Abdominals
The key to getting a flat stomach has two major components:
1. Strengthen the abdominal muscles
This is the obvious part. You need to have a strong set of core muscles in order to your six pack to show. Stronger muscles also "pull in" your stomach. Don't think that having stronger abs will make your waistline get bigger. The opposite is actually true. The stronger the muscles, the tighter your stomach will look.
2. Lose excess body fat
This is the part that many people overlook. Doing hundreds of ab workouts eachnight will definately strenghten your abs, but if you have a layer of fat over it, no one will ever be able to see all of your hard work. A general estimate of what your body fat should be to see your abs is around 8-10% for men and about 18-20% body fat for women.
So how do you lose that body fat? The best way is cardio exercises. Running for over 20 minutes is a great way to lose body fat. The reason you must run for longer than 20 minutes, is because the first 20 minutes of running your body undergoes anaerobic respiration. This basically means that your body is burning off its stored energy, and it take approximately 20 minutes for it to use this up. Thats when it starts tapping into your fat for energy, so make sure your workout is at least 20 minutes, preferably more. Slow long distance runs are better than shorter faster ones.
Combine these two steps and your are well on your way to flatening your stomach. To see some of the most effective abdominal exercises, click on the links to the different exercises.