Article

OBJECTIVE: To determine what if any changes occur to the lumbar disks in the
spine after prolonged sitting with and without intermittent breaks during a
4-hour period. DESIGN: A prospective observational study. SETTING: An academic
outpatient clinic. METHODS:
The measurement of lumbar disk changes was performed
with 12 subjects after an analysis of a mid sagittal lumbar magnetic resonance
image, which measured lumbar disk height and disk diameter. Scanning and analysis
were done over a 2-day period: day 1 at the start of the work day and 4 hours
later after continuous sitting; at the start of work day 2 and after four hours
after a change in position and stretching protocol every 15 minutes. RESULTS: For
this study, we first evaluated each level of the lumbar spine for any changes
after prolonged sitting for 4 hours over the 2 days. Multiple comparisons bias
was eliminated by a Bonferroni correction to limit the overall experiment-wise
error rate to .05. The comparison was conducted by using a paired t-test when the
normality condition was satisfied and by using a Wilcoxon signed rank test when
normality was not satisfied. To test for normality, a Shapiro-Wilk test was used.
We found that, for disk height, L4-5 was significantly decreased at the end of
the sitting for day 1 but not for day 2. There were no significant height changes
for the other lumbar disks. In addition, for disk diameter,
there were no
significant differences present for any of the disks. CONCLUSIONS: Analysis of
the data shows that the greatest change in disk height is at the
L4-5 level after
prolonged sitting without intermittent breaks. The other levels did not show a
significant change in their height. The findings also showed that the L4-5 height
changes were not significant with brief positional changes every 15 minutes.
Fewer changes in disk height may correlate with an improvement in low back pain
and disability.
CI - Copyright (c) 2014 American Academy of Physical Medicine and Rehabilitation.
Published by Elsevier Inc. All rights reserved.

Langue : ANGLAIS