Comparative effectiveness of aerobic training intensities in chronic stroke: a network meta-analysis of randomized controlled trials

Objective This study aims to conduct a systematic review and network meta-analysis of randomized controlled trials (RCTs) to assess the effects of different aerobic exercise modalities on cardiopulmonary fitness and functional recovery outcomes [including VO 2 peak, 6-Minute Walk Test (6MWT), 10-Meter Walk Test (10MWT), Berg Balance Scale (BBS), and Time Up and Go (TUG)] in chronic stroke patients (≥3 months post-stroke). Methods This study employed a network meta-analysis (NMA) based on 33 RCTs involving 1,665 participants. The analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Network Meta-Analyses (PRISMA-NMA) guidelines. The primary outcomes assessed included VO 2 peak, 6MWT, 10MWT, BBS, and TUG. A consistency-based random-effects model was used to evaluate the effects of different exercise intensities on these outcomes. To assess the robustness of the findings, sensitivity analysis was performed by sequentially excluding each study and re-estimating the effect size of each intervention relative to Standard Of Care (SOC). This ensured that the overall results were not influenced by any single study. Additionally, linear regression analysis was conducted to evaluate the potential modifying effects of baseline gait speed, total intervention duration, baseline VO 2 peak and age on the therapeutic effects of the interventions. Results A total of 33 studies were included in the analysis, with 20 studies (n = 1,040) assessing VO 2 peak, 20 studies ( n = 1,113) on the 6MWT, 13 studies ( n = 566) on the 10MWT, and 12 studies ( n = 504) on the BBS and 7 studies ( n = 297) on the TUG. Both High-Intensity Interval Training (HIIT) and Moderate-Intensity Continuous Training (MICT) demonstrated the most significant effects on VO 2 peak, 6MWT, and 10MWT. For BBS or TUG, there are no statistically significant differences between the vast majority of interventions. Surface under the cumulative ranking curve (SUCRA) rankings tended to favor HIIT and MICT for VO 2 peak and walking outcomes, but confidence in comparative effects was limited. Evidence certainty assessed with CINeMA was predominantly low to very low across comparisons, particularly for BBS and TUG. Conclusion HIIT and MICT may improve cardiorespiratory fitness and walking performance after chronic stroke; however, the certainty of evidence is largely low or very low, and results should be interpreted cautiously. Effects on balance and TUG remain inconclusive. Systematic review registration https://www.crd.york.ac.uk/PROSPERO/view/CRD420251171092 , Identifier: CRD420251171092.