Power Intensity

Power Intensity expresses Weighted Power relative to the applicable power threshold.

Formula

Power Intensity (PI) = Weighted Power / effective FTP

Both inputs are watts, so PI is dimensionless. The threshold resolver distinguishes cycling, explicitly configured indoor cycling FTP and running threshold power. It uses the applicable dated setting. PI is not the percent of time spent in a zone or average power divided by FTP.

Verified example

Weighted Power 200 W and FTP 250 W produce PI 0.80, equivalent to 80% of that threshold. With the same 200 W and FTP 200 W, PI is 1.00. Changing the threshold changes PI even though the recording is identical.

Availability and use

The Weighted Power quality and timer rules apply. Missing or nonpositive effective FTP prevents PI; a run without its own running threshold does not borrow cycling FTP. Threshold history and recalculation can change past values. PI contributes squared to PSS. Compare similar-duration activities and the actual sensor evidence in Activity Analysis; one ratio does not capture the whole session.

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

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