Abstract
OBJECTIVE: This study conducted a thorough review and meta-analysis to examine how respiratory muscle training (RMT) affects lung function recovery in individuals with spinal cord injury (SCI). METHODS: We conducted a systematic review of Randomized Controlled Trials (RCTs) examining the effects of RMT on lung function in patients with SCI. The search included databases such as PubMed, Embase, The Cochrane Library, Scopus, and Web of Science up to October 2025. The experimental group received RMT as the main intervention, while the control group received either no treatment, a placebo, or conventional rehabilitation. Outcome measures included Forced Expiratory Volume in the first second (FEV(1)), Forced Vital Capacity (FVC), Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure (MEP), Peak Expiratory Flow (PEF), Minute Ventilation Volume (MVV), Total Lung Capacity (TLC), Inspiratory Capacity (IC), and Vital Capacity (VC). Two reviewers independently screened, extracted data, and assessed bias. Meta-analysis was conducted using RevMan 5.3 software, and the quality of included studies was evaluated using the Cochrane bias risk assessment tool and the Physical Therapy Evidence Database scale. The reporting of this study followed the PRISMA guidelines and was registered with PROSPERO (ID: CRD42024627736). RESULTS: In this meta-analysis, 25 RCTs were included, comprising a total of 679 patients. The meta-analysis showed that compared with conventional rehabilitation, respiratory muscle training significantly improved FEV(1) (p < 0.0001), FVC (p = 0.0001), MIP (p < 0.00001), MEP (p = 0.0004), PEF (p < 0.00001), MVV (p < 0.0001), TLC (p = 0.05), VC (p = 0.04), and their differences were statistically significant. However, IC (p = 0.40) was not statistically significant. Subgroup analyses showed that resistive training and surface electromyography biofeedback training were effective for improving FEV(1) and FVC, while threshold training significantly improved MVV. CONCLUSION: This meta-analysis provides strong evidence that RMT is an effective intervention for enhancing respiratory muscle strength and key parameters of pulmonary function in individuals with SCI. Further research with robust methodologies and extensive sample sizes is needed to validate this finding.