I repeat, more ab exercises do not mean better ab definition.
I would estimate that at least 90 percent of the most frequent gym-goers desire to have a flat stomach with some type of visible abdominal definition. And those who do not frequent the gym as often probably have an even greater desire for this achieved aesthetic because they are likely further from the goal. Sadly, 100 percent of both groups are spending too much time doing conventional ab routines like crunches, sit-ups, and toe-touches hoping to acquire a better looking midsection. In most cases, these isolated abdominal exercises do not result in a better-looking core.
Despite what you see in the mirror the fact of the matter is that we all have abs. It's just that some people's are hibernating in the cave of a belly they have created by either a lack of exercise, the wrong exercises, poor dieting choices, or some combination of the three. Unless you are a male with a body fat percentage below 12 percent or a female with less than 20 percent, doing the conventional ab routines previously mentioned will not help you reach your goal.
It may be gratifying to feel your abs burning and slightly tightened after completing 500 sit-ups during a workout, but by the time you've left the shower that sensation has most likely left with you, and your stomach isn't any closer to the way you want it to look.
In order to have a flatter belly and/ or visible abs, it is more important to focus on an overall weight loss strategy rather than working on isolating your abs directly. The workout should be tailored towards lowering your body fat percentage before you worry too much about sculpting the core with sit-ups and crunches.
Think skinny before sculpting.
In the perfect world this would mean doing a combination of cardio and strength training at least five times per week, and strictly monitoring your daily caloric intake. But we don't live in a perfect world and doing everything right all of the time is not realistic for most normal people with extremely busy lives.
In order to more efficiently and realistically bring you closer to the goal of having a flattened stomach, think caloric expenditure first when making your exercise selection. In other words, focus on spending the majority of your time doing exercises that are going to burn a lot of calories like squats, lunges, pull-ups, or any of the other exercises we like to avoid because they make us out of breath.
With limited time to workout and limited discipline to follow a perfect diet, there are two rules two follow during each exercise session:
1. Target the biggest muscles first and most often.
2. Work as many muscles during each exercise movement as possible -- also known as compound exercises.
Again, if you're not already in the appropriate body fact percent range, focus on slimming off through caloric expenditure. Working the biggest muscles of the body are going to help you with this. These muscles are in the legs (hamstrings, gluteus, and quadriceps), the latissimus dorsi in the back (lats), and the pectoral muscles of the chest (pecs). Concentrate on those muscles first in order to maximize the amount of calories burned during exercise.
Additionally, the more muscles you are moving at once the more oxygen you are burning and the more energy required to complete the exercise. That is why I recommend compound exercises in order to achieve abs. Compound exercises are great because not only do they work the biggest muscles but, they will also burn the most oxygen and push your heart rate into the fat burning zone. The more fat that you burn, the more likely you are to lose weight and get closer to having a six-pack.
Nevertheless, there is a time and a place for conventional ab routines like sit-ups. Include them as active rest during a circuit or superset. Work them in-between your sets of squats, dead lifts, and bench press. For example, after you do a set of squats, rather than checking your text messages or switching to a different song on your workout playlist, do the crunches. This will keep your heart rate up for fat burning, enable you to exercise your core in isolation, and be an overall more efficient workout.