Why Transversus Abdominis and Multifidus Matter More Than Most People Think in the Kinetic Chain

Dear reader,

Every day in clinic I meet people with lower back pain, pelvic discomfort, hip tightness, knee irritation, or even neck tension, and very often after a proper assessment we arrive at a similar conclusion. The chain is struggling because the core is not doing its job well enough.

The interesting part is that many people still think core simply means abs. In the modern fitness world, the word core has been reduced to visible stomach muscles, planks, and heroic facial expressions on gym mats. But in real body mechanics, the core is much more than that.

The core is the central stabilising system of the body. It helps organise the relationship between the ribcage, spine, pelvis, and hips. It creates support, manages pressure, and allows force to travel through the body in a more efficient way. When this central support is weak, delayed, or poorly coordinated, the rest of the body begins to compensate.

That is when the lumbar spine starts working too hard. The pelvis may become less stable. The hips may grip instead of moving freely. The knees may take more load than they should. Even the neck and shoulders may tighten because the trunk is no longer providing a reliable base.

So what is the core actually made of

At the deeper level, the core includes transversus abdominis, multifidus, diaphragm, and pelvic floor.

Transversus abdominis is the deepest abdominal muscle. It wraps around the trunk like a natural corset. Its job is not to look impressive on a beach. Its real job is to help create internal support and improve trunk stability during movement.

Multifidus is a group of small deep spinal muscles that help stabilise each segment of the spine. These muscles are extremely important for fine spinal control. When they are weak or inhibited, the body often relies too much on larger superficial muscles, which creates stiffness but not always true stability.

The diaphragm is also part of the core. Most people know it as a breathing muscle, but it is also a major pressure regulator in the trunk. Good diaphragm function helps support the spine and coordinate with the abdominal wall and pelvic floor. Poor breathing mechanics often go together with poor core control and extra tension in the neck and ribcage.

The pelvic floor forms the lower part of this support system. It works together with the diaphragm and deep abdominals to create stability from below. When this coordination is poor, the pelvis often feels less supported and movement becomes less efficient.

There are also the more visible and more familiar muscles such as the internal obliques, external obliques, and rectus abdominis. These muscles help with rotation, bending, trunk control, and force transfer between the upper and lower body. They matter, of course, but they work best when the deeper core system is doing its share.

Then there are muscles that often become overworked when the core is weak.

Quadratus lumborum is one of them. It is not a villain. It is simply a muscle that frequently works overtime when the trunk lacks deeper support. Psoas can also become overactive in people who sit a lot, brace a lot, or try to stabilise through tension rather than coordination.

Why core weakness affects the whole kinetic chain

The body works as a linked system. It is not a collection of isolated parts. If the centre lacks control, the outer parts must compensate.

When the trunk and pelvis are not well supported, the hip muscles often change how they work. Some become overactive, some underactive, and load transfer through the pelvis becomes less efficient. That can influence how the femur moves, how the knee tracks, and how the foot receives force during walking, stairs, or exercise.

At the same time, poor trunk support can affect the ribcage and shoulder girdle. If the ribcage is stiff or poorly positioned, shoulder blade mechanics often change. Then the neck joins the drama, usually without being invited.

This is why a weak core does not only create back pain. It can contribute to problems above and below. In many cases, the painful area is only the place that is complaining the loudest, not necessarily the place where the real problem began.

The real meaning of good core strength

In JANMI thinking, good core strength is not just about being strong. It is about timing, support, coordination, pressure control, and load sharing.

A healthy core should not be permanently tense. It should respond when needed and relax when appropriate. That is very different from living in a constant brace. The body does not want a rigid centre all day. It wants an intelligent one.

This is why some people with impressive gym strength still have pain. They may have strong outer muscles but poor deep support. And this is why some people who do not look especially athletic can still move beautifully when their core system is working well.

Core strength is not vanity. It is functional intelligence in the middle of the body.

So yes, the core matters greatly. It matters for lumbar support, pelvic control, hip function, knee loading, ribcage mechanics, and even neck comfort. It is not the answer to every problem, but very often it is one of the most important missing foundations in the kinetic chain.

When the centre works better, the whole body usually starts to negotiate more peacefully. And that is always good news for muscles that have been doing somebody else’s job for too long.

Disclaimer

This article is for educational purposes only and does not replace medical diagnosis treatment or individual assessment by a qualified healthcare professional.

Until next time,

Paulius