Proprioceptive training improves postural control in people with low back: a proof-of-concept study

Abstract

Background and Aim Low back pain (LBP) is the leading cause of disability worldwide. Previous studies suggested that people with LBP showed impaired proprioceptive postural control, which could be related to both the onset and maintenance of LBP. However, the reversibility of disturbed proprioceptive postural control in people with LBP remains unclear. Therefore, this study investigated the effect of proprioceptive training on (1) proprioceptive postural control and (2) pain and disability in people with LBP.

Methods Twenty-five people with recurrent LBP (14 men, 11 women; Age= 47 ± 10 years; BMI= 24.1 ± 2.3) participated in an 8-week proprioceptive training. Exercises aimed to promote variability in sensing, discriminating and localizing lumbar postures, movements and muscle activation. Participants were instructed to implement these exercises in their daily lives. Postural control was evaluated during standing on stable and unstable ground, with vision occluded. Muscle vibration, a strong stimulus to muscle spindles, was applied to the ankle and back muscles. Center of pressure (COP) displacements indicated the magnitude of proprioceptive reliance on the vibrated muscle, and were measured on a force plate (Kistler). A ratio of COP displacement to ankle versus back muscle vibration was calculated. Additionally, self-reported percentages of change in pain and disability (scale from 0 to 100% improvement), and the Modified Low Back Pain Disability Questionnaire (MDQ) evaluated the clinical effect of training. Non-parametric statistics were used, since data was non-normally distributed.

Results After training, patients showed increased COP displacement in response to back muscle vibration on both stable (p= 0.036) and unstable ground (p= 0.043). Moreover, after training, the ratio of ankle versus back muscle vibration indicated a more dominant reliance on lumbar proprioceptive use, on unstable ground (p= 0.034). In addition, clinical outcomes significantly improved after training for the MDQ (pre training: 27 ± 10; post training 14 ± 10, p< 0.001), with high self-reported change in disability (51%) and pain (49%).

Conclusions Proprioceptive training increased lumbar proprioceptive reliance during standing on both stable and unstable ground. This could potentially be explained by increased lumbar muscle spindle sensitivity, resulting in enhanced lumbar segmental control. Moreover, patients showed a more dominant reliance on lumbar proprioceptive use on unstable ground, instead of a typical rigid ankle control strategy in people with LBP. This suggested improved adaptability of postural control to the environment induced by proprioceptive training. Since both pain and disability improved after training, proprioceptive training could be considered in the treatment for people with recurrent LBP. Future studies should explore long term effects of training and whether distinct patient characteristics may improve responsiveness to training.