Don't do ab work every day, just don't
Ab work. Training the core. Building a 6-pack. Whatever you want to call it, training the abdominal muscles has been corrupted over the years. I’ll be short with this one and just get to the point: you don’t need to do a lot of ab work for your abs to look good. In fact, too much ab work will make the abs bigger, and this will only give you a thicker waist. Don’t believe me? Look at Britney Spears at the beginning of her career (on the left) and then compare that to the more recent picture of her (on the right). She’s lean in both pictures, sure, but her waist looks a lot bigger today than it did at the start of her career. The reason: she started doing 1,000 crunches a day to try and sculpt a tighter midsection. It only made her abs bigger, which on her tiny frame made a noticeable difference in the size of her waist.
The abs are not a muscle that needs to get bigger. They just need to be strong enough to prevent injury on heavy free-weight movements.
The abs have two purposes: to stabilize the spine and prevent it from buckling under pressure, and to curl the hips up a few degrees. Proper abdominal training should focus on the former, which is stabilization, and can eventually include hip curling movements like leg raises on an inclined bench or in a hanging position, but mostly it should be stabilization. Good movements to train the abs for stabilization are any variation of the plank exercise, ab-wheel roll-outs, squats and dead lifts.
Charles Poliquin, author of several books on weight-lifting and a highly regarded fitness professional, said, “If you truly isolate the abs, after six to eight weeks an athlete will plateau the rest of his life. Research has shown that the most coordinated athletes master the most difficult abdominal exercises in six to eight weeks. The only things that increase abdominal improvement are squatting and dead lifting.”
So, the ONLY way for the abdominals to continue to improve is with heavy squats and dead lifts, which shows you what the true purpose of the abdominal muscles are.
I hope this clears things up for you regarding ab training. Don’t train your abs for hypertrophy (muscle growth), train them with mostly stabilization exercises and only to the point of being strong enough to do heavy squats and dead lifts injury-free.
One last point: unfortunately, the only way you’ll ever enjoy the fruits of your labor is if you are lean enough to see your abs, as they can quickly get covered up by fat. This can only be accomplished through diet and exercise, so start eating better and get moving!