Effect of unstable shoes on trunk posture during standing and gait in chronic low back pain

Chronic low back pain (CLBP) is a common painful condition affecting particularly medical hospital staff. Wearing unstable shoes could be proposed as an alternative treatment as a pain decrease was observed in a recent study. A six-week treatment showed pain decrease that could be linked to a more vertical trunk posture. Therefore, the aim of this study was to evaluate if unstable shoes allow a more vertical posture of the trunk in the sagittal plane explaining this decrease in pain after six weeks of wearing. Forty CLBP hospital employees were randomly distributed in intervention (IG, n = 17) and control group (CG, n = 16) wearing respectively unstable and stable shoes. Gait and orthostatic trunk kinematics were recorded before and after six weeks in barefoot and shoes conditions. IG participants were defined responders (R-IG, n = 8) if a pain reduction ≥ 2 points (difference in values obtained with a visual analogue scale pain scale (VAS) before and after 6 weeks) was observed; otherwise, IG participants were defined non-responders (NR-IG, n = 9) (pain reduction < 2). IG had a tendency to show a trunk more vertical than CG in orthostatic position and R-IG had a tendency to show a trunk more vertical than NR-IG during gait. Due to the small observed differences, it is difficult to conclude on the effect of unstable shoes on trunk posture and gait of CLBP patients after six weeks of wearing