Do it more often for better and super-quick results. Try to repeat it at least 5 times. For some people it takes more time to keep their abdominal muscles tense.
Once the muscles adjust to the exercise, you will need much less effort to do it.
Follow these instructions and enjoy tightening your stomach:
1. Initial position -- Lay on your back and keep your arms next to your body. Bend your knees and relax your muscles. Exhale slowly and release the air from your lungs. Your muscles should remain relaxed.
2. Start sucking your stomach in. Do not breathe while doing so. Keep your stomach in that position for 10-15 seconds. Take a small breath and keep sucking it in.
3. Breathe slowly and do not rush to relax your stomach muscles. Suck your stomach again and hold your breath for another 10-15 seconds Inhale, and keep your muscles tense. Take a short breath if you cannot hold in such position for long.
4. Exhale, and relax your stomach muscles. Release the air from your lungs and suck your belly in as much as you can.
You should feel some tension in your stomach muscles. Relax your stomach, but you should not inhale while doing so. Breathe.
In just 3 weeks, you will strengthen your internal abdominal muscles and shrink your waist. This exercise will also give you a better physical appearance.