Everything i learn, i try to apply to my lifestyle or the way i proceed, even in the smallest things. Well, as a Neurophysiology master, i surely had many things to put to practice, but i had never put some thought on how to improve my abs with that knowledge.
I used to workout my abs with 3 or 4 series of 100 reps, no rest. Each one of those series had 10 different exercises. So, i could say that i had balanced abs, and pretty resistant to fatigue. Not a pro, but ok. Nevertheless, i could never see the "packs". I used to blame on my genes, until i remembered a course on basic neurophysiology. I was introduced to the experiments conducted by Salmons and Sreter, 1976, where they crossed innervations between two muscles with very different morphologies: one with fast, red, type I fibers (the type that sprinters have a lot) and the other with slow and resistant, white, type II fibers (the type that marathoners usually have). It's unnecessary to say the differences in the appearance of those fibers, since the two kinds of runners i mentioned are a good example of it. Well, in the experiment, they cut the nerves that activated each on of those muscles separately, and then substituted the connections. The result is that after some time, the muscles changed the proportions of white and red fibers according to the nerve that activated them. The cause of that was the pattern of action potentials of each on of the nerves.
How did this experiment influenced my abs routine? I decided that, if i wanted my abs to grow like a red muscle, i shouldn't activate it like a white one (little weight for a long time). Instead of training hard, but with 400 reps of 10 exercises i started doing one exercise that activated all the regions of the abdomen, with weight in the ankles (6 kg/12 pounds approximately), and only 10 repetitions, 4 series. Well instead of 400 reps, now i was doing 40. The results can be seen in my pics. In 4 weeks the packs started to show (started on august 2011, and have gotten better since then). And haven't stopped yet.
O. By the way, i don't do cardio, because i'm afraid to lose weight (i have that in my genes). So, the abs shown here were not a result of fat burned by cardio exercises. It was only the abs activation that made the change (and, of course, lifting also burns fat). I hope you find this useful.
If you want to know more details on the specific exercise i used, just ask. This is not the point of this post. Just know that the pattern of activation change the proportions of fibers within the muscle. Good luck to all.