
Originally Posted by
Triple X
The main abdominal muscle, the rectus abdominis, is one continuous muscle that connects at the base of the rib cage and inserts at the pubic bone. Your rectus abdominis does not contract like a hinge. If you could lay it out on a table and watch it contract, it would roll up. This is why the traditional sit-up is a waste of time. With a sit-up, your abs stay flat; they don't roll up. Sit-ups predominantly work your hip flexors.
The abdominals, intercostals and obliques, the muscles that comprise your midsection, are muscles, and should be trained as such. Concentrate on the quality of the reps being done, not the quantity. Forcefully contract your abs at the flexation point of each rep.
Regardless of how hard you work your abs or how strong they become, excess body fat will keep them hidden. You need to maintain low body fat through sensible diet and cardiovascular work.