Do rocker-sole shoes influence postural stability in chronic low back pain? A randomised trial

C Sian MacRae; Duncan Critchley; Matthew Morrissey; Adam Shortland; Jeremy S Lewis

doi:10.1136/bmjsem-2016-000170

Do rocker-sole shoes influence postural stability in chronic low back pain? A randomised trial

BMJ Open Sport Exerc Med. 2016 Oct 19;2(1):e000170. doi: 10.1136/bmjsem-2016-000170. eCollection 2016.

Authors

C Sian MacRae¹, Duncan Critchley², Matthew Morrissey³, Adam Shortland⁴, Jeremy S Lewis⁵

Affiliations

¹ College of Health and Life Sciences, Brunel University, Uxbridge, UK; Therapy Services, Chelsea and Westminster Hospital NHS Foundation Trust, London, UK.
² Academic Department of Physiotherapy and Division of Health and Social Care Research , King's College London , London , UK.
³ Faculty of Health Sciences , University of Ljubljana , Ljubljana , Slovenia.
⁴ Guy's and St Thomas' NHS Foundation Trust, One Small Step Gait Laboratory, London, UK; Biomedical Engineering, King's College London, London, UK.
⁵ Department of Allied Health Professions, University of Hertfordshire, Hatfield, UK; Musculoskeletal Services, Central London Community Healthcare NHS Foundation Trust, London, UK.

Abstract

Background: People with chronic low back pain (CLBP) demonstrate greater postural instability compared with asymptomatic individuals. Rocker-sole shoes are inherently unstable and may serve as an effective balance training device. This study hypothesised that wearing rocker-sole shoes would result in long-term improvement in barefoot postural stability in people with CLBP.

Methods: 20 participants with CLBP were randomised to wear rocker-sole or flat-sole shoes for a minimum of 2 hours each day. Participants were assessed barefoot and shod, over three 40 s trials, under 4 posture challenging standing conditions. The primary outcome was postural stability assessed by root mean squared error of centre of pressure (CoP) displacement (CoP_{RMSE AP}) and mean CoP velocity (CoP_VELAP), both in the anteroposterior direction, using force plates. Participants' were assessed without knowledge of group allocation at baseline, 6 weeks and 6 months (main outcome point). Analyses were by intention-to-treat.

Results: At 6 months, data from 11 of 13 (84.6%) of the rocker-sole and 5 of 7 (71.4%) of the flat-sole group were available for analysis. At baseline, there was a mean increase in CoP_{RMSE AP} (6.41 (2.97) mm, p<0.01) and CoP_VELAP (4.10 (2.97) mm, p<0.01) in the rocker-sole group when shod compared with barefoot; there was no difference in the flat-sole group. There were no within-group or between-group differences in change in CoP parameters at any time point compared with baseline (1) for any barefoot standing condition (2) when assessed shod eyes-open on firm ground.

Conclusions: Although wearing rocker-sole shoes results in greater postural instability than flat-sole shoes, long-term use of rocker-sole shoes did not appear to influence postural stability in people with CLBP.

Keywords: Biomechanics; Exercise rehabilitation; Lumbar spine; Randomised controlled trial.