Comparison of erector spinae and gluteus medius muscle thickness and activation in individuals with and without low back pain.

ABSTRACT

BACKGROUND: Dysfunctional patterns of the erector spinae (ES) and gluteus medius (GM) muscles often accompany episodes of low back pain (LBP). Rehabilitative ultrasound imaging (RUSI) has been used to measure ES and GM muscle thickness, however such measurements have not been compared in individuals with and without LBP. OBJECTIVES: To compare ES and GM muscle thickness and change in thickness utilizing RUSI in individuals with and without LBP. DESIGN: Cross-sectional comparison. METHODS: A volunteer sample of 60 adults with (n = 30) and without (n = 30) LBP was examined. Thickness measurements of the ES and GM at rest and during contraction were obtained by using RUSI during a single session. Statistical comparison was performed using ANCOVA. The demographic variable age was used as a covariate in the primary comparative analysis. RESULTS: Mean difference for age between groups was 5.4 years (95% CI 1.85, 8.94, p = 0.004). Average ODI score was 32.33±6.58 and pain level of 5.39±0.73 over the last 24 h in the symptomatic group. There was a statistically significant difference in the percent thickness change in both the ES, mean difference = -3.46 (95% CI -6.71, -0.21, p = 0.039) and GM, mean difference = -1.93 (95% CI -3.85, -0.01, p = 0.049) muscles between groups. CONCLUSIONS: Individuals with LBP may have reduced percent thickness change of the ES and GM muscles when compared to asymptomatic individuals.