Pick what you want a trainer session to do: burn calories, or build Zone 2, threshold, V̇O₂max, or anaerobic work. The Workout Builder finds the workout that gives you the most of it that you can still finish, either from published protocols or optimized for you. Edit it, then export for Zwift, Garmin, ERG/MRC, or Intervals.icu. It runs right here on the site, with nothing to install and no sign-in.
These are real workouts, and the hard ones are very hard. If you're new to high-intensity training, coming back from time off, or managing a health condition, check with your doctor before you ride one.
Models & references are listed inside the app.
Enter your FTP and body mass, choose what you want the session to do, and the Workout Builder ranks every workout structure that fits that goal, then builds the version that delivers the most of it while you can still finish. You don't need an account, and there's nothing to download.
As Researched runs published protocols, scaled to your FTP: Seiler 4×8 and 4×16, Helgerud 4×4, Billat 30/30, Rønnestad 30/15 and fast-start intervals, Tabata 20/10, Gibala sprint intervals, and the Norwegian AM/PM threshold sessions. AI Optimized searches each structure's reps, sets, durations, intensities, and recoveries for the cheapest version that hits your chosen difficulty, from Breezy to Brutal.
Every workout is simulated second by second with a critical power and W′ model: W′ refills in two phases (Chorley 2023), critical power fades with accumulated work (durability), and a completability check rejects sessions no one could finish. Calories come from V̇O₂ kinetics and the Weir equation; the substrate split from the respiratory exchange ratio. Every model choice and study is listed inside the app.
Fine-tune any step in the editor, then download the workout for Zwift (.zwo), Garmin and other head units (.fit), ERG and MRC trainer files, or as Intervals.icu workout text. Targets are written as % of FTP (ERG in watts), so they scale to your numbers.