Abdominal Anatomy 101- Part 4/10 of How to Sculpt a Flat Belly

Now that you’ve learned the basics of eating for fat loss, it’s time to discuss the fun part: how to exercise to build better abs.  In today’s lesson, I’ll tell you how to build up your abdominal muscles.  Tomorrow we’ll talk about how to burn belly fat. 

First off, there are two big ab training mistakes you need to avoid.

First, you don’t want to build your abs too big and bulky.  Excessive growth can give you visible abs, but also cause them to bulge outward.  This is particularly an issue for women, since excess size can give the abs a squared-off, masculine shape.  Good ab training should be more about fat loss than muscle growth. 

Second, many ab exercises are essentially leg exercises that only secondarily work the abs.  You’ve probably felt this before when doing sit-ups.  There are a few “ab exercise” that you need to avoid because they’re really just leg exercises.  I’ll explain how to identify them in a minute. 

Next up, you need to understand the anatomy of your abdominal muscles.  There are four groups of abdominal muscles you need to know about.

First, there’s the rectus abdominus.  These are a set of muscles that run vertically from the pubic bone up to the sternum, on the very front of your abdomen.  These are the muscles that form the sixpack, and the first muscles you probably think of when you think of abs.  The main function of the rectus abdominus is to flex the spinal column, as when you perform a sit-up or crunch, but they’re also used somewhat in side-bending motions and to stabilize the trunk.

Exercises for the rectus abdominus: all types of crunches as long as the feet are not held in place (more on this later), front plank, captain’s chair, slow myotatic crunch.    

Second, there’s the transverse abdominus.  These muscles lie underneath the other abdominal muscles, so they’re not visible.  They aren’t used to move the torso- their main use is to forcefully expel air.  If you suck in your gut and hold it in, this is the muscle you use to do it.

Exercises for the transverse abdominus: ab suction, either kneeling or on hands and knees

Third, there are the external obliques.  These muscles are on either side of the rectus abdominus.  They aid the rectus abdominus in spinal flexion- bending forward- but their primary purpose  is to rotate the abdomen or bend the torso sideways. 

Exercises for the external obliques: side bends, twisting ab crunch, bicycle crunch

Fourth, there are the internal obliques.  These lie under, and at right angles to, the external obliques.  They are used in all of the same motions as the external obliques, but on opposite sides.  Like they transverse abdominus, this muscle group isn’t really visible.

Exercises for internal obliques: same as external obliques

Finally, there are the hip flexors.  This set of muscles in the hips, base of the spine, and upper thighs is often engaged in abdominal exercises.  In some cases the hip flexors, rather than the abdominals, are actually the prime mover of an exercise.  As mentioned earlier, you want to make sure your abdominal exercises are actually working your abs, and not your legs.  That means there are a few exercises you need to avoid.    

This includes exercises where your feet or legs are held in place while you move the torso- examples include sit-ups where someone is holding your feet down, or incline sit-ups with your feet held in place by a padded bar.  Anchoring your feet like that allows you to contract your quadriceps and hip flexors to move your torso, whereas allowing your legs to float freely- as with a bicycle crunch- prevents this and forces you to actually use your abs.

Note that the hip flexors are also heavily involved in the front plank.  However, they can’t actually take over for the rectus abdominus the way they do in a sit-up, so front planks are still a great exercise as long as you’re doing other ab exercises too. 

So there you have it- the abdominal muscle groups you need to work on, the best exercises for working them, and the few you need to avoid.  Tomorrow I’ll show you how to put these exercises together into a workout, in a way that build your abs (but not too much) while also burning belly fat.