i do abs max twice a week, but some people do it every day. i think it just depends on the person.

I do abs twice or three times a week max, as they should also get worked through the various compound movements as well.

I work mine every other workout - to EXHAUSTION! Couldn't imagine working them the next day - too sore still.

See that is what I figure too. It is a muscle just like all the rest and need the same amount of rest. But the argument started because a client of mine bought the training book from musclestuff.com and in the training section it lists abs every day with every workout. I said i didn't recommend it and she said this is muscle and fitness they can't be wrong. So I was just curious on all your opinions.

This is a good question. The abs have alot of type 2 muscle fibers, so they recover pretty quickly but worse, they atrophy fast too. So I like to cross-train my middle, allow for sufficient rest, but not quite as long as other mucle groups. I believe you could train your abs 5-6 days a week without overtraining, but you have to define your goal.

If you are trying to develop the actual muscle size, you could train them heavy, with lots of rest like other muscle groups, maybe 2-3 d/w with weighted machines, cable crunches, decline sit-ups, etc. But I don't think heavy work is neccessary for the majority of the time. The abs are structured to work as part of a team with your lower back and pelvic muscles. They are intended to help support your spine, that's it.

IMO, the smartest and most effective way to train your abs, is to train them in conjunction with your other core muscles, frenquently (4-6 d/w) with lower resistance but higher reps. Lots of twisting, throwing, crunching, leg raising and swiss ball exercises would be nice. With all the different muscle structures in the abs (transverse, rectusA, In/Ext obliques) they need plenty of cross training exercises like the ones above, to achieve balanced development. This functional type of training is not only key in reducing low back injury, it will also "develop" the abdominal 6-pack just like conventional heavy work IF your BF is low. People who compete have one goal in mind when it comes to their abs, they want them very lean and defined. 90% of this is attained through diet and cardio, not any specific ab routine.