In Pilates, the core, or “powerhouse” as referred to by Joseph Pilates , is the origin of all movement. The muscles of the core work together to allow movement in different directions, support the spine and keep the organs in place. Therefore core strength and stability results in coordinated, controlled movement throughout the body as well as improved posture and a leaner, longer torso.
One of the best concepts for the core in Pilates is Centering. It is one of the 8 Pilates Movement principles and explains how all movement originates from the center of the body and moves outward through the extremities. This is an excellent image of not only how the core functions, but also dives into the heart of Pilates as well.
At Lee Pilates Method, we refer to core strength as integrated movement and specifically focus on the ability to maintain the alignment of the pelvis, spine and shoulders. A strong core can potentially prevent injury. Lack of core stability results in undesired and/or compensatory movement, such as excessive hip rotation while running or pronounced hyperextension of the spine while in a plank position.
In this blog post, we will be going in depth about the core muscles and why they are essential to Pilates.
What are the primary muscles of the core?

According to the Pilates Method Alliance (PMA), the core consists of four primary muscles: the diaphragm, multifidus, transverse abdominis and pelvic floor. Let’s take a look at each of these muscles in more detail.
The Diaphragm – The Breathing Muscle
The diaphragm is commonly known as the breathing muscle because it assists in expiration and inspiration (breathing out and in). Although its primary function is to help us breath, the diaphragm can help us stabilize the lower spine.
The muscle’s pressure acts like a cushion on the front of the lower spine. In Pilates, the diaphragm activates other deep core muscles responsible for stabilization. This stability creates the strength and integration needed for both refined and powerful movements.
Transverse Abdominis – The Pelvic Stabilizer
The transverse abdominis (TVA) is the deepest of the four abdominal muscles. TVA muscle fibers run horizontally. When these muscle fibers contract, they create a feeling of “cinching” or tightening around the pelvis like a girdle. The primary function of this muscle is stabilization.
The TVA is easier to activate during the exhale in the breath cycle. This is why it is often one of the primary muscles of focus in Pilates. It sits below the internal and external obliques and rectus abdominis and spans from the lower ribs down to the pelvis. Because this muscle acts as a natural girdle or corset for the trunk and pelvis, it supports the spine during movement and protects the internal organs. Activating this muscle during movement requires meticulous concentration, practice and breath control.
Multifidus – The Spine Stabilizer
The multifidus is a series of muscles attached to the spinal vertebrae. It is the deepest of the spinal extensors, or muscles that help us hold the spine upright. It runs from the sacrum to the top of the cervical spine (neck).
The functions of the multifidus are to remove pressure from the vertebral discs. This helps distribute body weight along the spine, maintain upright posture, and provide spinal stability. Prior to movement, the multifidus is activated to prevent injury. The multifidus and the TVA are widely considered two of the most important muscles for core stability. Practicing the activation of the multifidus during movement helps to map this important muscle to the brain and strengthen it.
Pelvic Floor – The Hammock
The pelvic floor muscles are located within the pelvis between the tailbone (coccyx) and the pubic bone. The Lee Pilates Method puts great focus on integrating these muscles into overall movement. The pelvic floor muscles are actually composed of two muscles. These are known as the Kegel muscles: the coccygeus and the levator ani (pubococcygeus, puborectalis, iliococcygeus). It stretches like a hammock across the base of the pelvis and provides support for the pelvic organs.
The pelvic floor is important in the maintenance of continence, assists to facilitate birth, is important for healthy sexual function and helps to maintain optimal intra-abdominal pressure. The pelvic floor muscles work with the deep abdominal and back muscles and diaphragm to stabilize and support the spine. They also help control the pressure inside the abdomen to deal with the pushing down force when you lift or strain – such as during exercise.
What other muscles in Pilates are involved in core strength?
As we have discussed, the primary function of the core in terms of Pilates and other methods is to provide stability for the spine and pelvis. This stability offers a solid foundation from which to safely receive or transfer force through the extremities (legs and arms). In my Pilates practice and more broadly, the core is not just your abdominal muscles. In addition to the internal organs and the muscles discussed above, the internal/external obliques, rectus abdominis, spinal extensors and hip flexors/extensors are all important for core strength.
Activate your core with Lee Pilates Method
Interested in learning how to properly activate your core? Check out my on-demand Pilates classes or book a private session online or in my Austin-based studio.