The Method Hybrid racing
How much of your cardio should be easy?
Most of it. Endurance athletes who do well keep about 80% of their sessions easy, and the rest hard.
StrongGood evidence, with a caveat worth knowing.
Updated . The Vanguard coaching team.
What most people miss
Endurance athletes who do well keep about 80% of their sessions easy and the rest hard, and pushing well-trained athletes to train harder has not shown a convincing long-term gain.1
How the hard part is shaped seems to matter less. When trials pit a polarized mix against a pyramid with more moderate work in the middle, the gains come out about even.2 The rule they share is the useful one: most of it easy.
What most people get wrong is what easy means. Every engine has a critical power, or on foot a critical speed: the hardest effort your body can hold in a steady state. Above it you are spending a fixed reserve, and the time you last is set by how much is left.3 Easy sits below it. Where your line sits is personal and can be measured, though the estimate depends on the test.4
The research
The papers behind the answer
Each one checked against the paper itself. The grade describes the strength of the evidence, never anyone's results.
Seiler, 2010 · Int J Sports Physiol Perform
Review of descriptive studies
About 80% of elite endurance athletes' sessions were easy and about 20% hard. Making well-trained athletes train harder showed no convincing long-term gain. The 80/20 counts sessions, not minutes.
Read the paper by Seiler, 2010 (opens in a new tab)Rosenblat, Watt, Arnold et al., 2025 · Sports Med
Network meta-analysis of individual data · 13 studies · 348 people
Polarized against pyramidal: no difference in VO2max or time trial. Competitive athletes may gain a little more from polarized, recreational athletes from pyramidal.
Read the paper by Rosenblat, Watt, Arnold et al., 2025 (opens in a new tab)Poole, Burnley, Vanhatalo et al., 2016 · Med Sci Sports Exerc
Review
Across species and exercise types, power and duration follow the same curve. Critical power is its floor, and above it the time you last is set by a fixed reserve of work.
Read the paper by Poole, Burnley, Vanhatalo et al., 2016 (opens in a new tab)Jones, Burnley, Black et al., 2019 · Physiol Rep
Review
Work right at critical power lasts about 20 to 30 minutes, the maximal lactate steady state usually sits a little below it, and the estimate depends on the test.
Read the paper by Jones, Burnley, Black et al., 2019 (opens in a new tab)
Research describes groups of people. Your coach will tell you how it applies to you.
From the floor
Conditioning in the app is set as a share of your own critical power or speed, per machine. An easy day has a ceiling it never crosses.
The Vanguard coaching team