Our trunk is a complex system of both both passive (spine, discs, ligaments) and active (muscular) elements that allow for optimal function and activity. Of these, most people are familiar with the active systems as relates to “core” strengthening, but what exactly is the core?
The trunk or core consists of both an outer core and an inner core.
The outer core is composed of large muscle groups that perform movement and power of the trunk with activities such as lifting, pushing or transitioning through space. Posterior the outer core muscles are lumbar paraspinals, lats, and quadratus lumborum while anterior consists of the rectus abdominis and the internal/external obliques.
The inner core muscles are often the link to recurrent or long standing lower back pain as then become inhibited and weakened due to injury. These muscles are responsible for providing stability to the lower torso and spine. Our inner core consists four muscle groups: the transversus abdominis, multifidi, diaphragm and the pelvic floor.
So very simply the core functions with internal muscles that provide stability to the vertebrae and pelvis while the outer core provides movement and power. With each of their unique functions there are different training programs to treat and strengthen each group, both in isolation and function. Oftentimes we get clients that present to the clinic with long standing history of back pain and are strong, however, they are strong only in the outer core and not able to actively recruit the inner core.
Stay tuned for more strength tips in upcoming posts, but for today here’s a simple exercise to begin recruiting the “inner core”:
To contract the Transversus abdominis:
This can be done in a sitting/standing or (best initially) side lying position. Begin with the abdomen fully relaxed and without tension. Gently and slowly pull in the lower abdomen (below belly button) “up and in” towards your spine a half inch to an inch. Concentrate on the sensation of tightness around the lower abdomen. If you are having difficulty, imagine just starting to zip up a tight pair of pants and what you would do to get them buttoned! Be careful not to use the diaphragm to perform the abdominal movement (inhaling to perform).
Initially the contraction may feel like nothing, but in time the tension and strength will improve. Practice isometric contraction (contract and hold) at 30-40% intensity for 5-10 seconds and repeat for 5-20 reps. Repeat 2-3 x/day. With practice and concentration this can be done anywhere throughout the day and used with activity. Good luck!
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