By Kelly Kane
Many teachers know the buzz word “core stability” and see that working the back and abs helps their clients transition out of back pain, but they may not know exactly why. Here, Kelly Kane, founder of the Kane School of Core Integration in New York City, provides a detailed look at the core muscles and how they work together to support the back and the whole body.
As humans we move in an upright relationship to gravity. We sit, stand, walk and run, often while carrying heavy loads such as our kids, bags and backpacks. When we do these activities we need to stabilize our pelvis and our low backs, and use the flexibility and strength of our hips to change levels, locomote and mobilize.
Unfortunately when the hips are tight and mobility in the hip joint is limited, movement is taken up the skeletal chain into the sacroiliac joints, sacro-lumbar junction and lumbar spine. The protocol for creating healthy backs should be to find good drop and glide of the femur bone at the hip joint, while strengthening the core stabilizers. In the Pilates venue we call this hip dissociation/differentiation and core stability.
Core Stability
The Core in Pilates refers to the muscles of the pelvic floor, the transverse abdominus, the lumbar multifidi and the diaphragm. This group of muscles encases our organs and supports our upper extremities and spine, but specific attention must be paid to strengthening these muscles.
Stability means absolutely no movement. Core stability assumes both the lumbar spine and pelvis remain immobile. In pelvic stability, the bones of the pelvis are stabilized in either a posterior or neutral pelvic position while the upper and lower extremities load the stabilizing muscles. Even the smallest rotation of the pelvis during movement means that the core stabilizers are working unevenly. Challenging the core stabilizers by loading the head, arms and legs on a stabilized pelvis will make these muscles stronger.
Lumbar stability is stability of all five vertebrae of the lumbar spine. When the vertebrae are stabilized in neutral pelvis, the small lumbar multifidi and the transversus abdominus (TVA) work in opposition to each other to stabilize each vertebra (see diagram below). When assessing lumbar stability, it is vital to assess the stability of each spinal segment. It is possible to have segmental stability in all but one of the spinal segments. The trick is strengthening the core stabilizers so that all of the spinal segments are stabilized. In a posterior pelvic orientation lying supine the low back muscles are taken out of the equation, but the lumbar vertebrae are stabilized because the abdominal muscles push the lumbar vertebrae into the ground, inhibiting their movement. In neutral pelvis the ASIS and the pubic ramus are level in the coronal/frontal plane. For most people the lumbar vertebrae will be arching anteriorly, assuming a natural lordotic curvature. For our purposes we will talk about core stability, as it relates to the Pilates repertoire, in neutral pelvis.
The Core Stabilizers
Pelvic Floor
The most important of the muscle of the pelvic floor for postural support is the levator ani (see diagram below) which is comprised of three very different units. The pubococcygeus originates at the left and right pubic tubercles and courses posteriorly, running lateral to the genitals. The two sides meet behind the anal opening and then bifurcate as it runs up the anterior surface of the coccyx. The iliococcygeus arises from the lower aspect of the two iliac fossa and inserts at the coccyx. The ischiococcygeus runs from the two ischial tuberosities to the coccyx. Pelvic floor strength is primary for low back health because it is literally the inferior anchor of the spine: all three aspects of the levator ani attach to the tailbone. These muscles form a cup or a diaphragm that has the capacity to contract in and up. The pelvic floor muscles support the inferior organs of the pelvis, such as the bladder, prostate, uterus and rectum.
Strength and balance in the pelvic floor is greatly affected by pelvic orientation (neutral, anterior or posterior). To feel this for yourself, try sitting on a chair feeling your SITS bones. Come into neutral pelvis by bringing the ASIS and the pubis in the same plane. You will probably feel as though you are a little forward on your SITS bones. Contract your pelvic floor by pulling the right pubic bone to the right tailbone, the left pubic bone toward the left tailbone, the SITS bones together, close the anal and vaginal opening or condense around the base of the penis and pull everything up. Now tuck the tailbone under and sit on the back of your SITS bones, taking a posterior orientation, and contract the pelvic floor in the same way. You will probably feel more contraction around the anal opening. Do the same thing in an anterior pelvic orientation by rocking forward on your SITS bones and contracting the pelvic floor. You will most likely feel more contraction in the anterior pelvic floor around the genitals. When you are executing your Pilates exercises with a neutral pelvic orientation you will be more likely to recruit the pelvic floor evenly front, sides and back.
Transversus Abdominus
The transversus abdominus (TVA) is the deepest abdominal muscle. It literally forms a girdle that encases our organs and supports our spine. At the pelvis, it attaches to the inguinal ligament, the iliac crest and the sacrum. It also has attachments to the lumbar spine by way of the thoraco-lumbar fascia. At the thorax it attaches to the inner surfaces of ribs seven through twelve and has fibers that interdigitate with the diaphragm. A healthy TVA is said to contract whenever we move; when we lift our arms, walk, turn our heads. When it contracts it axially elongates the spine and assists in spinal flexion and rotation. It also aids in respiration and contracts when we laugh, sneeze, cough or forcefully exhale. When the TVA contracts with the lumbar multifidi, it stabilizes each of the lumbar segments. It is the muscle that reduces the diameter of the waist and helps us “scoop.”
The TVA is extremely important to low back health. When it contracts and axially elongates, it literally decompresses the lumbar spine. As an intervertebral stabilizer, it protects the low back and the intervertebral disks by “stiffening” the spine so that it can sustain loading.
Hip Disassociation/Differentiation
The hip joint is the articulation between the femoral head and the acetebulum of the pelvic hemisphere. The femoral head is a ball and the acetebulum is a cup. The hip joint is happiest when the ball literally spins in the cup. When the hip flexes the ball scoops out the cup, as if a melon scooper were scooping out a melon. In hip flexion the scooping happens posteriorly, in abduction the scooping happens medially, in extension the scooping happens anteriorly. When there is an incapacity to scoop, mobility is reduced and the mobility will be taken up or down the skeletal chain. When executing this scooping action the pelvis half has to diassociate/differentiate from the movement of the femoral head. The capacity to stabilize the core allows the pelvis to stay in one position while the femoral head scoops or drops and glides in the socket.
The action of hip disassociation/differentiation happens when you reach your ischial tuberosities or sits bones as you descend to sit in a chair. The pelvis stabilizes and the femur heads scoop out your pelvis creating a deep crease at the front of the hip, as the photo at right demonstrates. This action is also the action that keeps the back happy when you are change levels to pick something off the floor. There should be the same action of pulling the abdominal muscles in, engaging the pelvic floor, reaching the sits bones back while mobilizing through deep flexion of the knee and hip joint to change levels. The action of deep knee and hip flexion requires sufficient strength through the quadriceps, hamstrings and gluteals. Many people don’t have adequate strength in their legs to squat 30-50 times a day to pick up the kids toys, get goodies out of the bottom of the fridge or lift a heavy bag of groceries. Correct biomechanics and a deep understanding of the core stabilizers and how to get good hip disassociation/differentiation are primary to any Pilates practice.
Kelly Kane, founder of the Kane School of Core Integration, has been teaching Pilates for more than a decade. She studied with Romana Kryzanowska, Hila Paldi and Irene Dowd, and completed the training program at the Pilates Institute in Santa Fe, two years of the BodyMind Centering teacher-training program and a certification in massage from the Florida School of Massage. Her manual therapy repertoire includes Structural Integration, CranioSacral Therapy and Visceral Manipulation, and she cultivated her manual perception skills through three years of human cadaver dissection at the New Jersey School of Medicine and Dentistry. Her expertise also includes GYROTONIC® and Continuum Movement.
Illustrations ©Elijah Leonard
