Tools · Training Load
Training load calculator
Estimate your Chronic Training Load, Acute Training Load, and Training Stress Balance from weekly TSS. Know whether you're building fitness, approaching overreach, or sitting in race-ready form.
CTL
71
Fitness
ATL
93
Fatigue
TSB
-21
Form
Productive overload
Hard training block. Progressive fitness gains — monitor recovery closely.
CTL trend: +7.1 per week (healthy build)
Watch your training load curve.
Gneta calculates CTL, ATL, and TSB from every synced workout and plots the full Performance Management Chart. Spot overreaching weeks before they turn into injuries.
How this works
The Banister impulse-response model divides training stress into two compartments:
- CTL — exponentially weighted avg daily TSS over 42 days. Proxy for fitness.
- ATL — exponentially weighted avg daily TSS over 7 days. Proxy for fatigue.
- TSB — CTL minus ATL. Positive = fresh, negative = fatigued.
This calculator uses a simplified weekly-TSS input to approximate those metrics. Your real PMC (built from daily data in Gneta) is more precise and accounts for workout-to-workout variance.
Frequently asked questions
What are CTL, ATL, and TSB?
Chronic Training Load (CTL) is your long-term fitness — the exponentially weighted average of daily TSS over 42 days. Acute Training Load (ATL) is your short-term fatigue — the same average over 7 days. Training Stress Balance (TSB = CTL − ATL) is how fresh you are right now.
What is TSS?
Training Stress Score was developed by Andrew Coggan to quantify how hard a workout was. 100 TSS ≈ one hour at threshold. Your device or training platform calculates it automatically from power (cycling) or pace + HR (running).
How should I use TSB?
TSB is your "am I fresh enough?" gauge. Positive means rested — good for racing and breakthrough workouts. Negative means fatigued — fine during a training block, risky if deeply negative for weeks. Most athletes race best with a TSB between +5 and +20.
How fast should I build CTL?
Most coaches recommend 5–8 CTL points per week during a build. More than 10 per week is aggressive and should last only 2–3 weeks. Less than 3 per week is maintenance or recovery. Ramp rate matters more than absolute CTL.
Can this replace a real training load chart?
No — this gives you a snapshot. A proper Performance Management Chart (PMC) shows CTL, ATL, and TSB over time so you can see trends, spot overreaching, and time your taper. Gneta builds that chart automatically from your Garmin data.
What if I don't have TSS values?
If your Garmin or Strava is reporting time in HR zones or a load score, those are rough equivalents. For strictly running or cycling, use Garmin's Training Load number in place of weekly TSS. It's not identical math, but the trend behavior is the same.
Keep exploring
See your whole training arc.
Connect Garmin, and Gneta graphs 90+ days of CTL, ATL, and TSB side by side with HRV and sleep.
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