A study published in the journal Sports Medicine in 2026 has added fresh weight to one of distance running’s oldest debates: how much the shape of a training block, rather than any single workout, decides what happens on race day. Drawing on a large sample of marathoners, the research examined how changes in training volume and training frequency in the weeks before the Boston Marathon related to finishing performance, offering a data-led look at habits that runners often argue about on feel alone.
The headline finding will reassure the high-mileage faithful. Runners who sustained greater weekly volume in the build-up tended to record faster times, consistent with decades of coaching orthodoxy that places aerobic mileage at the centre of marathon preparation. Importantly, the relationship was not limitless: the gains from piling on more miles appeared to flatten at the upper end, a reminder that the dose-response curve bends and that more is not indefinitely better.
Frequency emerged as a factor in its own right. Spreading training across more sessions each week was associated with stronger performances, even when total volume was accounted for, pointing to the value of consistency and regular aerobic stimulus over a smaller number of longer, harder efforts. For time-pressed amateurs, the implication is encouraging: several manageable runs may serve a marathon build better than a couple of punishing ones.
The usual caveats apply, and they matter. This was an observational analysis, not a controlled trial, so it can map associations but cannot prove that volume or frequency directly caused faster times; fitter, more committed runners may simply train more. Self-selection, differing experience levels and the ever-present risk of injury when mileage climbs too quickly all complicate the picture, and the long-standing caution against sudden jumps in load remains sound advice.
For the everyday runner, the practical takeaways are familiar but newly evidenced. Build volume gradually, prioritise consistent weekly frequency over occasional heroics, and respect the point of diminishing returns rather than chasing ever-bigger weeks. Read alongside recent work on strength training and running economy, the study reinforces a quietly unglamorous truth of marathon preparation: steady, repeatable habits, accumulated over months, tend to outperform dramatic gestures made in the final weeks.