This is from www.truthaboutabs.com:
- You can do them standing, seated (such as in a car), kneeling in a four-point position, or even lying flat on the floor. I prefer them seated or standing.
- The movement is as simple as pulling your belly button in as far as you can by imagining you're trying to touch your belly button to your spine and holding for 10-20 seconds at a time.
- Start by inhaling deeply. Then, as you exhale, start pulling the belly button in towards the spine and hold it there for 10-20 seconds while just taking short breaths. Repeat for several of these 10-20 second holds, perhaps 5-10x if you have enough time while in the car. But even just repeating 3-4x every time you're driving somewhere can really add up over time and give you the benefit of a flatter belly!
- Get in the habit of doing this at least 4-5 days per week while driving somewhere and you may find that this helps to flatten your stomach more by strengthening the transversus abdominis muscle (the deep abdominal muscles beneath the rectus abdominis) if you previously had a "lazy belly."