air in order to achieve more concave belly profile.
This is also a great way to improve your body posture.