← EXERCISE LIBRARYConditioning
Four-By-Four VO2max Intervals
Four four-minute hard efforts with three-minute active recoveries. A well-studied Norwegian protocol for raising maximal aerobic capacity in trained and untrained people alike.
- 01Warm up with ten minutes of progressively faster easy running.
- 02Run four minutes at RPE 8 to 9, hard enough that speaking is limited to single words.
- 03Jog or walk three minutes at genuinely easy effort until breathing settles.
- 04Repeat for four total work intervals, aiming to finish the last one at the same effort as the first.
- 05Cool down with ten minutes easy and run this session no more than twice a week.
- 01First interval is the pacing test, match it three more times.
- 02You should be able to say one word, not three.
- 03Keep the recovery honest and easy.
- 01Going out at maximum on interval one, which makes the remaining three efforts progressively slower.
- 02Running the recoveries too hard, which prevents you from reaching the target effort again.
- 03Stacking these sessions back to back, which produces fatigue without allowing the adaptation.
Note: Reference material, not a prescription. Load, volume and whether this movement suits you at all depends on your assessment — if something hurts, stop and get it looked at.