Skinny Abs to Muscular Abs: Build Size and Definition

Find out how to build size and definition by turning your skinny abs into muscular abs.

May 1, 2024

6 min read

Do you have a six-pack or a sticks-pack?

Although you technically “have abs,” even at a lighter weight, skinny abs may not look as good as muscular abs if you’re hoping to put on some muscle mass.

As a part of any aesthetic workout transformation plan, abs are pretty much a staple. Cheese grater abdominals can take your look from painfully average to a Greek God-status physique.

It’s night and day before and after abs.

If you want to understand how to transform your skinny abs into more muscular ones, keep reading.

What are the abdominal muscles?

When we talk about “getting abs” or “having abs,” what do we really mean?

Usually, this refers to your Rectus abominis: the divided six-pack compartment that sits on the front of your trunk. There are several other abdominal muscles, though, that impact the look and feel of your abs and most importantly how they power your body.

Let’s take a look at the key core and abdominal muscles.

Rectus Abdominis

The rectus abdominis or your six-pack is the section of your abdominals that sits between the lower ribcage and pelvis on the front of your trunk.

Transversus Abdominis

The transverse or transversus abdominis is a deep core muscle that sits under your obliques. It wraps around your whole trunk, from front to back.

The main function of your transverse abdominis is to keep your internal organs safe and to hold them in place.

This muscle also helps to support your lower back and maintain the normal tension of your abdominal wall.

Although it’s not as front-and-center as its neighbor rectus abdominis, the transverse abdominis plays a crucial role in many key processes of life.

Obliques

The obliques are the sides of your abs. These waist muscles are what you use when you twist your body from side to side.

Pyramidalis

The pyramidalis is a vestigial muscle. That means it’s evolved to shrink over time and doesn’t hold much of its original function.

Current research suggests that it helps to flex your linea alba, that is, the line the goes through the center of your six-pack.

Alongside these key muscles, we refer to a few other sections of your body as “the core.” This keys confusing since it sometimes ropes in internal organs, back muscles or even stabilizing muscles.

What most definitions mean by core is anything that forms part of the center of your body that connects your upper and lower halves.

Other muscles that can be considered part of your core are:

Diaphragm

Iliocostalis

Multifidus

Pelvic floor muscles

How do you get abs?

We all have abdominal muscles that help us to stand, digest, laugh and speak, but actually having muscles so developed they show through your skin is another matter.

But to get abs that show, there are two key components:

Lose excess fat that covers the muscles: If you are working on the best weighted ab exercises or bodyweight moves to tone up, it’s possible that you already have some considerable strength to your abdominals! That said, you can’t actually see your abs if they’re hidden under a layer of fat.

Increase the strength and size of your abdominal muscles: If you’re in the boat of being slim or skinny with no visible abs, this category is for you. Even with a slim body, it’s possible that you have little to no abdominal definition since you’re not actually growing your muscles.

Now that we understand the two main cases for why you may not have visible abs, let's look at how to remedy them. These are some strategies you can use to both reduce visible fat that covers the abs and build the muscles so they become more prominent.

Decrease body fat

If you’re a heavy person, you may actually have strong abs that are in hiding!

Carrying more fat on your body covers your muscles and hides some of the definition. Even if you’re making all the right moves to strengthen your muscles.

Think of the body types that tend to do well in sports like Olympic lifting and powerlifting vs. bodybuilding, for example.

Powerlifters are usually huge guys, that may have a lot of size, but often don’t look “cut” or “shredded.” Many of them even have the “beer keg” body with a layer of fat or a visible gut.

But that certainly doesn’t diminish their strength when they’re putting up some absolutely massive lifts on their barbells. Many people with this body type have a lot of fat AND a lot of muscle.

For power and strength, this can be a good thing.

For aesthetics, many people prefer to have some abdominal definition if they’ve built up the strength, but it’s a matter of personal preference. If you want to cut down the fat, here are a few things to consider.

You can’t spot reduce. This is a myth. Instead, you’ll need to lower your body fat overall.

What’s the best way to lose body fat?

The Center for Disease Control and Prevention guidelines recommend at least 150 minutes of moderate-intensity exercise per week.

You should get at least 2 days of strength training, but to target body fat, you also need some sort of aerobic activity.

This includes things like:

Jogging

Jump rope

Stationary or road biking

Rowing

Elliptical

Dance

Any workout that gets your heart rate up is a good way to burn extra calories and reduce body fat. Remember, you need to be at a calorie deficit for your body to lose weight.

Cardio exercise can prompt weight loss by boosting your metabolism during a workout. Learn more about metabolism here: Are You Older than Your Body: What is Metabolic Age?

The best way to ensure a calorie deficit is to reduce the amount of food you eat.

Althoug it’s important to listen to hunger cues, geting in nutrient dense meals that fill you up, rather than the empty calories you might eat on a dirty bulk can help you shed pounds faster.

Aim to eat within the recommended amount of carbohydrates, protein, and healthy fats. Usually, the balance you should try to strike with these essential macronutrients is:

45-65% carbohydrates

20-35% fat

10-35% protein

Using these guidellines, your have a lot of wiggle room. A marathoner, an Olympic lifter and a sedentary person would all have different macronutrient balances that are more applicable,

If you want to get savvy on macros, a dietitian or nutritionist can help you create a nutrition plan that suits your lifestyle and fitness goals, keeping your grocery budget in mind.

Build lean muscle

To get abs that show through, you need to train them for hypertrophy. We usually think of ab training as quickly repping out hundreds of crunches as quick as possible.

But for most people, that’s not the best growth strategy.

Work on exercises that target all the visible parts of your abs. Splitting your abdominal training into upper abs, lower abs, side abs, and deep abs can be worthwhile in your training.

Upper Abs: Use moves like sit-ups and crunches to train the upper portion of your abs.

Lower Abs: Reverse crunches, bicycle crunches and windshield wiper workouts can be great for this area.

Side Abs: For your obliques, try side planks, oblique crunches and Russian twists. Wait, don’t Russian twists make your waist smaller? The answer’s not so obvious, and it’s something you should know if you have skinny abs.

Deep Abs: For your deep core muscles like the transverse abdominus, static holds like a plank or forearm plank can be beneficial. Dead bug exercises too are a good way to hit this area and build overall core stability.

Does building your abs make your waist bigger?

Training your skinny ab muscles to grow can make your waist bigger. After all, by targeting this muscle group, you’re directly forcing the abdominal muscles to increase in volume, which typically leads to a wider, thicker waist.

But if you’re cutting down on fat at the same time, you shrink the proportion of your torso that’s composed of fat.

This can be a little bit confusing. You may even put on weight but notice a smaller waist. Changing the ratio of fat to muscle in your ab area means your body is recomposing.

For most people, more muscle and less fat is a good thing.

It’s certainly healthier and no matter the width of your trunk, muscular abs look better than flabby ones. If you find you’re bulking up too quickly for your liking, you can always reduce the calories you’re consuming and take it slow.

To get more informed about bulking and cutting to turn your skinny abs into muscular ones, read:

What body fat percentage do I need to see abs?

Generally, women can begin to see their abs peeking through at around 14- 20 % body fat.

For men, the percentage is lower, around 10-12 %.

This varies, of course, based on your genes and training experience.

References

https://www.cdc.gov/physicalactivity/basics/adults/index.htm

Das, S. S., Saluja, S., & Vasudeva, N. (2017). Biometrics of Pyramidalis Muscle and its Clinical Importance. Journal of clinical and diagnostic research : JCDR, 11(2), AC05–AC07. https://doi.org/10.7860/JCDR/2017/24179.9276