Running at 100% of vVO₂max
The 4 × 4 is run just below your vVO₂max, not at it: four minutes at full vVO₂max is close to your limit, and the fourth rep falls apart. The recent studies from Helgerud's group prescribe about 95%.
RunningVO2maxBeginner 50 min
Norwegian 4 × 4 for runners (Helgerud)
Norwegian 4x4 intervals: four 4-minute reps at 93–97% of your vVO₂max, with 3 minutes of jogging between each. 16 minutes of work in a 50-minute session. One of the most studied formats for raising VO₂max, and one of the simplest to follow.
Session profile10 blocks
At a glance
- Duration
- 50 min
- Main target
- 93–97%vVO₂max5 Z5 · VO₂max
- Time at target
- 16 min
- Estimated load
- 57
- Structure
- 4 × 4′ at 93–97% vVO₂max, 3′ recovery
- Level
- Beginner
- Equipment
- GPS watch · Heart rate monitor · Track (optional)
The session in detail
vVO₂max
Time in zone
- Z129 min
- Z25 min
- Z516 min
What the targets mean
| Target | Zone | Time | vVO₂max 14 km/h | vVO₂max 16 km/h | vVO₂max 18 km/h |
|---|---|---|---|---|---|
| 93–97% | 5VO₂max | 16 min | 4:36/km–4:25/km 868–905 m per rep | 4:02/km–3:52/km 992–1035 m per rep | 3:35/km–3:26/km 1116–1164 m per rep |
| 58–65% | 1Recovery | 9 min | 7:23/km–6:36/km 406–455 m per rep | 6:28/km–5:46/km 464–520 m per rep | 5:45/km–5:08/km 522–585 m per rep |
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What this session is for
The 4 × 4 makes your heart work hard for several minutes at a time to raise your VO₂max. Each rep is long enough for your heart rate to reach 90 to 95% of its maximum by about the third minute and stay there to the end; the 3 minutes of jogging let you go again four times.
Few sessions have been studied as much. Jan Helgerud's group tested it in moderately trained men in 2007, then in well-trained men and women in 2023: each time, VO₂max rose more than with the other training compared. One caveat: these studies come from a single research group, in young adults.
Who it's for
Regular runners, including less experienced ones: the pace stays just under your vVO₂max, and the recovery is generous. It makes a good first long-rep session, after a few rounds of 1-minute reps or 30/30s. You need a recently measured vVO₂max, or a heart rate strap to work by heart rate, as in the original protocol.
When to do it
One or two sessions of this kind a week is a common guideline. Put them after an easy day or a rest day, never the day before a long run, another hard session or a race. To progress, start with 3 × 4 minutes, move to 4 × 4, then cut the recovery to 2 minutes or move to 4 × 5 minutes.
How to do it
Warm-up
15 min10′ at 60–65% vVO₂max + 5′ at 66–72% vVO₂max
10 minutes of easy running at 60–65% of vVO₂max, then 5 minutes at 66–72%. Add two or three strides if you like: the first rep should start on legs that are awake.
Main set
25 min4 × 4′ at 93–97% vVO₂max, 3′ recovery
Four 4-minute reps at 93–97% of your vVO₂max, with 3 minutes of jogging at 58–65% between each. At 16 km/h that's 4:02 to 3:52/km, or 992 to 1,035 metres per rep: two and a half laps of a track. Build into the pace over the first minute, without going off flat out, then hold it. By heart rate, aim for 90 to 95% of your maximum from the third minute. The recovery jog covers 464 to 520 metres: jog it, don't walk.
Cool-down
10 min10′ at 55–65% vVO₂max
10 minutes of very easy running at 55–65% of vVO₂max. Compare your four distances: if the last is clearly shorter than the first, you went off too fast, or your reference vVO₂max is set too high.
How it should feel
Hard, but not a sprint. Your breathing gets properly quick from the second minute, and the last minute of each rep takes concentration. The third rep is the one where you start quietly renegotiating the total. Guide: 7 to 8 out of 10.
Common mistakes
Walking the recoveries
The 3 minutes are jogged, at 58–65% of vVO₂max: an active recovery, at about 70% of maximum heart rate in the original protocol. Walking lets your heart drop too far, and each rep starts from lower down.
Pacing by heart rate from the gun
Your heart takes two to three minutes to climb. Chase 90% of your maximum in the first minute and you'll go off far too fast. Set your pace by speed early on, and let heart rate confirm it at the end of the rep.
Doing it too often
The three sessions a week in the studies were part of an 8-week research protocol. In a full plan with a long run and other sessions, one or two is plenty.
When to skip it
Before you start
- A recently measured vVO₂max, or a heart rate strap and your maximum heart rate.
- Being able to run 30 minutes easy without difficulty.
Skip it if
- You have a known heart condition, or doubts about your health: get medical advice before hard efforts.
- You have pain, a recent injury or heavy fatigue.
- A long run, another hard session or a race is planned for the next day.
Origin and evidence
Level of evidence
Good evidenceLevel 4 of 5
Helgerud and colleagues (Med Sci Sports Exerc 2007), 40 moderately trained men, 8 weeks at 3 sessions a week, four groups with equal work: VO₂max +7.2% with 4 × 4 minutes (90–95% of maximum heart rate, 3 minutes of active recovery at 70%) and +5.5% with a 15/15, more than with training at 70% and 85% of maximum heart rate. Hov and colleagues (Scand J Med Sci Sports 2023), 48 well-trained men, 4 × 4 minutes at about 95% of vVO₂max: VO₂max +6.5 ± 2.4%, more than with sprint protocols. Helgerud and colleagues (Scand J Med Sci Sports 2023), 81 well-trained women: +7.3 ± 3.1%, with no injuries. The 93–97% range translates the instruction of about 95%; the recovery at 58–65% is an estimated equivalent of 70% of maximum heart rate; the warm-up and the cool-down are Wattson choices. Bottom line: a high level of evidence (randomised trials), but in young adults and from a single research group.
Sources
- Helgerud J. et al., Med Sci Sports Exerc 2007;39(4):665-671
- Hov H. et al., Scand J Med Sci Sports 2023;33(2):146-159
- Helgerud J. et al., Scand J Med Sci Sports 2023;33(11):2193-2207
Frequently asked questions
What pace should I run Norwegian 4x4 intervals at?
At 93–97% of your vVO₂max. At 14 km/h, 4:36 to 4:25/km, or 868 to 905 metres in 4 minutes; at 16 km/h, 4:02 to 3:52/km; at 18 km/h, 3:35 to 3:26/km, or 1,116 to 1,164 metres. By heart rate, aim for 90 to 95% of your maximum from the third minute.
Do Norwegian 4x4 intervals work?
It's one of the most studied formats. In 40 moderately trained men, it raised VO₂max over 8 weeks more than endurance or threshold training with equal work. The 2023 studies, in well-trained men and women, found similar gains. All of them come from the same research group.
Jog or walk the 4x4 recoveries?
Jog. The protocol has 3 minutes of active recovery at about 70% of maximum heart rate, which is 58–65% of vVO₂max. That jog keeps your heart high enough for the next rep to reach the right intensity quickly.
How many 4x4 sessions a week?
One or two, after an easy day: a common guideline. The studies used three a week for 8 weeks, but they were research protocols. Leave room for your long run and easy runs, which make up most of your volume.
Norwegian 4x4 or 15/15?
In Helgerud's 2007 study both raised VO₂max, the 4 × 4 slightly more than the 15/15 with equal work. The 4 × 4 asks you to hold a long effort; the 15/15, to keep up a quick recovery. Alternating them over a block is a good way to mix things up.
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