4×4 intervals beat steady work for VO₂max
With total work matched, 4-minute high-intensity intervals raised VO₂max more than moderate continuous training.
What they studied
- Design
- Randomised trial, four groups matched for total oxygen cost
- People
- 40 healthy, moderately trained men
- Duration
- 8 weeks, 3 sessions a week
- Groups
- Long slow distance (70% HRmax) · lactate threshold (85%) · 15/15 intervals · 4×4 min at 90–95% HRmax
What they found
- Both interval groups improved VO₂max significantly more than long slow distance or threshold training.
- 4×4 raised VO₂max by 7.2% (55.5 → 60.4 ml/kg/min); 15/15 by 5.5%.
- Stroke volume of the heart rose by about 10% after interval training, tracking the VO₂max gains.
How strong is the evidence
RCT
What this design cannot tell us:
- Small groups of young, moderately trained men only.
- Eight weeks shows the short-term response, not what happens over years.
What it means for your training
- Put 1–2 interval sessions a week on top of an easy aerobic base.
- 4 minutes at 90–95% HRmax with 3 minutes of easy recovery, repeated four times, is a proven template.
- Retest VO₂max every 8–12 weeks to see whether it is working for you.
Our summary of the published abstract. Read the original paper for full details.