Gym bay · 4×4:00
Norwegian 4×4
Helgerud 2007. Holdable hard ~90–95% HRmax. Not all-out Tabata.
Treadmill or bike, one named Saturday or a weekday with time.
Other venue: Home floor
Inputs
- Treadmill, bike, or rower
- Timer
Rounds
- 4:00 at a hard they can hold.
- 3:00 easy.
- ×4.
This is the VO2 clock. It is not a fat-loss claim.
Chest pain, unusual shortness of breath, dizziness, or a known uncleared heart / metabolic / renal condition: stop. Get clearance. Unsupervised HIIT is not cardiac rehab.