The Importance of Ab Workouts

If you think you can get away with just working out your chest or biceps, or think that just cardio is good enough to avoid having to do any abdominal workouts, then you are just doing wishful thinking. While it is true that your abs are engaged in nearly any workout or exercise, it is this very reason that makes doing specific ab workouts all the more important. When you workout your abs, your are in essence improving your overall strength and conditioning. Whether you are running outside or doing heavy duty squats, your abs work as a way of "holding" your muscles together. Thus the stronger your abdominal muscles are, the stronger your overall body strength is. This also makes it important to perform some ab workouts every day, even if they are simple crunches. Because if even walking requires some abdominal strength, thus every day requires some abdominal training. Thus where ever your body takes you, your abs will be the underlying force that holds it all together, and this can't be underestimated. 

Source: http://www.bodybuilding.com/fun/franco3.htm