Diaphragmatic dysfunction and activation interventions for chronic nonspecific low back pain: A systematic review and meta-analysis

BackgroundChronic nonspecific low back pain (CNLBP) is a leading cause of disability, with diaphragm dysfunction implicated in impaired spinal stability. However, systematic evidence on targeted interventions remains limited.ObjectiveTo quantify the efficacy of diaphragm-focused interventions on pain and function in CNLBP.MethodsThe systematic review/meta-analysis followed PRISMA-Cochrane guidelines. Analyzed randomized controlled trials (RCTs) assessing diaphragmatic interventions (manual therapy, respiratory training, neuromuscular re-education). Databases were searched until February 2025. Random-effects models and subgroup analyses were applied.ResultsMeta-analysis of 7 RCTs (n = 283) showed diaphragmatic interventions significantly reduced pain (overall SMD = -1.11, 95%CI: -1.52--0.71, <i>p</i> < 0.01). Diaphragmatic training (SMD = -1.37) and manual therapy (SMD = -1.25) were most effective, while neuromuscular re-education was not significant (SMD = -0.62). For disability, overall SMD was -0.83（95%CI: -1.14--0.52, <i>p</i> < 0.01, with manual therapy showing the largest effect size (SMD = -1.30), followed by diaphragmatic training (SMD = -0.69) and neuromuscular re-education (SMD = -0.47). Excluding one 4-week DNS study eliminated heterogeneity and increased pain effect to SMD = -1.24. Evidence certainty was low (GRADE).ConclusionDiaphragm-targeted interventions improve short-to-midterm pain and function. Future high-quality RCTs are needed to confirm long-term efficacy and standardize protocols.