Impact of isolated lumbar extension strength training on reducing nonspecific low back pain, disability, and improving function: a systematic review and meta-analysis

Nonspecific low back pain (LBP), a prevalent condition with a lifetime prevalence of up to 84%, presents a considerable burden on individuals and healthcare systems. Isolated lumbar extension (ILEX) has been studied for its ability to exercise the lumbar region with more controlled activation of the erector spinae and other paravertebral muscles. It aims to serve as a specific resistance training method to improve outcomes related to pain, disability, and physical functionality in adults with nonspecific low back pain (LBP). This systematic review and meta-analysis aimed to evaluate and summarize the effects of ILEX in alleviating pain, reducing disability, and improving physical functionality in adults with chronic LBP. Searches were conducted on October 14, 2024, across key databases, including PubMed, Scopus, and Web of Science. Eligibility criteria included adults (> 18 years old) with chronic LBP participating in resistance training focused on ILEX, with comparators comprising true control or active control groups, all from randomized clinical trials. The RoB2 was used to assess the risk of bias in the studies, while the GRADE scale was employed to evaluate the certainty of the evidence. The meta-analysis calculated Hedges' g effect sizes (ES) with 95% CIs and PIs for main outcomes, using the DerSimonian and Laird random-effects model to address inter-study variability, I-2 for heterogeneity, and the extended Egger's test for publication bias, all performed with SPSS Software. After screening, a total of 8 randomized studies were included, with 381 participants overall. The results indicated a significant favorable effect of ILEX compared to the true control group in pain-related outcomes (ES = - 0.633, p = 0.004). However, there was a non-significant effect of ILEX compared to the true control group in disability-related outcomes (ES = - 0.292, p = 0.190) and isometric strength outcomes (ES = 0.967, p = 0.150). The GRADE scale indicated that the certainty of the evidence is very low.ILEX significantly reduces pain intensity in individuals with low back pain, indicating its potential as an effective intervention, but its impact on disability and physical functionality is less consistent, warranting cautious use alongside pelvic stabilization to optimize rehabilitation outcomes.