How the difficulty bands are calculated

While you build a workout, each station carries a target time for three levels: Beginner, Advanced and Elite. There is one idea underneath all of it. Every station reduces to an amount of work and a rate, and a band is just a rate. Multiply the work by the rate and you have a time; the three bands give you three times.

Work comes in three currencies, so there are three rates. Repetitions are priced in seconds per rep, calories in seconds per calorie, and distance in seconds per metre. Beginner is 3.0 seconds per rep, 5.8 per calorie and 0.45 per metre. Advanced is 2.4, 4.3 and 0.316. Elite is 2.0, 3.7 and 0.259. Lower is faster, so a lower number is the harder band.

Those decimals are easier to judge in familiar units. On the rep rate the bands work out at 20, 25 and 30 repetitions a minute. On calories, roughly 10, 14 and 16 a minute. The distance rate is a running pace: multiply by a thousand and Beginner is 7:30 per kilometre, Advanced 5:16, Elite 4:19. If those paces look like the right shape for the three levels, the model is doing what it should.

A station with a fixed amount of work runs the arithmetic forwards. Twenty wall balls at 3.0, 2.4 and 2.0 seconds a rep is 60, 48 and 40 seconds. A five hundred metre row at 0.45, 0.316 and 0.259 is 3:45, 2:38 and 2:10.

A timed station runs it backwards, and this is the more useful direction. You have fixed the window, so the question is how much work fits inside it. Sixty seconds of rowing is 133 metres at Beginner, 190 at Advanced, 232 at Elite. That is why a timed station shows a distance, a rep count or a calorie count rather than a time: the time is already decided, and the target is what you are being asked to produce within it.

The workout style changes the question again. An AMRAP has a cap, so the band is expressed as rounds completed inside it. An EMOM asks something simpler and more brutal: at this rate, does the work fit in the minute at all? A station that takes fifty seconds at Elite and seventy at Beginner is an EMOM for one of them and a treadmill of accumulating debt for the other.

The rates are served from a file rather than compiled into the app, so a number that turns out to be wrong can be corrected for everyone without an App Store release. The app ships with the same values built in and falls back to them if the file is missing, malformed, or has a band out of order — the estimates are never left broken by a bad edit, they simply stop changing.

Two honest limits. The rate is the same for every exercise in a currency, so a burpee and a wall ball are priced identically per rep, which is plainly not true of how they feel; the model is calibrated for pacing a session, not for ranking movements. And a band is a pace, not a verdict. Finishing a workout at the Advanced line means you moved at that rate on that day, which is a useful thing to know and a poor thing to take personally.