When we work to achieve a ‘6-pack’, especially if we work out regularly, the muscles we think about include the rectus abdominus, transverse abdominus, and external abdominal obliques. While it’s not wrong to strengthen these superficial or ‘vanity’ muscles, the real core goes much deeper.
Your true core involves a very specialized muscle called the “psoas” which lies deep against the posterior abdominal wall. Made up of the psoas minor and psoas major, it eventually connects to the iliacus, forming the iliopsoas muscle. The psoas functions like hip flexor and plays a vital role in the stabilization and strength of the lower spine, as it attaches the spine to the leg.
The psoas’s length has a direct correlation to low back pain and stability.
When tight, the psoas pulls the spine forward and down, leading to lordosis, or ‘sway back’, often causing low back pain. When too long or loose, the psoas is unable to provide adequate stability because the pelvis is pushed forward and the hamstrings become tight. This too can be a source of pain. The psoas has a very innate and primal response from your sympathetic nervous system which we sometimes call the “flight or fight” response. Basically this term means that when it is stressed, the psoas may contract, maintaining a state of inflexibility and tightness. When coupled with long hours in a seated position, you may experience low back pain.
Yoga is one way to combat the tightening of the psoas and keep your true core healthy. There are many poses that can help to improve the length or amount of tension in the psoas. Here are a few:
To engage and strengthen the psoas:
Supta Padangusthasana (reclining big toe pose)
Utthita Hasta Padangusthasana (standing big toe pose)
Navasana (boat pose)
To stretch/release the psoas:
Virabhadrasana I (warrior I)
Ustrasana (camel pose)
Setu Bandha Sarvangasana (bridge pose)
Stacy Rumfelt, OTR/L, OTD, CHT, CLT, CYT is an Occupational Therapist certified in the treatment of hand and upper extremity rehabilitation with OrthoCarolina. She obtained her yoga instructor certification in 2001 from Lighten Up Yoga in Asheville, NC. She practices Hatha Yoga with an Iyengar base.