Stephen SeilerPhD · exercise physiologist · Professor, University of Agder
Mostly easy and long, with two hard sessions a week
What it rests onDescriptive studies of nationally and internationally competitive endurance athletes, plus intensification trials whose results he calls equivocal
Source: journals.humankinetics.com ↗
Martin J. GibalaPhD · exercise physiologist, McMaster University
Short and hard can carry the health outcomes on a fraction of the time
What it rests onRandomised comparison in sedentary men, Gillen and colleagues, PLoS One 2016, Gibala senior author
Source: pmc.ncbi.nlm.nih.gov ↗
The positions are not talking about the same people or the same outcome. Gillen studied sedentary men and cardiometabolic health markers. Seiler's claim is about already well-trained endurance athletes and competitive performance over years. Neither result contradicts the other, and the honest answer for a user depends on which of those two people they are.
Both hold that some high-intensity work belongs in almost everyone's week, and both reject the idea that a single session's acute response predicts the long-term outcome.
A long-duration trial in trained recreational athletes, tracking performance rather than health markers, comparing a genuinely polarised distribution against a low-volume high-intensity programme.
You do, and your call is dated, kept, and yours to change. Follow the people you already trust and what they publish turns into a short daily practice.
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