I was recently invited by Insider magazine as an expert to contribute to an article on the core vs the abs. If you have been confused about the core and the abs, read on to find out what I said!
I am Dr Susan Baxter (PhD) and I am a fitness and nutrition educator for personal trainers and allied health professionals. I also work with my own online clients and have helped over 500 people reach their goals over the last 16 years.
The core vs the abs is quite different. The core is the middle third of your body, including your back, abs and even your glutes. But the abdominals are 3 areas: obliques (internal and external), transverse abdominals and rectus abdominals.
People should be actively working their abs frequently, and I would add a small component of abs into every workout (approx 10-20% of a workout); however I would be suggesting a few alterations to what you may expect. (all of course should be cleared by your physio or health professional first if you have been pregnant before).
One being that you can get fitter which allows you to do more work in your workout; but to do that you need to be working out at a suitable intensity for this. If you do an adequate amount of exercise of your body you will adapt and get fitter which then means to keep progressing you need to do "more" volume or frequency or difficulty of exercise.
With that being said it means that if you are constantly fatiguing your abs you won't be able to do as much volume of work for the rest of your body as your abs being fatigued means it's harder to lift heavier to increase your workout difficulty. This is why I recommend a little bit most days.
Another lesser known fact is that if you often fatigue your abs then you may find yourself constipated!
The benefits of training your abs are that you'll have better posture; better strength for other exercises. Plus they will be more prominent at lower body fat percentages.
If seeing abs is your goal it requires: bigger and muscles (from training them), and lower body fat which is a combination of better nutrition and getting the heart rate up doing exercises that include more than just your abs. Ab exercises alone don't burn many calories and you can't spot reduce the fat away from your abs without losing it from all over. So it does need a combined approach.
Isolation exercises (like crunches) can be triggering for people who sit a lot or have back pain. They also may be wise to avoid if you have abdominal separation from having a child too (make sure to consult a womens health Physio so that you aren't separating the abs more).
Furthermore training your abs with just crunches can make your abs looks like your abs aren't flat but more "dense" and bigger in your midsection.
Working out different parts of your abs would be difficult as you tend to engage abs from different angles; but the principles of letting the abs rest from workout to workout is great.
Try abdominal exercises that elongate the abs (like crunches on a Swiss ball, and side crunches on a Swiss ball). Don't aim for range focus on feeling the abs working (which requires slower movements but higher rep ranges, such as 20, and do 3 sets). I also like to include with my bikini athletes some ab "vaccums" to get the breathing and feeling right before using the Swiss ball. Then include exercises like the plank and lifting challenging weights with correct form and you'll engage your transverse abdominals more.
Hope that was interesting to you and clears up a few things! See you next time!