Lengthening the spine

Lengthening

Image one

and safeguarding the spine

in forward bending.

Roll Up, Neck Pull and others‌. Š Anthony Lett 2015. All rights reserved.

In this discussion we cover the trunk, in particular the thoraco-lumbar complex (TLC) the thoraco-lumbar fascia (TLF), and how understanding the workings of this region can be used to enhance the benefits of forward bending and decrease the risk of lower back strains.

The thoraco-lumbar complex (TLC) has been studied extensively. For those interested in further reading a landmark work was from Hodges in a book titled Therapeutic Exercise for Lumbo-pelvic Stabilization: A Motor Control Approach for the Treatment and Prevention of Low Back Pain.

The TLC is a multilayered structure comprised of the thoracolumbar fascia and the muscles that connect to it. This composition of passive fascial tissues and active muscular structures acts as a corset-like structure that encircles the torso. (See image one) Research suggests it plays a key role in maintaining the integrity and stability of the lumbar spine and the sacroiliac joint and is also important for load transfer from the upper limbs to the lower limbs. Engaging the muscles that connect to the thoracolumbar fascia acts to stabilize the spine and trunk.

transversus abdominus

Note the corset type structure of the transverses abdominus, the deepest core muscle of the trunk.

To illustrate its function, imagine a water balloon.(Image two) Squeezing the middle and decreasing the circumference of the tube results in an increase of its' length (to maintain the total volume). The torso, with the abdominal cavity, can be viewed in the same manner: tensioning or squeezing the abdominals, in particular the transversus and internal obliques, acts in combination with the TLF to lengthen the torso and lift and stabilize the lumbar spine.

Image two

INTRA-ABDOMINAL PRESSURE This lengthening of the torso takes place through several mechanisms that work together to different degrees depending on the position of the trunk. The first action relates to intra-abdominal pressure (IAP). Engaging the abdominal muscles mentioned above, the pelvic floor and the muscles of the larynx, which close the glottis, increases IAP, which numerous scientific studies have indicated stabilizes the lumbar spine. The circumferential arrangement of the transversus abdominus muscle in particular compresses the fluid content of the abdominal cavity which leads to a rise in pressure. The theory is that this muscle contraction acts upwards on the diaphragm like a balloon, (see image two) lifts and supports the thorax, thereby supplementing the back muscles and providing a trunk extensor moment. The mechanism is said to have a larger moment arm than the trunk extensor muscles and hence some of the compressive stress on the lumbar intervertebral disks would be relieved by ten to 20 %. (See Hodges et al)

that as they lengthen into a stretch, they can exert a passive pull on the fascia. These various mechanisms contribute to lengthening the torso and stabilizing the lumbar spine. (I have provided a number of scientific references on this subject below.)

HOW TO STRETCH Try the simple posterior stretch pictured (image 3) to explore lengthening the trunk and stabilizing the spine. The cue for activating the abdominal core is to draw the navel towards the lumbar spine in an attempt to narrow the entire waistline. Studies conducted by Professor McGill (Low Back Disorders) and others have revealed that very modest levels of co-contraction of the core muscles are all we need to protect the spine. Fixing the hands on the foot bar and pulling on it lightly engages the latissimus dorsi. This will exert a passive pull on the fascia and contribute stabilizing the lumbar spine also.

Image Three The lats

HYDRAULIC AMPLIFIER The second mechanism relates to tensioning the TLF. Activating the transversus abdominis muscle tensions the TLF, thereby providing resistance to flexion at the lumbar spine.

Furthermore, the transversus abdominis muscle has attachments to the thorax; engaging it transfers stresses from the lumbar region to the thorax and shoulders. Tensioning the TLF also improves the efficiency of the back muscles (surrounded by this fascia) through a mechanism known as the hydraulic amplifier.

Because the erector spinae are surrounded by the TLF, its various layers resist muscle expansion during contraction. This tends to straighten the spine (think of how a section of bicycle tire straightens when you fill it with air). Finally, the erector spinae muscles have fibers that insert onto the interior surface of the TLF so

transversus abdominus

You can incorporate these same principles into the Elephant exercise too-image 4. Engage the thoracolumbar complex by co-activating the deep abdominals and the erector spinae (and quadratus lumborum) to lengthen the trunk and to lift the tailbone, respectively. The cue for the erector spinae is simple -point the bottom bones toward the ceiling and lift the sternum/chest. The erector spine cue will also

Š Anthony Lett 2015. All rights reserved.

increase the hamstring and calf stretch by pulling the pelvis into anterior tilt. Image five illustrates this anterior tilt effect of the erector spinae.

Image four

Erector spinae

that prevents movement re-education. To move with “spontaneous zest and pleasure” as Joe Pilates intended requires this kind of careful work performed with “concentration, control, precision, focus and breathing” as he emphasized.

Give it a go!

REFERENCES Hodges PW, Eriksson AE, Shirley D, Gandevia SC. “Intra-abdominal pressure increases stiffness of the lumbar spine.” Journal of Biomechanics. Sep 2005; 38(9):1873-80.

Bjerkefors A, Ekblom MM, Josefsson K, Thorstensson A. “Deep and superficial abdominal muscle activation during trunk stabilization exercises with and without instruction to hollow.” Manual Therapy. Oct 2010; 15(5):502-7. Epub 2010 Jun 8.

Encouraging the protective and stabilizing mechanisms of the thoraco-lumbar complex in Pilates, even in forward bends, can be protective, particular of the intervertebral discs. Forward bends are often discouraged, often with graphic descriptions of lumbar disc herniation’s. This can be misguided, and disempowering to the client. Research is demonstrating that it is far better to explore with care and awareness the practices above than to encourage a ‘sick role’

NOTE TO READERS! Since writing this article several years ago, I have come across several excellent images of the TLC which Im going to insert below. Enjoy :) reference: Kapandji, The physiology of the Joints Vol 3. © Anthony Lett 2015. All rights reserved.