A scoping review published this spring has done what no individual paper has managed in years: pulled together more than half a century of VO2max training research into a single accounting of who has been studied, on what protocols, and to what effect. Indexed at PubMed Central in February, the review covers 617 studies and concludes that the evidence base is far less unified than the popular reading of the field would suggest. Moderate continuous work, not high-intensity intervals, remains the most heavily researched stimulus — and the gap between training fashions and training data is wider than it looks from a magazine cover.
The review's central finding is procedural rather than prescriptive. Of the 617 studies it screened, the majority used moderate-intensity continuous training (MICT) protocols, while smaller and far less consistent slices of the literature examined high-intensity interval training (HIIT), sprint interval training (SIT) or combinations of the three. The authors flag that this skew makes the often-quoted superiority of interval work harder to sustain than coaching shorthand implies; the data shows that intervals can produce similar or larger VO2max gains over short windows, but the breadth of population and protocol variety is much smaller.
For runners, the most useful detail in the review is who has actually been measured. Untrained and recreationally active adults dominate the populations sampled; well-trained endurance runners are comparatively under-studied, and elite samples are vanishingly rare. The implication is that headlines extrapolating from sedentary improvers to marathoners are jumping a gap the source data does not bridge. The same caveat applies to the duration of intervention: most protocols ran 8 to 12 weeks, leaving very little high-quality evidence on how VO2max responds across an entire training year.
The review lands at a useful moment for the broader training-science discussion. The polarised- and pyramidal-training debate has been productive but increasingly internecine, and the parallel emergence of AI-generated marathon plans — covered in March's Boston Marketing Bulletin study — has raised the stakes of getting the underlying evidence base right. A review that maps the field rather than relitigating it is a useful corrective; future work, the authors note, should weight more carefully toward longer interventions in trained runners and toward the responder-profile work that has begun to emerge in pyramidal-training research.
For practical purposes the takeaway is uncontroversial. VO2max responds to a wide range of stimuli; the well-evidenced floor is moderate continuous running, the well-evidenced ceiling is intervals at or above the velocity at VO2max, and the meaningful work for most non-elite runners sits in mixing the two over months rather than tweaking the ratio over weeks. The 617-study review does not prescribe a programme. It does, however, give coaches and runners a much clearer sense of what the science can and cannot tell them yet.