The same rep family across sessions — the interval ledger. Families are what an athlete would say: 3′ @ threshold, 30″ @ vo2, 20′ @ threshold (a sustained effort is a set of one), read by DURATION for rides and runs alike so a planned 1 km rep and its execution land in one family. Per session, newest first: reps × the watts they were ridden at (or pace where the file had metres) and the % of threshold at import (of max HR in a family "… by HR": never set against watts or pace), heart rate over the first rep against the last (HR a→b — the drift, from the stream), the sRPE they gave the session, the lactate they logged, and what they wrote. THIS IS WHERE A TARGET COMES FROM: before writing watts, a pace or a % into a rep session, read interval_progression in the snapshot (the families the week ahead needs, the last three each) or this for the longer arc and every family. The same watts at a lower sRPE is the athlete getting fitter (heart rate counts only on reps of 4+ min at or below threshold; bike threshold reps: 8+ min); more watts at sRPE 9 is not a step up. Arithmetic over stored structure, nothing to cite. family is a substring of the label ("3′", "threshold"); zone filters; weeks looks back (default 12, max 52).