Training-Induced Adaptations in Skeletal Muscle Oxygenation in Athletes and Healthy Individuals: A Systematic Review...

Liu, J, Guo, J, Than, MT, Bleakney, AW, Elliott, JR, and Jan, Y-K. Training-induced adaptations in skeletal muscle oxygenation in athletes and healthy individuals: a systematic review and network meta-analysis. J Strength Cond Res XX(X): 000-000, 2026-Near-infrared spectroscopy (NIRS) provides real-time indices of skeletal muscle O 2 delivery and utilization during exercise, yet no quantitative synthesis has simultaneously compared the relative effectiveness of multiple exercise training modalities on NIRS-derived outcomes. To conduct the first systematic review and network meta-analysis (NMA) comparing and probabilistically ranking exercise training modalities for their effects on NIRS-derived skeletal muscle deoxygenation and reoxygenation in athletes and healthy nonathletes. Five electronic databases were searched from inception to February 2026. Eligible studies reported NIRS-derived outcomes before and after structured exercise training with a concurrent control condition. Hedges' g was computed from change score data and pooled using frequentist random-effects NMA. Interventions were ranked by p -scores. Prespecified subgroup analyses examined training status as a potential moderator. This review was prospectively registered on PROSPERO (CRD420261335304). Twenty-seven studies (16 randomized controlled trials and 11 nonrandomized designs) were included. No training modality reached statistical significance relative to nonexercise control in either outcome domain, with all 95% confidence intervals crossing zero. Despite this, exploratory p -score rankings tended to position blood flow restriction training (BFR) highest across both the deoxygenation ( p -score = 0.75) and reoxygenation ( p -score = 0.80) constructs, followed by hypoxic training for reoxygenation ( p -score = 0.68). Small-sided games were evaluated in only a single study and were therefore reported descriptively rather than ranked. Athlete-only subgroups showed greater between-study heterogeneity than nonathlete subgroups (I 2 = 77.7 vs. 48.9% for deoxygenation), a preliminary observation that training status may be associated with greater adaptive variability, requiring confirmation in adequately powered studies. After excluding single-study nodes, blood flow restriction training was the highest-ranked modality across both outcome constructs; however, no comparison reached statistical significance, and all rankings should be interpreted as exploratory and hypothesis-generating rather than as guidance for practice. The divergent rankings across outcome constructs are consistent with the possibility that deoxygenation and reoxygenation indices capture different adaptive mechanisms and should not be treated as interchangeable monitoring tools. Standardized NIRS protocols and prospectively registered multiarm trials are needed to strengthen the evidence base.