Recently, it has been suggested that sitting is the new smoking. The American Cancer Society did a study that showed women that sat for more than six hours a day had a 37% increased risk of dying compared to those that sat for three hours a day. This was the case even if they exercised. Another study by the University of South Carolina discovered that men that sat (either watching TV or driving) for 23 hours per week or more were 64% more likely to die of heart disease compared to men that sat for 11 hours per week or less. Once again, this was true even if they exercised regularly. So it seems we're not exempt from health issues if we workout in the morning and chill out on the couch for the rest of the day. The above listed studies addressed death and general inactivity; this discussion will be a little less morbid and will review the musculoskeletal impact of sitting and will highlight the mayhem created by a cranky iliopsoas.

Literature Review

How harmful can the actual act of sitting really be? A study by Kelsey showed a specific link between prolonged sitting and the incidence of herniation (Kelsey 1975). Callaghan et al. 2001, showed that the sitting posture has significantly higher low back compressive loads than standing. Nachemson (1966) documented higher loads on the discs in varying sitting positions compared to standing. This was supported by another study indicating that standing postures impose up to 10% less intradiscal pressure than sitting (Rohlmann 2001). Occupations that require prolonged sitting have been shown to have an increased risk of low back pain (LBP) within the first year of employment (Van Nieuwenhuyse et al 2004). Prolonged sitting has also been associated with swelling of the lower extremities, venous disorders and negative vascular effects (Allaert et al 2005, Kroeger et al 2004).

Now, before you condemn all chairs as vessels of torture, there is research suggesting that sitting may not be all that bad. A study by Claus and others suggested that intradiscal pressure is often similar in standing and sitting, and that sitting is unlikely to pose any threat to healthy discs. The researchers concluded that sitting is no worse than standing for LBP or disc degeneration (Claus et al 2008). Occupational studies investigating the risk of sitting vs. more strenuous occupations indicate the more sedentary jobs have less LBP than those in more physically demanding type jobs (Vingard et al 2000, Levangie 1999). These results echo a literature review done by Hartvigsen and others. Their review found less back pain among those with sedentary jobs compared to people holding jobs that require lifting, driving, standing or bending (Hartvigsen et al 2000). Another systematic review had similar findings with the researchers concluding that a sedentary lifestyle by itself is not associated with LBP (Chen et al 2009). A review by Lis and others also concluded that sitting in and of itself may not result in LBP; however, if you combine sitting with other factors such as a stressful work environment, sitting in awkward postures and sitting for more than half of the workday, the risk of LBP goes up exponentially (Lis et al 2007).

Why The Discrepancy?

Now, at this point you might have realized that the body of research regarding sitting is a bit contradictory. Some researchers concluded that sitting is worse than standing; others claim the opposite is true. Some say LBP is a result of sitting while others suggest no specific relationship exists between LBP and sitting. The truth is it is difficult to establish causal links between health outcomes and any one specific behavior. For example, those that sit all day may assume other pain provoking or spine destructive behaviors such as smoking, poor sleep habits, bad nutritional habits or maybe have poor stress coping skills. Along these same lines, it is very probable that genetic and gender factors influence how caustic prolonged sitting might be. For these reasons, it is important to note that individual differences may enable some to tolerate sitting for long periods of time with no ill effects, while others threshold for pain and/or problems might be considerably less.

Is There An Ideal?

Not surprisingly, there is a lack of consensus as to what the ideal sitting position is (if there is one). One of the more frequently cited risk factors of LBP is loss of lumbar curve (Pope et al 2002). Unfortunately, the majority of us sit in a posture where neutral lumbar lordosis is reduced, with some individuals using the lumbar spine as a seat cushion. If this posture is maintained for long periods of time, it can lead to tissue creep (lengthening of tissue when load is applied over time), ligament laxity and a loss of stability (McGill & Brown 1992). Reduced lumbar lordosis is also known to place compressive forces on the discs of the spine, which over time can lead to degenerative changes, herniations and nerve root compression. Furthermore, longstanding loads applied to discs and ligaments are subjected to micro-damage that can lead to inflammation, local muscular spasms and pain (Solomonow et al 2003). This is compounded by the fact that, as we age, gross injuries to discs never fully heal and insult to one area of the spine is believed to increase load-bearing to adjacent tissues increasing the likelihood of damage spreading (Adams & Roughley 2006).

Clearly, sitting with a flexed lumbar spine is a no-no; however, before setting up plumb lines and challenging clients to "sit tall," we must recognize that sitting with erect posture involves high levels of activity of the psoas and the back extensors, which are known to impose high compressive forces on the spine. McGill suggests there really is no ideal sitting posture; rather individuals should vary postures to reduce the risk of tissue overload (McGill 2007). Some studies have shown that distributing weight directly on the ischial tuberosities increases spinal loads and can result in paraspinal muscle spasm and hyperexcitability, and suggest a more ideal chair is one equipped with a downward tilt (20 degrees) of the sitting surface, along with lumbar support (Pope et al 2002, Makhsous et al 2009). Bottom line, some seated postures may be better than others, but no static posture bests movement.

Ground Zero For Persistent Sitters

Many muscles are caught up in the imbalance resultant from prolonged sitting. For a few reasons, I believe the iliopsoas may be most deserving of our attention. The psoas portion of this muscle has fibrous attachments to the anterior aspect of all lumbar transverse processes and to the anteromedial aspects of all lumbar discs and bodies with the exception of the L5/S1 disc, although anatomical variations are not unheard of. (Bogduk & Pearcy 1992) The iliacus portion of this muscle originates from the upper ridge of the iliac fossa and merges with the psoas sharing a distal attachment on the lesser trochanter of the femur. Given these attachments, it follows that it can impose significant compressive and shear (one vertebrae shifting forward on the other) forces on the spine. Furthermore, because of myofascial links, iliopsoas dysfunction can lead to thoraco-lumbar instability, pelvic floor and breathing issues, and a number of biomechanical problems that will extend from head to toe.

Proximity of nerves: The lumbar plexus (nerve bundle in the low back) is embedded within the psoas in most people, which means potential nerve entrapment and big trouble for anything innervated by these nerves when psoas dysfunction is present (Kirchmair et al 2008). Interestingly, because of it's proximity to the lumbar plexus and abdominal organs, Ida Rolf and many others have suggested that the health of this muscle is essential for proper functioning of the kidneys, adrenals, digestion and effective metabolism in the reproductive system.

It's cranky: Vladamir Janda found that the psoas muscle is prone to a low irritability threshold, which means the brain is going to turn it on with the slightest instigation. If sitting isn't enough provocation, combine it with a little stress, and the CNS will probably decide to keep the psoas engaged. In this case, the activity of the psoas will limit the functional capacity of the glute muscles (reciprocal inhibition) and motor patterning will be affected. This alteration leads to a cascade of compensation, where the back extensors, hamstrings and quads must do the work of the glutes (synergistic dominance). Janda characterized this widespread imbalance as lower cross syndrome (LCS). In essence, LCS describes a perpetuating cycle of muscle imbalance, motor pattern dysfunction, proprioceptive deficits and joint instability; all of which lead to a hugely stressed CNS.

Assessment And Modified Thomas Test

Outside of asking how many hours per day your client sits, how can we distinguish iliopsoas trouble? There are a number of ways, I'll list two. First is identifying the pain patterns associated with iliopsoas TrPs. TrP referral from the iliopsoas will typically produce low back pain, generally on the same side, running vertically from the SI joints along the lamina groove and spanning up to the 12th rib. Referral can also present on the anterior thigh and groin area of the same side (Travell & Simons 1993). Prolonged sitting or standing, sit-ups and running will often be painful. The client may get some relief when lying down, although sleeping in a fetal position is thought to provoke these TrPs.

Second, if you are not awesome at body reading; the modified Thomas test is a simple method of checking for a shortened iliopsoas. Be sure to test both sides. Have your client sit at the very end of the table. Instruct them to hug the opposite knee toward their chest. With your support, help them roll back onto the table into a supine position. Be certain that the client's lumbar spine is slightly flexed and the pelvis is in a posteriorly rotated position. Observe whether the thigh is elevated off of the table or abducted. Normal resting length of the iliopsoas will permit the upper leg to rest comfortably on the table with no external rotation at the hip.

Treatment (Or Not)

Although this article will present psoas and iliacus release techniques, keep in mind muscles don't act in isolation and your treatment should include other areas of restriction. The psoas is a segment of what Thomas Meyers coined the "Deep Front Line" in his book Anatomy Trains and investigation of this entire train is deserved in all chronic sitters.

Direct iliopsoas work is not without risks and many therapists choose not to perform it. Although deep abdominal work does carry some risk, if you go slowly, remain highly aware of any pulses, I believe the risk/reward benefits are in favor of doing this treatment. A few specific contraindications include pregnancy, hernias and any risk or presence of a vascular disorder. If you have not had in-classroom experience, or if upon screening and interviewing you have doubts about the health and readiness of your client to receive this work, do not do it. There is still great value in working the iliopsoas' neighbors (in particular rectus femoris and quadratus lumborum) and performing muscle energy techniques (MET) for the hip flexors (see Leon Chaitow's book Muscle Energy Techniques for a detailed description). Likewise, because of fascial links to the diaphragm and ensuing engagement of the parasympathetic nervous system, diaphragmatic breathing exercises will be hugely beneficial.

Iliopsoas Release

Let's start with the psoas belly. With the client supine, stand on the same side of the hip you are going to treat. Flex the knees and hips of both legs so their feet are flat on the table, as it is far more forgiving to begin this work with the abdominal wall in a relaxed position. Place your fingers, one hand on top of the other, directly medial to the ASIS (although the muscle is more expansive, I don't travel much above the navel). Apply gentle pressure posterior and slightly medial. To be certain you are in the right place, have your client elevate the foot (only slightly) of the treatment side; you should feel a distinct tightening of the psoas with your fingers. Once you have established that you are on the psoas, use gentle pressure and soft fingers to sink into the psoas. Follow your client's breathing pattern and be patient; slow and steady is the name of the game here. Reposition your hands if you feel a pulse or if your client feels any sharp pain. Likewise, if you feel any guarding, ease up and sink back in under your client's guarding radar.

Pin And Stretch Techniques

Moving the arm: Once you feel some release of the psoas, maintain the position of your fingers and have the client slowly move the arm into shoulder flexion (reaching overhead). Return to the starting position and repeat this 5-6 times. Sliding the heel: As you continue to work the psoas, instruct you client to keep their belly relaxed and have them slide their heel on the table until their leg is completely straight. Return to the starting position and repeat this 5-6 times. To access the trigger point that hides around the distal attachment of the iliopsoas, I usually straighten the client's legs allowing the involved hip to slightly externally rotate. Treatment involves static compression with 1-2 finger tips just beneath the inguinal ligament and lateral to the femoral pulse.

I have found that the iliacus may best be treated from a side lying position. Have the client roll onto their side so the involved hip is up. Have them slightly bend their hips and knees. With soft finger tips (one hand placed on top of the other), hook your fingers so they are gently pressing along the inner surface of the ilium, treat as much of the iliacus as possible with compression and small friction strokes. Finish with MET for the hip flexors.

Despite some contradictions within the research, most would agree that sitting does have the potential to negatively affect the form and function of the body. The bottom line is motion will always trump even the most neutral static posture, so it is essential to encourage your clients to move as much as possible throughout the day. Finally, the iliopsoas is easily antagonized and is positioned perfectly for creating all kinds of structural and functional mayhem; consider this when formulating your bodywork plans.

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