Not only are most traditional ab workouts a waste of time, but they also slow your fat loss efforts. Each workout you spend crunching takes time away from more effective fat loss methods - such as interval training.
That's right, the common man's (and woman's) ab workout taken from Shape magazine or Muscle'n'Fitness often hurts their fat loss program more than it helps it.
Remember - I'm in the business of getting you the most fat loss in the least amount of exercise time...so I have little room in my
program for traditional ab crunches (with the exception of using
basic ab exercises for beginners who need to learn to use their ab muscles after a lifetime of inactivity).
Instead, I focus on exercises that build a 6-pack AND burn a lot of calories at the same time. That's why I'm a big fan of making EVERY exercise an ab exercise (by bracing the abs in every movement), as well as using total body ab exercises (such as Mountain Climbers, the Spiderman Lunge/Climb, and the Stability Ball Jackknife).
These exercises use far more muscle mass than a traditional crunch. In fact, some of the total body ab exercises are "interval-like" in nature, helping to put more metabolic turbulence on the body, and as you know, that's what burns calories during AND after the workout.
Now of course you know that you can't spot reduce the fat on your body - so doing an endless number of crunches not only does little for you in terms of losing fat, it also wastes your time in your quest for a 6-pack.
Here are a couple of strategies to maximize your workout time when your goal is to get lean, and get down to a low-enough body fat percentage to see your abs in as little workout time as possible:
(If you've got 2 hours a day to workout, by all means, do whatever your heart desires...but I don't think many of us that live in the real world have that kind of time.)
A) First, simply cut back on your ab training - If your goal is to
simply lose fat, gain a little muscle, and just look as good
possible, then you can't spend 30 minutes on abs everyday. You can build your 6-pack by doing less than 30 minutes of ab exercise per week.
I'm convinced that no one (not even a fitness model or pro
bodybuilder) needs more than 30 minutes of ab training per week.
In fact, at the photoshoots I supervise for the fitness magazines,
I get to talk to a lot of fitness models and what they tell me
about their training routines might shock you. Most of them don't train nearly as frequently as you or I might think.
Instead, they've worked hard over the years with the basic lifts to build their body, and now many of them simply use nutrition and maintenance workouts to keep their abs showing.
B) Second, replace your crunches with the total body ab exercises I mentioned earlier. Also, if you have access to a cable machine, you can do weighted ab exercises such as kneeling cable crunches.
C) And finally, if you are doing intervals for fat loss as I
recommend, you can use the following approach to increase the
difficulty of your ab and interval training. However, this is an
advanced method only. Beginners should stick to the TT guidelines in their manual.
During your interval workout, perform an ab exercise during your active recovery period. For example, if you are doing running intervals on a treadmill...
Run for 60 seconds at your work interval speed. Immediately stop the treadmill, get off, and go into a set of 20 Mountain Climbers. Climb back on the treadmill and start it up for your next interval. Repeat for 3-6 intervals.
You can also use basic spinal stabilization "ab exercises" such as
the plank, side plank, or advanced plank versions (i.e. plank with your arms on the ball) to train your spinal stabilization while under heavy breathing stress. I learned this technique from Dr. Stuart McGill.
Remember: Always train safe, with good form, and be conservative. Don't try to be a hero in the gym, but you should safely challenge yourself in each workout.
Stick to the Turbulence Training Guidelines if you don't know where to start.