VO₂max intervals on the bike: short or long?
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Two families of intervals
The authors of the 2021 study separate long intervals, about 3–5 minutes at high intensity, from short intervals, about 15–45 seconds at even higher intensity. The most common work:recovery ratio is 2:1 or 1:1. Both types have improved performance in earlier studies.1
The study: a week of closely spaced sessions
Seventeen male national-level cyclists (road and mountain bike) did five sessions in one week, then six days of standardised training, and were tested before and after.1
| Group | Session (study protocol) | People |
|---|---|---|
| Short intervals | 5 series of 12 × 30 s work, 15 s recovery; 3 min between series | 9 |
| Long intervals | 6 series of 5 min work; 2.5 min recovery between series | 8 |
Result: short intervals improved VO₂max more (difference 5.7%, confidence interval 1.3–10.3) and power at 4 mmol/L lactate (3.8%, 0.2–7.4). No difference in efficiency or 1-minute peak power. Power in the sessions was adjusted by perceived effort, and in the short group it came out higher.1
Illustrative example
One series of the short protocol lasts 12 × (30 s + 15 s) = 9 minutes: 6 minutes of work and 3 of recovery between repetitions. With five series that is 30 minutes of work and 15 of recovery within series, plus 12 minutes between series (four 3-minute breaks). Warm-up and cool-down are excluded. It is the study protocol, for already trained cyclists in a special week: not a starting point for beginners.
Organising the weeks
In another study, 19 trained cyclists compared 4 weeks with one week of five high-intensity sessions followed by three weeks with one session a week (block) against four weeks with two sessions a week. Volumes were similar. The block group improved VO₂max (+4.6%), peak power (+2.1%) and power at 2 mmol/L lactate (+10%); the traditional group showed no changes. Data from the abstract.2
A criterion the author uses
In a presentation by Rønnestad, time spent above 90% of VO₂max is given as a criterion to judge how much a session stimulates aerobic capacity, and repeated short intervals can give more time above that level than long intervals at the same mean power. These are slides summarising studies, not a paper.3
Limits
- Small groups (8–10 people), all men, well-trained cyclists: not valid for beginners or for women.
- They measure laboratory indicators (VO₂max, power at lactate), not race results.
- The five-session week is a special block followed by recovery; it is not a normal week.
- The work:recovery comparison belongs to the study: you cannot conclude which format is better in every context.
- For intensity distribution over the whole season see the cycling intensity sheet.
Sources
- Rønnestad et al., Superior Physiological Adaptations After a Microcycle of Short Intervals Versus Long Intervals in Cyclists, 2021. full text. Read.
- Rønnestad, Hansen, Ellefsen, Block periodization of high-intensity aerobic intervals provides superior training effects in trained cyclists, Scand J Med Sci Sports 2014. PubMed. Abstract only.
- Rønnestad, Optimizing high-intensity aerobic training sessions (slides). science-cycling.org. Read, as a summary only.
Sources read on 29 October 2026.