Fitness
CTLThe slow average of your daily load. Months of base and build raise it; it barely moves week to week.
58Today
57Race day
CTL, ATL and TSB explained: fitness, fatigue and form.
Three numbers from the Performance Manager model of Allen, Coggan & McGregor, computed from your own rides: what each means, where the load comes from, and how form brings you to your event.
iOS 26+ · iPhone · Free
Three numbers, in plain words.
All three come from the same daily load, your TSS, averaged over two different spans.
Performance Management ChartIn-app view
Race day
CTL
ATL
TSB
TSS
Where you sit
Fatigue
ATLThe fast average of the same load. It climbs with every hard block and clears within days of easing off.
78Today
44Race day
Form
TSBFitness minus fatigue: how much of your fitness you can use today. Negative in a heavy block, positive when you arrive fresh.
−20Today
+13Race day
Where the load comes from.
-
A ride comes in
From Strava or a Hammerhead Karoo, the only two sources of rides.
-
Its TSS is computed
From power when the ride has it. Without a power meter, from heart rate against your LTHR (hrTSS), so the ride still counts.
-
The model rolls forward
Fitness, fatigue and form update from each day’s TSS with the standard Performance Manager maths.
One honest limit: on long rides, heart-rate load reads high, because cardiac drift raises heart rate at the same work (Coyle & González-Alonso, 2001).
How form brings you to your event.
On Elite, the plan works backwards from your race date and steers form on purpose.
- The season
- Every week gets a phase, a fitness trajectory and a band for form, worked back from your event date.
- Peak
- One or two weeks before the taper, sized by the length of the event. Issurin (2010).
- Taper
- Fatigue falls faster than fitness, so form rises into the race. One week or two, sized by the fatigue you built. Bosquet et al. (2007), Mujika & Padilla (2003).
- Day to day
- On a good reading, a one-off dip in recovery only softens the session when form confirms the fatigue.
In the app.
Pro measures it. Elite acts on it.
| In the app | Plan |
|---|---|
| Rides imported from Strava or a Hammerhead Karoo | Free |
| Fitness, fatigue and form (CTL, ATL, TSB) | Pro |
| Detailed ride analysis, eFTP, W′bal, the power curve and the effort calculator | Pro |
| Notifications for a new eFTP and for peak form | Pro |
| Today’s session, cut from the week’s load budget | Elite |
| Periodisation, peak and taper to your event | Elite |
Riding by heart rate? The Training tab shows the PMC built from your heart rate; eFTP, W′ and the power curve need power data. Prices, with the storefront and VAT caveat, are on the pricing page →
Questions before you start.
Do I need a power meter for CTL, ATL and TSB?
No. A ride without power still counts: its load is computed from heart rate, and a heart-rate rider's Training tab shows the PMC built from it. eFTP, critical power, W′ and the power curve do need power data. Since app 1.7.0 every structured session can also be ridden by heart rate; the full session, in watts or in heart rate, is Elite.
Is Summit's CTL the same number other apps show?
It is the same Performance Manager model and the same maths, applied to your own rides, so it compares with any tool built on that model. Summit does not claim a better CTL, only a better use of it.
Can I see my form without the plan?
Yes. Fitness, fatigue and form are Pro, with the ride analysis, eFTP, W′bal, the power curve and the effort calculator. Elite adds the plan that acts on them: the session, the periodisation and the taper to your event.
What happens to my load if I miss a session?
On Elite, the week keeps its load. What you missed is spread across the days still open, and a missed key session moves to a later training day of the same week. One miss re-plans this week and the next, not your season.
Is the load model AI?
No model decides anything. Fitness, fatigue and form are computed from your own TSS with the Performance Manager model of Allen, Coggan & McGregor, which the app cites with the rest of its sources. How Summit combines its models is not published, but every number traces back to a rule.
Keep reading.
- Taper and peak: reading your TSB to arrive in form
- Structure your season: base, build, peak
- Cycling recovery: what Summit reads overnight
- How the adaptive plan uses your recovery and your week
- Every integration, and what is not integrated
- Summit vs TrainingPeaks: the dashboard and the decision
- Plans and pricing, with the caveat
Bring your rides in.
Download Summit and connect Strava or your Hammerhead Karoo. Fitness, fatigue and form are Pro, the plan built on them is Elite, and your recovery score and sleep readings are free.
iOS 26+ · iPhone · Free