Comparison of Interval Training Methods on Athletes' Oxygen Uptake: A Network Meta-Analysis

This 2025 network meta-analysis is one of the most comprehensive comparisons of interval training methods ever conducted, analyzing 51 studies involving 1,261 athletes to rank and compare the relative effectiveness of different interval training protocols for improving VO2max. The network meta-analysis design allowed researchers to compare protocols that had never been tested head-to-head in a single study — including sprint interval training (SIT), high-intensity interval training (HIIT), and several variants — by drawing indirect comparisons across the entire body of evidence simultaneously.

Sprint interval training — defined as efforts of 30 seconds or less with recovery periods under 97 seconds — ranked among the most effective protocols for VO2max improvement. The analysis found that three sessions per week sustained over three to six weeks was sufficient to produce significant VO2max gains across the studies reviewed. Longer training blocks did not consistently produce proportionally larger gains, suggesting that the body's initial adaptation to sprint stimuli is both rapid and substantial. The dose of intensity, not the volume of training, was the primary predictor of outcome.

For men over 50, this network meta-analysis provides a practical roadmap. Brief sprint intervals — 30 seconds or less — three times per week for as few as three weeks can meaningfully improve VO2max. This is not a long-term commitment before you see results. The study also found minimal evidence that more complex interval protocols outperformed simple, short sprints — meaning that straightforward approaches like hill sprints or track repeats are as effective as sophisticated training designs. Simplicity combined with intensity is the formula that works.