Chronic Training Load (CTL) represents your fitness level as a rolling average of daily TSS over approximately 42 days. Higher CTL means greater training adaptation.

Acute Training Load (ATL) represents your recent fatigue as a rolling average of daily TSS over approximately 7 days. High ATL means you are accumulating fatigue.

Training Stress Balance (TSB) = CTL - ATL. Positive TSB means you are fresh (rested). Negative TSB means you are fatigued. Ideal race form is typically TSB of +15 to +25.

What CTL should I target?

Recreational: 30-50. Club racer: 60-80. Competitive amateur: 80-110. Professional: 100-150+. Build CTL by no more than 5-7 points per week.

BikeCalcs

Training Load Calculator — CTL, ATL & TSB

Estimate your fitness (CTL), fatigue (ATL) and form (TSB) from training data.

Average Weekly TSS

Your typical weekly total TSS

Weeks at This Load

Today's TSS

TSS from today's ride

How We Calculate This

Performance Management Chart

The PMC model uses exponentially weighted moving averages:

CTL (Fitness) = 42-day exponential moving average of daily TSS
ATL (Fatigue) = 7-day exponential moving average of daily TSS
TSB (Form) = CTL - ATL

This simplified calculator estimates CTL from your average weekly TSS and estimates ATL based on today's session.

Frequently Asked Questions

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Last updated: 2025-02-20

All calculations are estimates. Always verify results and consult a professional bike fitter where appropriate.