Power TSS in Enduroco

When a cycling activity has usable watts data and FTP, Enduroco computes load from the power stream and sets source to Power stream (NP/IF, 30s) (cycling.powerTss).

Inputs Required

• Cycling activity type (Ride, VirtualRide, or EBikeRide)
• FTP (thresholds.cycling.ftp)
• Watts stream (raw or persisted)

Calculation Steps

1. Compute a rolling average over 30s power windows.
2. Raise each rolling value to the 4th power.
3. Average those 4th-power values.
4. Take the 4th root to get Normalized Power (NP).
5. Compute Intensity Factor (IF): IF = NP / FTP.
6. Compute TSS:

TSS = (duration_seconds * NP * IF) / (FTP * 3600) * 100

Equivalent form:

TSS = (duration_seconds * IF^2 * 100) / 3600

Practical Read

• 1 hour at IF = 1.0 gives about 100 TSS.
• Same duration at lower IF gives proportionally lower load because IF is squared.

Notes

• Enduroco stores computed power metrics (normalizedPower, intensityFactor, tssExact, tss) and recalculates against current FTP when needed.
• If power-stream TSS is available, it becomes the canonical cycling load source.

References

• TrainingPeaks: Normalized Power, Intensity Factor, and Training Stress Score
• TrainingPeaks Help: TSS