Training Zones and Effective Thresholds
Zones classify measured output or heart rate using the athlete settings applicable to the activity.
Boundaries and inputs
Power zone boundaries convert configured percentages to watts:
watts boundary = effective FTP × percent / 100A sample belongs to the zone whose lower bound is inclusive and upper bound is exclusive; an open-ended final zone has no upper bound. Heart-rate zones use the applicable bpm boundaries or the supported configured method. Missing or invalid settings do not create plausible-looking boundaries.
Verified example
With FTP 250 W, a power zone from 56% up to 76% spans 140 W inclusive to 190 W exclusive. A sample at exactly 190 W belongs to the next zone. An indoor-specific FTP 200 W would make the same percentages 112–152 W for a matching indoor activity. Running threshold power is resolved independently.
Time in zone and coverage
Analysis classifies usable recorded time. A distribution can report percentages of classified time while coverage separately reports how much of the recording was classifiable; these are not the same denominator. Unclassified samples must not be interpreted as recovery-zone time. The activity’s timer and gap policy depends on the displayed metric; TRIMP and Weighted Power document their load projections.
Setting changes
Effective dates and source context determine the threshold used for an activity. A new threshold is not automatically valid before its recorded date. Recalculation can change zone distributions, PI and PSS; merely reviewing eFTP does not apply it. Workout target zones use the relevant authoring settings and export conversion rules. Training Zones and Thresholds shows where to edit them.
Sources and implementation scope
Coggan, power-based training metrics provides background, not a specification of every EffortSignal rule. The formulas, windows, quality gates and examples above describe EffortSignal 0.1.13, checked September 10, 2026. Product-specific thresholds and rounding should not be attributed to the background source.
Content checked September 10, 2026 · EffortSignal release 0.1.13