I have bad news for a lot of people who stare at the gorgeous abdominal muscles (aka the six pack) that the hollyweird show off on the silver screen, the boob tube, or anywhere else they tend to show them off. That either took a lot more hard work, or a lot more special effects than just doing sit ups will provide to the rest of us. This in no way means that it is hopeless, but until someone actually explains to most of us how to achieve a six pack, we all are pretty much in the dark. Most of us are just getting frustrated because we do it all wrong for so long, and a few tweeks are all it takes to get it right.
Now keep this in mind, but a hollyweirdo will take on a role that requires abdominals and then they go out and get a fitness guru to monitor everything they do, for a certain amount of time, and then an artist will go in there and shade it all properly to make it all that much more profound. Well we can’t do this (unless you marry an artist like I did, um, not that I would paint the stomach) especially the part about taking a month off from work to do nothing but work out. Fortunately I give you the great news that you can stop doing the wrong things and get your abs looking pretty damn good, if not perfect.
First: You might as well start on this while you do the rest, but nobody has a great six pack if their body fat is above 12%. The average person carries a body fat well over that and no matter how much you do for your abdominal muscles a good layer of fat is like spreading asphalt on a roof. It covers all of the cracks, and by cracks I mean the lines between your abdominal muscles that give them definition. People hate this part, but it will require a diet and an exercise program that works outside of the abdominal region.
Second: Most people (been here) think that the abdominals aren't like other muscles. They are and they require the same work / rest period that all muscles do. If you are banging away at your abdominals every day, then they have given up on you and are not going to gain any definition. Most of us that are in the know do a workout schedule that will work your abdominals every other day. Mine for example would be Day 1: Back and Shoulders, Day 2: Lower Torso (abdominal, lower back, oblique) and Legs, Day 3: Chest and Arms, Day 4: Lower Torso and Cardio (treadmill, exercise bike, etc) and you will note that my legs basically get two days this way too, but never two days in a row.
Third: This is where people who do the first two still fail most of the time, is in they don’t have distinct abdominal exercises that work both the upper abdominal and the lower abdominal. Yes, where the upper abdominals will work the upper half of the body (sit-ups) the lower abdominals will work the lower half of the body (leg lifts). This is where I always try to tap someone on the shoulder, if they do a bazillion sit ups and still have a pooch at the bottom of their abs. The frustration is killing them just like it did me, and just like with me a tap on the shoulder and the advice of “leg lifts” puts them back on track and happier with their workouts in a few short weeks.
Now here is what would constitute a complete “lower torso” workout, and if you do all of these things (starting slow, and increasing slowly week to week) while bringing your body fat down, you can have a ripped mid section. I always start with my lower back because I have a bad lower back and it will often determine how the whole routine will go.
Bar Twists – Placing a wooden bar on your shoulders with your arms spread across the bar. Use a bench to keep your legs in the same position. Standing you would slowly twist from the right then to the left counting each side. People will tell you that this doesn't do anything, and is bad for you. Tell them to not do them and continue doing it. You actually can feel the burn in your mid section by sucking in your stomach, but you don’t need to do that. It just works. When you get to the point that you can do 50 of these, just stop there, and do it at that amount every time.
Back extensions – You can do this with the lower back machine at most gyms or you can do it without weight using a hyper-extension stand. If you are using weight stop at 12, if you aren't using weight stop at 20.
Crunching – Either do this on a machine at your gym, or do it with your back flat on the floor, and your calves up on a bench. Your upper thighs will be at a 90 degree angle from your back. If you use weight stop at 12, if you aren't using weight do as many as you can.
Leg lifts – Using a Roman Chair, or hanging from a chin up bar, bring your knees up into your chest for as many as you can. When I started I could only do about 3 or 4, it gets better every week. Don’t quit on these.
When you are finished, you do it all again. Start with two sets, after a week or so do three sets, and after you have that down do four sets. When four sets seems pretty easy, just add an extra exercise or even two or three in there until you realize that your lower torso routines are taking over an hour. You've reached my level at that point and in my opinion that is pretty good.