Published February 2021
AUTHOR, ROB ORR
Hello my name is Rob Orr I am a Clinical Myotherapist and a Credentialed McKenzie Therapist specialising in Mechanical Diagnosis and Therapy (MDT), and also the treatment of these conditions which includes hands on therapy and corrective exercises/stretches.
I have been a Clinical Myotherapist for 19 years, and a Credentialed MDT therapist for four years. I also have a sports science background and a postgraduate background in musculoskeltal pain management.
The topic I would like to talk about today is “posture versus non ideal posture when in a seated position”. My question to you is does it matter? Some people say yes and some people say no. I say yes it does matter, maybe not for everyone but the majority in my experience. Approximately 70% of the clients that I see in my clinic that present with lower back pain with/without radicular pain, neck pain with/without radicular pain display a rapid and significant difference for the better when changing their posture while in a seated position.
Over the past four years regardless of the clients complaint whether its spinal or non spinal based, I always change the load to their lower spine from a kyphotic siting posture (sitting in a slumped position) to a lordotic sitting posture (sitting upright) while I’m conducting the subjective examination during the initial consultation. I use an ergonomic aid in the form of a lumbar roll, or a rolled up towel in the shape of a sausage with a rubber band placed at each end so to maintain this shape, and believe it or not within one to three minutes 70% (approximately) of these clients pain/discomfort improves significantly, and at times within seconds! Also on occasions the clients pain/discomfort is completely abolished while maintaining this position. So you cant tell me that posture doesn't matter when sitting! Especially if you sit or long periods of time.
If your wandering why I do this with every client regardless of their signs and symptoms it is because 43.5% of extremity pain has shown to have a spinal source whether its primary or secondary (Rosedale et al 2020). This study exploring the prevalence of extremity pain of spinal source was conducted in 2017 and the results were published in the Journal of Manipulative Therapy in 2020.
Even though there has not been any specific scientific research on this exact topic there is certainly plenty of literature out there on ideal spinal biomechanics versus non ideal spinal biomechanics, regarding the load on the hard and soft musculoskeletal structures when sitting slouched (kyhphotic posture) versus sitting in an erect (lordotic posture) concerning lower back pain with or without radicular pain.
There is also electromyographic studies out there looking at the firing patterns of the trunk muscles when sitting in a slouched position versus sitting in an erect position. These results indicate that co-contraction of the trunk muscles during sitting with ideal posture could bring about the correct lumbar curvature, effectively stabilise the lumbopelvic region and decrease focal stress on passive structures.
Dr Andrea Bernini has shown that the thoracolumbar fascia is a sensory organ in the form of a 3D fascial webbing that is highly sensitive to chemical stimulation and is rich in nerve innervation consisting of mechanoreceptors and nociceptors. Now remember that there are a lot of soft tissue structures that join to the thoracolumbar fascia at different depths, so poor posture when seated could certainly alter the length tension relationship of this tissue that could also lead to pain. Bernini also believes that the thoracolumbar fascia is more responsible for lower back pain over muscle due to its rich innervation.
Also there is epidemiological data that link disc herniation with sedentary occupations and sitting posture (Videman, Nurminen, and Troup, 1990).
Further studies conducted by Professor Stuart McGill found that repeated lumbar flexion with simultaneous compression was the easiest way to herniate the disc. What was interesting it was the repeated lumbar flexion motion that was more damaging to the disc over the compression loads. So even though in a seated position you are not doing repeated lumbar flexion but you are placing your lower spine in sustained flexion (kyphotic posture) and at the same time sustained compression. Sustained lumbar flexion and repeated lumbar flexion can cause the nucleus pulposes (the substance inside the disc) to migrate posterior and posterior laterally leading to a disc bulge that can most definitely result in lower back pain and radicular pain. Kulish et al published a paper in 1991 on tissue origin of lower back pain and sciatica and their results clearly indicated that the disc was the most common source of lower back pain and sciatica out of 17 different tissue types tested.
In summary due to the evidence presented and in my clinical experience on this chosen topic “does ideal posture versus non ideal posture matter when in a seated position” I strongly believe it does.
Thank you
Rob Orr
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