Lower lumbar spine axial rotation is reduced in end-range sagittal postures when compared to a neutral spine posture

Abstract

Rowing, fast bowling in cricket and cycling are activities that combine axial rotation with flexion and/or extension of the lumbar spine and they are known to carry greater risk of low back pain (LBP). It can be hypothesised that this increased risk is in part, related to the spine being rotated whilst at end range of spinal movement. Few studies have investigated the capacity of the lumbar spine to rotate in various sagittal postures, and these studies have generated disparate conclusions. The purpose of this study was to determine whether the range of lower lumbar (L3–S2) axial rotation decreased in end-range flexion and extension postures when compared to a neutral spine posture. Eighteen adolescent female rowers (mean age=14.9yrs) with no history of LBP were recruited for this study. Lower lumbar axial rotation was measured by an electromagnetic tracking system (3-Space Fastrak™) in end-range flexion and extension and neutral postures, in both sitting and standing. A two-way ANOVA with two within-subject variables was used to compare whether the range of axial rotation differed with posture (neutral, end-range flexion and extension) and position (sitting and standing). There was a reduction in the range of lower lumbar axial rotation in end-range extension ( p 0.001 ), and flexion ( p 0.001 ) when compared to neutral. Further, there was a significant difference evident for the range of lower lumbar axial rotation measurements in flexion when sitting was compared to standing ( p = 0.013 ). These results may demonstrate an increase in stiffness of the passive spinal structures in end-range flexion and extension, compared with maximal rotation available in neutral spine postures. It is proposed that axially rotating the lower lumbar spine whilst in end-range spinal postures may increase the risk of tissue strain due to a decrease in tissue compliance in these positions.