Norwegian 4×4 Cycling

Heart-Rate ERG Trainer

$3.99 · Designed for iPad. Not verified for macOS.

Watts follow your heart rate, not a fixed number — so every 4×4 interval lands in the 90–95% HRmax zone whether you're fresh or tired. No guessing. 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 HR is the headline metric. Each session, the app asks: how many watts did it take to hold 90–95% HRmax? That number, plotted over weeks, shows whether you're getting fitter. The app builds a rolling 8-session trend once four sessions are logged. Sessions with poor HR-band adherence are excluded automatically. No streaks, no badges — just the number. HEALTHKIT INTEGRATION Sessions save to Apple Health as indoor cycling workouts with full HR sample data. VO₂max, resting heart rate, and body mass are read at session start to calibrate targets. No account required. No cloud. Your data stays on your device. HARDWARE COMPATIBILITY Works with any Bluetooth smart trainer. Confirmed working with Jetblack and Wahoo. Heart rate via your trainer's built-in HR bridge or any BLE heart rate sensor. ONE-TIME PURCHASE. NO SUBSCRIPTION.

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Redesigned device pairing: manage your trainer and heart rate sensor in one place, and switch between remembered devices with a tap.

Version 1.0.2

The developer, Jerome Soika, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary, for example, based on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Seller
    Jerome Soika
    Size
    2 MB
    Category
    Sports
    Compatibility
    Requires iOS 17.0 or later.
    • iPhone
      Requires iOS 17.0 or later.
    • iPad
      Requires iPadOS 17.0 or later.
    • Mac
      Requires macOS 14.0 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 1.0 or later.
    Languages
    English and 12 more
    • English, Danish, Dutch, Finnish, French, German, Italian, Japanese, Norwegian Bokmål, Polish, Portuguese, Spanish, Swedish
    Age Rating
    9+
    Copyright
    © 2026 Jerome Soika
  • Developer Website
  • Privacy Policy

    • Supports

    • Family Sharing

      Up to six family members can use this app with Family Sharing enabled.

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