TSB
training stress balance, freshness
The difference between fitness and fatigue (CTL minus ATL) — an indicator of how rested you are today.
Positive TSB means fatigue has dropped below your fitness level — you are rested. Negative means fatigue dominates, which is normal mid-block and undesirable on race day.
That is what a taper is: you stop adding load, fatigue (ATL, a 7-day average) falls fast while fitness (CTL, a 42-day average) falls slowly. The gap opens and you arrive fresh with almost no loss of preparation.
Trenaio shows a TSB forecast for race day, derived from the load of your planned sessions. It answers “will this plan get me there rested”, not “what time will I run”.
How to read the values
What to do about it
- Do not try to hold positive TSB all season — without periods of fatigue there is no adaptation.
- Plan the taper so the race-day forecast lands between +5 and +25.
- If TSB has been strongly positive for weeks, you are probably undertraining rather than resting wisely.
A common misconception
“I will race best at maximum TSB.”
Past a point, freshness stops helping and starts hurting: too much rest leaves you flat and out of touch with race pace. That is why race week keeps short efforts at goal pace.
Related terms
See these numbers on your own data
In the app every indicator comes with an explanation of what it means in your case and what we suggest doing next.
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