While postural assessments are part of the everyday experience of the working chiropractor, posture is central to functional movement and much more. As the population adapts to changing worlds of work and technology, we have witnessed a significant increase in postural concerns such as forward head posture or cervical kyphosis. Another postural concern is flat back syndrome, and it is this that a recent study took aim at.

When we think of an idea spine, we think of a spine with several gentle front to back curves. It’s almost like a lazily drawn “S”. It’s not just about aesthetics either these curves work together “to keep the body’s centre of gravity aligned over the hips and pelvis. If the lumbar lordosis [the lumbar curve] is lost, the center of gravity can be put too far forward. This is the case with flat back syndrome [1].”

But it’s not just about the centre of gravity. The spines curves also helps the body absorb shock, deal with gravity, and maintain optimal energy output. Thus, flatback syndrome can cause difficulty with several things, from simply standing upright, to undertaking the tasks of daily life. As the body moves into compensatory posture, with other spinal curves moving into altered posture to keep the body upright, we see muscles and even hips and knees taking on an increased physical burden.

It’s no surprise then, that chronic pain is often one of the results. The causes of flatback syndrome are many and varied – from degenerative diseases to fractures and surgery, or simply repetitive slumping and consistent poor posture.

Restoring the natural curves of the spine is important under the hands of caring, skilled and qualified professionals (like your local chiropractor).  But with any good treatment plan, it starts with good measurements. This is where this new study comes in.

The study took place at a university in South Korea, taking in 80 asymptomatic volunteers who reported to have had no issues for the previous 12 months [2]. It aimed to compare angles from different sections of the spine and see who they changed in relation to each-other in individuals with normal to reduced lumbar lordosis.

How they did it:

Researchers used three measurement systems to measure the global lumbar lordosis (in which the overall curve of the lower spine was measured) and regional lumbar lordosis (in which individual segments were assessed.) The participants had recordings taken while they stood comfortably for five seconds, and then they were divided into three groups, depending on their global lumbar lordosis (GLL) angle. The groups were: less than 20, between 20-30 and between 30-40 degrees.

People who had less than a 20-degree GLL were considered to represent people with flat lumbar posture for the purpose of the study. At this point, researchers took recordings from three sections of the spine, from the bottom of the thoracic to the lumbar spine. The purpose of theses recordings were to see if and how tension and pressure changes in other areas of the spine when lumbar lordosis is reduced. Essentially, this was measuring the impact of compensatory actions taken to balance the body in the absence of an ideal lumbar curve.

The Findings:

It is unsurprising to discover that as the global lumbar lordosis angle increased, the regional angle also increased. The sacrum, being the area right at the bottom of the spine, decreased (tilted forward). The researchers found that sacrum angle was therefore the best predictor of the global lumbar lordosis.

Researchers also found that:

  • GLL seems to be more affected by lower lumbar angle than upper lumbar angle. As GLL increased, RLL increased significantly, with the lower lumbar angle being higher than the upper lumbar angle.
  • The L5 segment of the spine accounts for about 40% of the GLL, whereas L1 segment accounts for only 5%.
  • The degree of lumbar lordosis decreases when the sacral tilt to the back increases in the standing position, and vice versa.
  • The anatomical association between the lumbar spine and the pelvis causes lumbar extension when the pelvis tilts forward, and lumbar flexion when the pelvis tilts backward
  • The more the sacrum tilts toward the back, the ‘flatter’ the lumbar spine becomes (reduced angle).

The researchers remarked: “We suggest that the S2  [spinal segment] value is the best single indicator of GLL in skin surface measurements” and further that there was a “reciprocal association between sacrum orientation and lumbar lordosis characteristics.

Interestingly, this was an asymptomatic population, which means findings could be different and potentially more severe in a symptomatic population. As with any study, there were limitations or opportunities for further study in order to aid understanding. For example, this study didn’t look at older individuals specifically (and age is a factor when it comes to back shape. Likewise, measurements would likely be different if the participants were sitting instead of standing.

They did not consider hip movement or muscle condition either, and this (along with sitting vs. standing articulations) would be interesting to see in future research.  So, too would the affect on leg alignment and weight bearing.

While these limitations show that the hard work of research is certainly never done, it also does give us a good hint on where to start measuring when it comes to flat back syndrome.


  1. Angevine P, Mandigo C, and Reid C, “Flatback Syndrome,” Columbia Spine, https://www.columbiaspine.org/condition/flatback-syndrome/ retrieved 22 April 2020
  2. Shin S, Yoo W (2020), “Intertial Measurement Unit-based Evaluation of Global and Regional Lumbar Spine and Pelvis Alignment in Standing Individuals With a Flat Lumbar Posture,” JMPT, Volume 42, Number 8, pp. 594-601



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