Power and Cadence vs. Speed.

This page uploads a TCX file and plots power in Watts and cadence vs. speed. It fits a line to the data as the relationship between cadence vs. speed and power vs. speed is approximately linear. The resulting two coefficients may then be used with my Garmin Connect IQ field for the track.

It should be used from data obtained at various running speeds on a track for the correlation to be valid. An R² of more than 0.6 indicates a reasonable dataset for the correlation. If less than 0.6 you probably need to get a more varied running session on the track with efforts in a variety of pace/power zones.