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Fitness, Fatigue and Form

Last reviewed October 14, 2026 View as Markdown

YOUB turns the Load Scores of your activities into three curves. Fitness base is your long-term training load, averaged over about 42 days. Recent load is your short-term training load, averaged over about a week. Freshness is Fitness base minus Recent load: positive when you are rested relative to your fitness, negative when recent training outweighs it. The curves appear once you have seven days with a training load, and they continue into the future as a forecast built from the sessions in your plan. How a single activity gets its Load Score is explained in How YOUB Calculates Training Load.

App Names and Common Terms

The three metrics have different names in other training tools. In the YOUB app they are called:

In the app Also known as
Fitness base Fitness, CTL (Chronic Training Load)
Recent load Fatigue, ATL (Acute Training Load)
Freshness Form, TSB (Training Stress Balance)

The coach understands both sets of names, so you can ask about "CTL" or "Fitness base" alike.

Where to Find Fitness, Fatigue and Form

The metrics live in the Training status bar at the top of the home screen, which shows your current Fitness base at a glance. Opening it shows Fitness base, Recent load and Freshness, a Fitness & load chart, a Freshness chart, your Weekly distance, this week's plan progress and the latest adaptation the coach made to your plan. In the expanded view you can move along the chart to see the values for a specific day.

Fitness Base (CTL)

Fitness base is your long-term training base. YOUB calculates it as a weighted average of your daily Load Scores over roughly the last 42 days, in which recent days count a little more than older ones. Fitness base rises slowly through weeks of consistent training and decays gradually when you train less or rest. A higher Fitness base means your body is used to handling more training.

Recent Load (ATL)

Recent load is your short-term training load. YOUB calculates it the same way as Fitness base, but over roughly the last seven days, so Recent load reacts quickly: a hard training block lifts it within days, and a few easy or rest days bring it back down.

Freshness (TSB)

Freshness is the balance between the two: Fitness base minus Recent load.

  • Positive Freshness means your recent training is lighter than your long-term base. You are rested relative to your fitness.
  • Negative Freshness means your recent training is heavier than your long-term base. You are carrying fatigue from building fitness.
  • Freshness near zero means your recent training matches your long-term base.

How to Read the Numbers

The direction of the curves says more than any single value:

  • Rising Fitness base with moderately negative Freshness is the typical picture of a productive training block.
  • Deeply negative Freshness that keeps falling means fatigue is piling up faster than your base grows. Easier days or a rest day let your body absorb the work.
  • Freshness turning positive after a lighter phase is what a taper before a race aims for: your base stays high while the fatigue drops.
  • Rest days lower both Fitness base and Recent load, Recent load much faster. A rest day lets your body absorb the training you have already done.

What counts as "deeply negative" differs between athletes and depends on your Fitness base, so compare your Freshness with your own history rather than with someone else's. The coach can read the curves with you and explain them in the context of your plan.

Which Activities Count

Only activities with a Load Score feed the three curves. An activity without one (for example a session with no power, pace or heart rate data, or a sport that is analysed without a Load Score) still appears in your training log and weekly totals, but it does not move Fitness base, Recent load or Freshness. When the same workout arrives from more than one connected app, YOUB counts it once. All activities of a day are added up into that day's load.

When the Fitness Chart Appears

Fitness base, Recent load and Freshness appear once you have at least seven days with a training load. With less data the numbers would be misleadingly low. When the seventh day arrives, YOUB starts the curves from the average daily load of those first days, so they begin at a realistic level instead of climbing up from zero. YOUB looks back about six months to build the curves. Until the chart appears, your activities are still shown in the app; only the long-term load curves are hidden.

Fitness Forecast

The Fitness chart continues past today as a forecast. YOUB takes your current Fitness base and Recent load and projects them forward day by day using the planned Load Scores of the sessions in your plan (how planned load is computed is described in How YOUB Calculates Training Load). Days without planned sessions count as rest days. A planned session YOUB cannot put a load on, such as a swim session, stays on your plan but counts as zero load in the forecast.

The forecast lets you:

  • See whether your plan builds Fitness base at a sustainable rate.
  • Check that Freshness will be positive on the day of a target race.
  • See how Freshness is projected to change through a hard block or a taper.

Trying Different Scenarios

To try a different scenario, such as an extra rest day or a bigger week, ask the coach in the chat. The coach reads the projected Fitness base, Recent load and Freshness of your current plan, can change the plan accordingly, and the forecast then follows the changed sessions.