From: Spine J. 2010 Apr;10(4):297-305. Epub 2010 Feb 26
Sitting is associated with loss of the lumbar lordosis, intervertebral disc compression, and height loss, possibly increasing the risk of lower back pain. With a trend toward more sitting jobs worldwide, practical strategies for preventing lumbar flattening and potentially associated low back pain are important. The purpose of this study was to determine the feasibility of using upright magnetic resonance imaging (MRI) and stadiometry to measure changes in height and configuration of the lumbar spine before and after normal sitting and a sitting unloading exercise intervention.
This is a hospital-based pilot study involving pre-post assessments in a single group. The sample comprises six asymptomatic hospital employees involved in either general patient care or research writing/data collection. The outcome measures were lumbar total midsagittal cross-sectional intervertebral disc area, vertical height, lordotic angle derived from digitized MRI examinations, and seated body height measured directly with a stadiometer. Midsagittal MRI scans were performed before sitting, after 15 minutes of relaxed sitting (“postsitting”), immediately after seated unloading exercises, and approximately 7 minutes after exercise. Subsequently, seated stadiometry assessments were performed after 10 minutes of supine recumbency, 15 minutes of relaxed sitting, and every 10 seconds after seated unloading exercises until three consecutive height measurements were identical. Digitized midsagittal images were used to derive MRI based outcome measures.
After 15 minutes of sitting, mean total intervertebral disc area, lordotic angle, and vertical height of the lumbar spine decreased 18.6 mm(2), 6.2 degrees , and 12.5 mm, respectively, whereas after seated unloading exercises, these parameters increased by 87.9 mm(2), 5.0 degrees , and 21.9 mm, respectively. Similarly, mean seated height on stadiometry decreased by 6.9 mm after 15 minutes of sitting and subsequently increased by 5.7 mm after unloading exercises.
Seated upright MRI and stadiometry, as performed in this study, appear to be feasible methods for detecting compressive and decompressive spinal changes associated with normal sitting and, alternately, seated unloading exercises. Larger studies are encouraged to determine normative values of our study measurements and to determine if morphological changes induced by seated unloading predict treatment response and/or reductions in the incidence of sitting related low back pain.
These findings confirm an earlier study on the unloading sitting exercise, J Bodyw Mov Ther. 2010 Apr;14(2):119-26. Epub 2008 Jul 31. Preliminary investigation into a seated unloading movement strategy for the lumbar spine: a pilot study.
This study was a preliminary investigation into a seated unloading movement strategy for the lumbar spine using the upper extremities. With the economic burden of low back pain estimated in the billions worldwide, and also with a trend towards more jobs related to sitting, a simple distraction exercise coined chair-care is presented. An attempt to objectify using stadiometry was used to measure standing height changes after 15 min of sitting and after the exercise. The results showed significant standing height gains post-exercise when compared to post-sitting and initial standing (2.4 and 2.7 mm, respectively). No significant standing height changes were seen after 15 min of sitting. It is therefore likely that this simple seated exercise creates standing height gains of the spine. Proposed mechanisms are discussed with an emphasis on spinal hydraulics and intervertebral disc nutrition.
