Five Mistakes People Make When Trying to Build Core Strength

If I asked you whether you wanted a stronger core, I imagine the answer would be an immediate yes.

A strong core is something most people aspire to, whether they articulate it in those words or not. We associate core strength with good posture, freedom of movement, reduced back pain, and feeling capable in our bodies. And rightly so. Your core plays a central role in almost everything you do—bending down, twisting, lifting, walking, carrying shopping, getting up off the floor, or simply standing upright with ease.

Yet despite how important the core is, it is also one of the most misunderstood areas of the body.

In my work as a soft tissue therapist and movement coach, I see the same patterns again and again. People are trying hard. They are motivated. They are doing “core workouts.” And yet they are still dealing with back pain, poor posture, abdominal weakness, or a feeling that their body just isn’t working with them.

Very often, it is not because they are doing nothing—but because they are making a few key mistakes.

In this article, I want to walk you through the five most common mistakes people make when trying to build core strength, and more importantly, how to approach core training in a way that actually supports your body for the long term.

Mistake #1: Thinking the Core Is Just Your Abs

The first and most common mistake is assuming that core strength is the same thing as abdominal strength—and more specifically, that it means strong “six-pack” muscles.

If you ask most people what exercises they would choose to strengthen their core, the answers are usually crunches, sit-ups, or perhaps leg raises. While these exercises can have their place, they primarily focus on one muscle: the rectus abdominis, the superficial abdominal muscle that runs vertically down the front of the body.

But the core is far more than that.

In reality, the core is a complex system of muscles that work together to stabilise the spine and pelvis and manage pressure within the body. This system includes:

• The rectus abdominis

• The internal and external obliques

• The transverse abdominis (a deep stabilising muscle)

• The spinal extensor muscles, particularly the erector spinae

• The latissimus dorsi, which links the arms to the torso

• The diaphragm at the top of the abdominal cavity

• The pelvic floor at the bottom

  
  

You could also make a case for including muscles such as the psoas, quadratus lumborum, and lateral hip muscles, all of which play stabilising roles. For the sake of clarity in teaching, I tend to focus primarily on the torso muscles and address the hips separately, but it is important to understand that the body does not work in neat, isolated compartments.

The key takeaway here is this: if your “core workout” only involves crunching forward, you are missing a large part of the picture.

A truly effective approach to core strength needs to include extension, rotation, breathing, and stability through both the front and back of the body.

This is why exercises like planks can be so effective when performed well. A plank, in its various forms—front, side, and back—can engage a wide range of core muscles simultaneously. That said, planks are only helpful if you have the baseline strength and alignment to perform them correctly. If not, there are many smaller, more subtle exercises that work with breath and deep stabilisers to build a foundation first.

Mistake #2: Ignoring Alignment and Movement Quality

The second major mistake is overlooking alignment.

It is very easy to roll out an exercise mat, follow a workout video, and move through the motions without really understanding what your body is doing. Unfortunately, effort alone does not guarantee results. If your alignment is off, the muscles you are trying to strengthen may not be doing the work you think they are.

One of the most important relationships to understand in core training is the relationship between the rib cage and the pelvis. Many of the core muscles attach to both structures. If the rib cage is flared upwards and the pelvis is tipped forwards or backwards, those muscles are placed at a mechanical disadvantage.

In simple terms, they cannot generate strength efficiently.

This is why I often begin core training not with traditional “core exercises” at all, but with learning how to move the legs independently of the pelvis, and the arms independently of the rib cage. Hip mobility and shoulder mobility play a significant role in core function, yet they are frequently overlooked.

When movement quality improves, strength follows naturally. Without that foundation, people often compensate—overusing certain muscles while others remain underactive. Over time, this can contribute to pain or dysfunction rather than resilience.

Having guidance matters here. A trained eye can often spot small alignment issues that are very difficult to feel on your own. Sometimes a minor adjustment makes the difference between an exercise being ineffective and it being transformative.

Mistake #3: Working Beyond Your Current Ability

The third mistake is trying to do too much, too soon—or continuing beyond the point where good form can be maintained.

This can show up in two main ways. The first is attempting exercises that your body is not ready for yet. The second is pushing through fatigue to hit a certain number of repetitions or hold a position for longer, even when alignment has started to break down.

A common example is the plank. When someone lacks the strength to hold the position, the pelvis often drops, the lower back arches, and the abdominal wall loses its supportive function.

In exercises involving leg lifts or sit-ups, another red flag is doming or coning of the abdomen, where the abdominal wall bulges forward.

This is something to pay close attention to.

Ideally, when training the core, we want the abdominal muscles to lengthen and lift, not push outward. Doming is a sign that the load is too great—either because the exercise is too advanced or because fatigue has set in.

This is especially important for anyone who has experienced pregnancy, diastasis recti, or a hiatus hernia, but it applies to everyone. Strength is not built by forcing the body past its capacity; it is built by meeting the body where it is and progressing gradually.

Quality matters far more than quantity. Fewer repetitions performed well will always be more beneficial than more repetitions performed poorly.

Mistake #4: Never Letting the Muscles Relax

This is often the most surprising one: working too hard.

In our culture, we tend to equate tightness with strength. If a muscle feels firm or tense, we assume it must be strong. In reality, muscles that are constantly contracted can become overactive and weak.

There is a point at which tension stops being helpful.

A clear example of this can be seen in people with diastasis recti. While the condition is associated with weakness of the abdominal wall, it is very common for the rectus abdominis to be excessively tight. High intra-abdominal pressure—whether from pregnancy, heavy lifting, or habitual bracing—can contribute to this pattern.

In these cases, strengthening exercises alone are not enough. Reducing tension through techniques such as massage, breathwork, and intentional relaxation is just as important.

This applies more broadly as well. Practices like Pilates or ballet involve sustained abdominal engagement, which can be very beneficial—but only if they are balanced with periods of release. Learning how to let go of the abdominal muscles is a skill in itself, and one that many people lack.

In my classes, I often finish core work with an abdominal release exercise. This is not an afterthought; it is a crucial part of building functional strength. Strength is not just about contraction. It is about the ability to contract and relax when appropriate.

Mistake #5: Relying Only on Workouts

The final mistake is assuming that core strength is built only during exercise sessions.

Even if you are very consistent, you are unlikely to be exercising for more than an hour a day. That leaves many waking hours where your body is either reinforcing good habits—or undoing your hard work.

Core strength is influenced profoundly by how you sit, stand, and move throughout the day.

One of the simplest yet most effective strategies is to improve your alignment during everyday activities. When standing, imagine lining your body up with a plumb line: shoulders over hips, hips over knees, knees over ankles. Many people tend to shift their weight forward into the mid-foot rather than back over the heels. Bringing the pelvis back over the heels and allowing the rib cage to soften can significantly improve core engagement without having to exercise.

A simple test is whether you can gently wiggle your toes while standing. If you can, your weight is likely well placed.

When sitting, the same principles apply. Aim for a neutral pelvis and relaxed rib cage. Sit actively rather than collapsing into the back of the chair, allowing your muscles to support you. Slightly tipping the pelvis forward so that you are sitting more on the top of the legs rather than directly on the sit bones can help maintain an upright, supported posture.

These small changes add up. Over time, they can make a meaningful difference to how your core functions—without adding a single extra exercise to your routine.

Building Core Strength Well

If I were to summarise an effective approach to core strength, it would look like this:

• Understand that the core is more than just the abs

• Train the torso as a whole, including the back, rotation, and extension

• Pay close attention to alignment, especially rib cage and pelvis position

• Choose exercises that match your current ability and prioritise quality

• Avoid doming or bulging of the abdominal wall

• Balance strengthening with relaxation

• Use everyday posture and movement to reinforce core support

  
  

Core strength is not about chasing a particular aesthetic or enduring discomfort for its own sake. It is about creating a body that feels supported, capable, and resilient in daily life.

When we approach the core with mindfulness rather than force, and with respect for how the whole body works together, strength becomes something that grows naturally—often in ways that surprise us.

And that, ultimately, is what being aligned and active is all about.