CTL, ATL, TSB Explained — the Performance Management Chart
CTL, ATL and TSB are the three core metrics of modern power-based cycling training. Together they form the Performance Management Chart (PMC) — the most important tool to visualise fitness, fatigue and current form.
What is CTL (Chronic Training Load)?
CTL stands for Chronic Training Load and measures your long-term training stress over the past 42 days. It is an exponentially weighted moving average (EWMA) of your daily TSS and represents your fitness.
The higher your CTL, the fitter you are — but a high CTL alone says nothing about how rested you currently are. Professional cyclists often have a CTL of 100–150 during the season; an ambitious amateur typically sits at 50–80.
What does my CTL value mean?
| CTL Value | Meaning | Typical Profile |
|---|---|---|
| < 30 | Low fitness level | Beginner, after a long break |
| 30–50 | Good base fitness | Regular recreational cyclist |
| 50–80 | Solid race fitness | Ambitious amateur |
| 80–110 | High fitness | Competitive racer, high volume |
| > 110 | Pro-level fitness | Professionals, elite amateurs |
What is ATL (Acute Training Load)?
ATL stands for Acute Training Load and measures the short-term training stress of the past 7 days (EWMA over 7 days). ATL represents your current fatigue — how much training your body is currently processing.
A high ATL means you have trained a lot recently and are correspondingly fatigued. This isn't bad — without stress there is no adaptation. But if ATL remains persistently higher than CTL, overtraining is a risk.
What is TSB (Training Stress Balance)?
TSB stands for Training Stress Balance and is the simplest of the three metrics: TSB = CTL − ATL. It is your current form.
A positive TSB means you are rested (fitness outweighs fatigue) — the ideal state for races or hard tests. A negative TSB indicates fatigue — typical during intensive training blocks.
Interpreting TSB values
| TSB Range | State | Recommendation |
|---|---|---|
| > +10 | Very fresh / over-recovered | Increase intensity, add volume |
| 0 to +10 | Fresh, good form | Ideal for racing or FTP test |
| −5 to 0 | Slightly fatigued | Normal during training |
| −15 to −5 | Build phase, moderate fatigue | Keep training, monitor recovery |
| < −15 | Highly fatigued | Plan a recovery week |
| < −25 | Overreaching risk | Reduce load immediately |
The Performance Management Chart (PMC)
The PMC shows CTL, ATL and TSB as curves over time. It is the central analysis tool in data-driven cycling training, developed by Andrew Coggan and Hunter Allen.
In the PMC you can see at a glance:
- How your fitness has developed across the season (CTL trend)
- When you were most fatigued (ATL peaks)
- What your form was like before races (TSB)
- Whether your tapering worked
How to use CTL, ATL, TSB in your training
Build Phase (Base & Build)
The goal is a steadily rising CTL. ATL often sits 10–20 points above CTL, TSB is negative (−5 to −20). This is normal and desired — stress creates adaptation.
Rule of thumb: increase CTL by a maximum of 5–7 points per week, otherwise injury risk increases.
Recovery Week
Every 3–4 weeks reduce volume by 40–60%. CTL drops slightly, ATL falls sharply, TSB moves positive. After the recovery week you can train harder again.
Tapering Before Races
2–3 weeks before your target event: sharply reduce volume, maintain intensity. CTL drops slightly (minimal fitness loss), ATL drops sharply, TSB rises to +5 to +15. This is the target form for competition.
PMC automatically in WattWorks
WattWorks calculates CTL, ATL and TSB automatically from your FIT files and Strava activities. The Performance Management Chart is visible directly in the dashboard — always up to date, no manual effort required.
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