It might be true that the abdominal area poses the greatest problem when it comes to losing excessive fat tissue and strengthening the muscles. This is surely because this area is meant to store the excessive fat tissue. Whatever the case, there are several exercises for this region meant for those who cannot be called beginners anymore.
Crunches are always a good thing, regardless of the level of the practitioner. If simple crunches are not a problem anymore, then certain variations should be tried out. For example, hands should be positioned behind the neck with elbows opened, not close to the head. This creates additional strain and requires more strength in the entire torso and abdomen. Also, there is a difference in intensity caused by different speed of performing the exercise. If crunches are performed slowly and with the pause while torso and legs are up, this variation consumes much more energy than any other. Also, additional weight may be used, usually placed on the chest.
Hanging leg raising is another interesting and hard to do abdominal exercise. This requires using a pull up bar. A practitioner literally hangs with holding the bar with hands and legs are relaxed. From this position legs are raised either straight or bent in knees. They are raised up as much as possible, until the thighs touch the torso. An interesting variation includes raising legs and keeping them up as long as the practitioner can hold.
Another intensive form, though very difficult to perform, refers to so-called abs jumps. A practitioner is on the stomach with hands behind the neck and stretched legs. All that is needed is for entire body to jump up while parallel to the floor. Of course, the entire body is needed to be active for this, but contraction of the abdominal muscles is very intensive and responsible in high percentage for the successful performing of this exercise. Even though it always seems non-compatible, muscle mass building should be crossed with some cardio workout, for example, running once a week is excellent for fat burning but also for additional toning of the muscles, the abdominal and others.