Related Experiment Video
Updated: Aug 6, 2026
08:27
A Real-World High-Intensity Interval Training Protocol for Cardiorespiratory Fitness Improvement
Published on: February 22, 2022
Comparison of high-intensity interval training protocol designs on accumulated time ≥ 90% V̇O₂max: a network
Steffen Held1, Ludwig Rappelt2, Florian Micke3
1Department of Sport and Management, IST University of Applied Sciences, Duesseldorf, Germany. sheld@ist-hochschule.de.
BMC Sports Science, Medicine & Rehabilitation
|July 21, 2026
Summary
High-intensity interval training (HIIT) protocols do not show clear differences in accumulated time at 90% maximal oxygen uptake (V̇O₂max). Decreased-duration and varied-intensity HIIT ranked highest but require further investigation due to study limitations.
Area of Science:
- Exercise Physiology
- Sports Science
- Cardiovascular Adaptations
Background:
- Accumulated time spent at ≥90% maximal oxygen uptake (V̇O₂max) is a key stimulus for aerobic adaptations during high-intensity interval training (HIIT).
- Understanding the impact of different HIIT protocol structures on this physiological stimulus is crucial for optimizing training.
- Network meta-analysis provides a robust framework for comparing diverse training interventions using direct and indirect evidence.
Purpose of the Study:
- To compare various high-intensity interval training (HIIT) protocol structures based on accumulated time at ≥90% maximal oxygen uptake (V̇O₂max).
- To utilize direct and indirect evidence from controlled HIIT studies in healthy athletes.
- To identify potential differences in physiological stimuli across distinct HIIT programming strategies.
Main Methods:
- Systematic literature search across PubMed, Web of Science, and SPORTDiscus up to January 31st, 2026.
- Inclusion of controlled HIIT studies reporting accumulated time at ≥90% V̇O₂max in healthy athletes.
- Frequentist network meta-analysis (NMA) using standardized mean differences (SMD) with even long intervals as the reference, employing random effects models and assessing heterogeneity and inconsistency.
Main Results:
- Nineteen publications with 20 study units and 240 athletes were analyzed, revealing substantial heterogeneity and inconsistency.
- No significant differences were found between any HIIT approaches and the reference condition (even long intervals) for accumulated time at ≥90% V̇O₂max.
- Decreased-duration (SMD=0.87) and varied-intensity (SMD=0.54) protocols showed the highest point estimates, while 1:1 work-to-rest blocks had the lowest (SMD=-0.68).
Conclusions:
- No specific HIIT protocol structure demonstrated clear superiority in achieving accumulated time at ≥90% V̇O₂max.
- While decreased-duration and varied-intensity protocols ranked higher, these findings are exploratory due to non-significant comparisons, heterogeneity, inconsistency, and sparse data.
- Protocol selection should consider practical factors like feasibility, athlete characteristics, and workload matching over theoretical rankings alone.
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