Part III: Causes and prevention of LBP from poor posture
The purpose of this article is to discuss the causes and prevention of lower back pain that comes from poor sitting and standing posture. There are many ways LBP can develop from slouching and this article will focus on one source and attempt to provide an understanding of common motifs on how the body works. In Part II of this series, I talked a lot about the role of hip mobility restrictions in LBP and in this article I will focus on the role of the thoracic spine. Figure source
It would be helpful to read the previous parts of this series (especially Part I):
Part I: Introduction to the Anatomy and Physiology of Lower Back Pain
Part II: Causes and Prevention of Lower Back Pain in Athletes
The thoracic spine
The thoracic spine are the middle 12 vertebrae that mostly run along the rib cage. When we slouch, the thoracic spine bends forward, putting more stress on the lower back and pushing the neck and head forward. This can lead to LBP and headaches (Alexander). Figure source
Only so many bends before it breaks
The spine is a collection of versatile joints that can generate mobility and stiffness while withstanding high compression forces. Unfortunately, the stress placed on the spine means that it is vulnerable to fatigue, and later, pain. A large portion of the prevention of LBP is respecting the fatigue lifespan of the spine by reducing the number of flexions that put the spine in a vulnerable position (McGill). Patients who repeat the flexion events that aggravate their pain, such as sitting, set themselves up for worsening pain. Degeneration of the spine is completely normal, but good posture can be the difference between getting LBP now or later.
Joint by joint perspective revisited
The thoracic spine is especially relevant to the lower back because it is the joint directly above the lumbar spine. In Part II, we discussed the joint by joint perspective of training where the lower back primarily needs to provide stability while the hips and thoracic spine should provide mobility (Rusin). The hunched over position during sitting tightens the thoracic spine, which compromises our ability to maintain a good posture (Alexander).
Improving thoracic spine mobility
The press up is a valuable corrective movement that moves the user in back extension. The press up keeps the user away from flexion and counteracts the poor posture most of us assume when sitting. The bend in the spine should be distributed throughout the spine (the lower back does not articulate that much in this plane). The glutes should be relaxed. If practical, doing work while in the press up position (supported by elbows) can be helpful!
Furthermore, stretching the thoracic spine through multiple planes of motion is also beneficial. A lying spinal rotation stretch can help the thoracic spine improve its mobility. For the spinal rotation it is important to remember the emphasis is on the thoracic spine. The lumbar spine only has a rotational range of motion of 13 degrees and most people have decent lumbar mobility. The shoulder should be placed on the ground before the hips are rotated and the emphasis is on the twisting in the chest.
Misconception Correction: Some stretches are bad for LBP
A pillar of the prevention of future LBP is removing the movement that causes pain. For most people this movement is flexion. Oddly, some LBP patients stretch their spine by curling up and pulling their knees into their chest. This reduces their pain because it activates stretch receptors in the lower back muscles, but sets the patient up for worse future pain. The stretch is a flexion event that will trigger the pain mechanism they suffer from. Beware of stretches that are quick fixes to pain.
Tune in next time for a discussion on the self-care of LBP! It will be a more practical article with a healthy array of foam rolling and corrective exercises.