Erector Spinae Muscle Activation During Forward Movement in Individuals With or Without Chronic Lower Back Pain: A Systematic Review and Meta-analysis

OBJECTIVE: To investigate the differences between erector spinae muscle activation in healthy individuals and patients with Chronic Lower Back Pain (CLBP) by conducting (a) systematic review and (b) meta-analysis. DATA SOURCES: PubMed, ScienceDirect, SPORTDiscus, and Google Scholar were used to conduct the searches, which included studies up to the 31st of March 2023 with no start date specified. STUDY SELECTION: Any study otherwise meeting eligibility criteria was included if it reported either (1) a standard mean difference effect size; or (2) the means, SDs, and sample sizes for both the patient group and the comparator group. DATA EXTRACTION: A total of 7 case control trials were used for the systematic review and meta-analysis. DATA SYNTHESIS: The systematic review and meta-analysis revealed that total standardized mean difference in erector spinae muscle activation between healthy individuals vs patients with CLBP expressed in % maximum voluntary isometric contraction was 0.48 (95% confidence interval=0.21-0.74; P<.001) with the heterogeneity being I(2)=0% (P=.890). The electromyography (EMG) outputs showed significant differences in activation levels between the healthy and CLBP cohorts (P<.001). CONCLUSIONS: A small effect size was found in the meta-analysis. The muscle activation levels of the erector spinae during forward propulsion were higher in CLBP individuals compared with healthy cohorts. The findings provide more clarity about the muscles that were the focus of previous research, what procedures were used to evaluate muscular contributions and what speeds the participants were moving at during the test sessions. Given the limited methodological quality of the included studies, the findings should be interpreted with caution. Future research should evaluate the effect of other factors such as walking distance and any changes in walking surfaces and gradients (ie, non-flat surfaces).