Goal of the Study?

In this study, 1, the purpose was to determine the practicality of using upright magnetic resonance imaging (MRI) and stadiometry to measure changes in height and alignment of the lumbar spine before and after normal sitting and a seated unloading exercise intervention. 

Why are they doing this study?

Back pain is a global issue that has a widespread economic impact, as it’s the most common reason for work absenteeism. With the rise in technology, more than three-quarters of people sit for their workday. While it is thought that prolonged sitting is associated with disc compression and height loss, there is little conclusive evidence on how impacts low back pain (LBP). For that reason, there is need for practical interventions that would minimize the impact of prolonged sitting on the lumbar spine. 

The authors of this study, including the CEO of Dynamic Disc Design Corp Jerome Fryer, wanted to devise a study that would contribute to our understanding of the potential benefit of a practical, short-duration exercise routine on the sitting lumbar spine.

 What was done?

This was a two-part pilot study based in a hospital setting, using pre and post-assessments of one group of six participants. 

In part 1, the researchers used an upright lumbar MRI to determine changes in seated spinal configuration before and after 15 minutes of normal sitting, as well as before and after a demonstrated seated exercise intervention. For this, midsagittal MRI scans were done in the natural seating position, after 15 minutes of relaxed sitting and then right after the seated unloading exercises. This continued every 45 seconds for about 7 minutes post-exercise. 

In part 2, they used stadiometry to assess overall spinal height before and after the same conditions. First, the participants had to lie flat for 10 minutes before sitting in a standard office waiting room chair. From this, the participants’ initial seated height was measured and then again after 15 minutes of relaxed sitting and then again, every 10 seconds after the exercise routine was performed. This was done until three consecutive heigh measurements were recorded. 

Using the MRI images of four participants in Part 1 and six in Part 2, outcome measures were identified, including lumbar total midsagittal cross-sectional IVD area, vertical height and lordotic angle. They used t-tests to compare measurements and the Bonferroni method was used to eliminate comparison bias

What did Jerome Fryer and his team find?

Overall, the researchers found that measurement values were generally lower immediately after sitting and higher immediately after exercise. This was most evident with the lordotic and lumbar height measurements. The mean lordotic angel and vertical height of the lumbar spine decreased 6.2° and 12.5 mm after sitting and then increased 5° and 21.9mm postexercise, respectively. With the mean total IVD area, they found a decrease of 18.6mm and postexercise increase of 87.9mm2.

Stadiometric assessments showed that seated height decreased by 6.9mm after 15 minutes of sitting and increased by 5.7 mm after exercises.

The researchers found both MRI and stadiometry was able to detect changes in the spine after sitting and exercise. While the small sample size means the findings are not generalizable to the broader population, the anecdotal findings show that seated unloading exercise can have an immediate effect on sitting-related LBP. Furthermore, the loss of height after sitting was demonstrated and supports other studies with similar findings. 


There are a number of limitations outlined by the researchers. These include small sample size, lack of precise determination of midsagittal alignment and no control of subjects’ activity level before the MRI assessment.

Why do these findings matter?

The use of MRI and stadiometry seem to be good methods for detecting spinal changes associated with sitting. Moreover, given the number of seated workers, having a simple and potentially preventative exercise intervention to limit the negative outcomes of prolonged seated would be a great benefit.