SynthesisBMC sports science, medicine & rehabilitation2026
Comparison of high-intensity interval training protocol designs on accumulated time ≥ 90% V̇O₂max: a network meta-analysis.
Synthesis in BMC sports science, medicine & rehabilitation, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
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Abstract
backgroundAccumulated time ≥ 90% of maximal oxygen uptake (V̇O
methodsWe systematically searched PubMed, Web of Science, and SPORTDiscus up to January 31st, 2026 for controlled HIIT studies reporting accumulated time ≥ 90% V̇O₂max in healthy athletes. HIIT protocols were classified using predefined operational rules based on interval duration, work-to-rest structure, intensity pattern, and within-session progression. We conducted a frequentist NMA using standardized mean differences (SMD) within a random effects model, with even long intervals as the reference condition, and added local inconsistency and contribution diagnostics.
resultsNineteen publications contributed 20 study units, including 240 athletes (25.5 ± 5.3 years; V̇O₂max 60.5 ± 8.1 ml·kg⁻¹·min⁻¹). The network demonstrated substantial heterogeneity and significant inconsistency (I² = 69.2%, 95% CI 49.9% to 81.0%; total Q = 55.12, df = 17, p < 0.0001; between-design Q = 20.78, df = 6, p = 0.002). None of the HIIT approaches differed significantly from even long intervals in accumulated time ≥ 90% V̇O₂max. Point estimates were highest for decreased-duration (SMD = 0.87, 95% CI -0.30 to 2.04) and varied-intensity protocols (SMD = 0.54, 95% CI -0.42 to 1.49), whereas 1:1 blocks showed the lowest point estimate (SMD = -0.68, 95% CI -1.40 to 0.04). P-score ranking favored decreased-duration (89.6%), followed by varied-intensity (76.7%) and decreased-intensity protocols (68.4%), while 1:1 blocks ranked lowest (2.8%).
conclusionNo HIIT protocol structure showed clear superiority for accumulated time ≥ 90% V̇O₂max. Decreased-duration and varied-intensity protocols ranked highest, but these rankings were exploratory because all reference comparisons were statistically non-significant and the network showed substantial heterogeneity, significant inconsistency, and sparse evidence for several nodes. Protocol selection should therefore prioritize feasibility, athlete characteristics, and workload-matching considerations rather than ranking alone.
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