11/09/2026
The Norwegian 4×4 is a high-intensity interval training workout designed to improve VO₂ max and cardiovascular fitness.
The classic protocol is:
4 minutes hard → 3 minutes easy → repeat 4 times
1. Warm-up: 8–10 minutes easy
2. 4 minutes hard: Aim for roughly 85–95% of maximum heart rate by the latter part of the interval. It should feel very hard, but controlled.
3. 3 minutes recovery: Easy walking, cycling, or jogging.
4. Repeat the 4-minute hard / 3-minute easy cycle 4 times.
5. Cool down: 5–10 minutes easy.
That gives you 16 minutes of hard work and about 12 minutes of recovery.
For you specifically, since you’ve been looking at your VO₂ max and mentioned sore legs, you don’t need to do this every time you want to improve your aerobic fitness. Easy Zone 2 walking/cycling plus 1–2 properly performed interval sessions per week can be a very effective combination.
And yes, skipping can be used for intervals, but the Norwegian 4×4 is traditionally performed with running, cycling, rowing, or another modality that allows you to sustain the required intensity for four minutes.