Norwegian 4×4 Cycling

Norwegian 4×4 is an indoor cycling app for smart trainers. It runs the Norwegian 4×4 interval protocol — four 4-minute work blocks at 90–95% of maximum heart rate, with 3-minute active recovery in between — and controls your trainer's resistance automatically so your heart rate stays in the zone. This is not a running app. Watts, cadence, ERG control — built for the bike. HEART-RATE ERG CONTROL Most training apps set a fixed wattage and leave you to manage your heart rate. Norwegian 4×4 works the other way: it adjusts target watts every block to land your HR in the 90–95% HRmax band. • Adjustments happen in small steps — no jarring shifts mid-block • Cardiac drift across blocks is detected and compensated automatically • Cadence protection prevents the ERG death spiral if you lose power • Lock the target manually to ride fixed watts whenever you want TRACKS YOUR PROGRESS Power at target…