To lose weight in the belly or get a flat stomach see twenty diet plan not just enough to do toning exercises to strengthen the abdominal muscles, although these are also important, but there is to do aerobic exercises to burn fat.
Specific exercises for abdominal muscles get strengthen and tone them with it, you will notice that the muscle are hard and strong, but will not be visible if above them, is certain layer of fat. For this reason it is necessary to combine the exercises shown below with aerobic exercises running, walking, swimming, cycling, tennis, etc
The training plan is based on making 3 or 4 days a week of aerobic exercise for about 45 minutes and after 20 sessions of crunches a 2 or 3 reps and then go progressively increased.
There are many ways to engage your abdominal, as can also be done right or wrong. It is advisable to perform them in the position shown in the picture, you have to keep your head straight in line with the trunk and not bend the neck to prevent overloading, the lower back must rest firmly on the floor to avoid working the posies and work only abs.