Rhythm watches your own log for one sign: a lift that has stayed flat for several sessions.
Rhythm works out an estimated one-rep max for each lift from the weight and reps you record, and when three sessions in a row land inside the same narrow band — within about 2.5% of each other — it calls that flat. It waits until you have at least twelve logged sessions before it uses the word at all, because three sessions out of five is noise, not a pattern.
A lift without a usable estimate gets a simpler test: did the weight or the reps go up? Three sessions with neither, or four sessions without more reps on a bodyweight move, counts as flat. If you did more work around the top set, such as an extra set, Rhythm does not call the lift flat.
When a lift is flat, Rhythm offers one next step and rotates through them: a different rep range, a pause at the bottom, about 10% off the weight for a week, a variation of the lift, an extra set, or about half the sets at the same weights. It is an offer, not an order.
Coaches also watch effort creeping up at the same weight, where the set that used to leave you two reps short now leaves you none. Rhythm does not track it. Logging reps in reserve is not in the app today, so plateaus are read from the weight and reps you record instead. We would rather tell you that than let the picture look complete when it is not.
No study fixes three sessions, or 2.5%. We looked, and found no peer-reviewed rule for spotting a stall from logged sets alone. Those thresholds are our judgement, set slow enough to ride out normal week-to-week noise, and what would prove them wrong is simple: if they call a deload for people who did not need one, or stay quiet while people stall, they are wrong and we will change them.
An easier week is still a training week. A walk, some mobility, a lighter session on the same lift — all of it counts.