Know the workout before you start.

Eight of the app’s 44 named workouts, written out in full: the prescription, how the clock works, the published ways to scale it, and how it is scored. Read it here, run it in the app.

• Cindy · AMRAP

  Five pull-ups, ten push-ups, fifteen air squats, on repeat for 20 minutes. Score full rounds plus any extra reps. You need a pull-up bar; the scaled versions swap that requirement rather than removing it.

• Chelsea · EMOM

  Every minute for 30 minutes: the whole 5 / 10 / 15 sequence, then rest for whatever is left of the minute. One full round per minute, not one exercise per minute. It is Cindy with a stricter boss.

• Annie · For time

  Double-unders and sit-ups, 50 of each, then 40, 30, 20 and 10. You need a rope and enough floor to lie on. The app’s scaled version swaps in single-unders at the same rep counts.

• Helen · Rounds

  Three rounds of a run, kettlebell swings and pull-ups, for time. The prescribed bells are 24 kg and 16 kg; pick the version and the load you can swing with control, then keep them the same next time so the times mean something.

• Tabata · Intervals

  Eight rounds of 20 seconds on, 10 seconds off, four minutes flat. The Kronos version is air squats; the original 1996 study was brutal cycling, so the clock is Tabata and the workout is a cousin. The four minutes do not include a warmup.

• 7-Minute Workout · Intervals

  Twelve stations in order, 30 seconds of work and 10 seconds to move between them. The app runs it as 7 minutes 50 seconds before any warmup, so the name is a round number, not a stopwatch. You need a wall, a sturdy chair or step, and some floor.

• Norwegian 4x4 · Intervals

  Four running intervals of four minutes with three minutes of easy jogging between them. The reference protocol asks for 90 to 95% of maximum heart rate in the work and 60 to 70% in the recovery. Warmup and cooldown are extra, and this is a hard session, not a first run.

• The Mile · For time

  Run a measured mile and stop the clock. Kronos stores it as 1,609 meters. Same course, same conditions, every time, and the comparison is honest.

Browse all 44 workouts in the app · What is free in Kronos, and when do I need an account?