Next-day Easy-load Estimate
The easy-load estimate solves the product's ATL and CTL recurrences for an equal next updated state.
Formula
Easy TRIMP = max(0, (41 × CTL − 36 × ATL) / 5)Inputs are the selected day’s current CTL and ATL. The result is a nonnegative TRIMP load estimate. It follows from solving CTL + (L−CTL)/42 = ATL + (L−ATL)/7 for the next daily update. Because labeled TSB uses previous-day values, this load would equalize the next updated averages; the zero difference appears in the following labeled TSB.
Verified example
At CTL 50 and ATL 50, the estimate is 50 TRIMP. Applying that load leaves both updated averages at 50. At CTL 50 and ATL 60, the algebra yields −22; the displayed estimate is clamped to zero. A zero estimate does not prove that any amount of rest will immediately equalize the two averages.
Limits
This is a calculation aid, not a workout prescription or a measurement of how easy a particular session will feel. It inherits TRIMP history and threshold limitations. It uses no forecast of your next day’s actual heart rate and does not substitute PSS.
Sources and implementation scope
Morton, Fitz-Clarke and Banister (1990), impulse-response performance modeling explains the research background. The formulas, windows, quality gates and examples above describe EffortSignal 0.1.13, checked September 10, 2026. Thresholds and rounding are EffortSignal rules.
Content checked September 10, 2026 · EffortSignal release 0.1.13