Day 23 — Norwegian 4×4 intervals
Norwegian 4×4 is the most studied protocol for raising VO2max in untrained adults — Helgerud et al. 2007 showed ~10% gains in 8 weeks. Week 4 — taper. Cut 25% volume, hold intensity, prep for re-test. Volume cut 25% this week — let the engine consolidate.
Today's exercises
Norwegian 4×4 (Run)
Norwegian 4×4: 10 min warm-up, 4 × (4 min hard / 3 min easy), 5 min cool-down.
- 4 rounds: 4 min HARD (85–95% HRmax) / 3 min easy
- Hard intervals should leave you unable to talk
- 10 min warm-up + 5 min cool-down bracket the set
Form reference: Wikimedia Commons · Public domain
Not medical adviceVO2max protocols can be intense. Consult your doctor before starting any exercise plan, especially if you have a pre-existing condition. Stop immediately if you feel chest pain, dizziness, or unusual shortness of breath.