The effect of two lumbar belt designs on trunk repositioning sense in people with and without low back pain.

Objectives: Low back pain (LBP) has previously been associated with impaired lumbar proprioception, which may lead to and/or perpetuate joint instability as a cause of LBP. Wearing a lumbar belt (LB) may be beneficial in this regard. The primary aim was to determine the effect of 2 LB designs (extensible and non-extensible) on trunk repositioning sense in people with and without LBP. A secondary aim was to evaluate whether patients showing different clinical signs of lumbar instability differentially benefit from LBs in terms of lumbar proprioception.

Design: Within-group experimental study with a healthy control group.

Methods: In total, 38 patients with LBP and 19 healthy controls participated in this study. Lumbar proprioception (position sense) was measured with participants sitting in a device that allowed for generating movements in axial rotation. Three experimental conditions were compared: (1) no LB, (2) extensible LB, (3) non-extensible LB. Four repositioning errors were computed for each experimental condition: constant error (CE), absolute error (AE), variable error (VE) and total variability (E).

Results: CE and AE scores were higher for LBP patients than healthy controls (all P<0.001), but scores did not significantly differ by condition. Additional subgroup analyses of clinical signs of instability were inconclusive, showing the same results in LBP patients with low and high instability scores (all P<0.001).

Conclusions: This study confirms a significant loss of proprioception in trunk axial rotation in patients with LBP. Wearing an LB did not improve proprioception, but the contact between the LB and the skin might depend on the movement direction. Future studies should investigate the 3 planes of motion while eliminating the effect of the vestibular system.