Lumbar spine reposition sense: the effect of a 'slouched' posture

Proprioceptive control is considered important for spinal stability and prevention of injury. However there is evidence that proprioceptive structures, that are reflexive and viscoelastic, are challenged by commonly adopted 'slouched' postures. The aim of this study was to investigate the effect of such postures on proprioceptive control. The reliability of a flexible electrogoniometer was established (ICC=0.89). Using a repeated measures design (n=32, 80% power detecting 0.5 degrees difference at 95% significance) subjects repositioned their lumbar spine immediately (3 s) and following 300 s in a 'slouched' posture, with a 15-min interval in between. Results showed a significantly reduced lumbar spine reposition sense following 300 s in a 'slouched' posture as compared with 3 s in a 'slouched' posture (P<0.001), mean difference 3.92 degrees (SD 4.35). Based on this sample, there was evidence that a 'slouched' posture, of 5 min duration, would increase reposition error by more than 2.35 degrees and less than 5.48 degrees (n=32, CI 95%). These findings support the practice of postural education to reduce potential to proprioceptive loss and injury. The electrogoniometer shows potential for use in clinical practice.