How to Read Your Performance Management Chart (Without a Sports Science Degree)

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If you've opened the Performance tab in HARDN and seen three lines moving in different directions with acronyms underneath, you're not alone. CTL, ATL, TSB — it looks like a stock chart someone drew while exhausted. Which, honestly, is appropriate.

Here's what it actually means and why it's the most useful thing on the platform.

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## The three numbers

### CTL — Chronic Training Load

This is your fitness. Specifically, it's a 42-day rolling average of your training stress. The longer you train consistently, the higher this number climbs. Think of it as the accumulated result of months of work — the engine you've been building.

CTL moves slowly. You can't spike it in a week and you can't lose it overnight. It's the most honest number on the chart.

### ATL — Acute Training Load

This is your fatigue. It's a 7-day rolling average of your training stress — what you've done recently. A big weekend of back-to-back long runs sends ATL climbing fast. A rest week brings it down just as quickly.

ATL is reactive. It tells you what your body is dealing with right now.

### TSB — Training Stress Balance

This is your form. It's the difference between your fitness and your fatigue — CTL minus ATL.

When TSB is negative, you're carrying more fatigue than your fitness base can absorb. You're tired. When TSB is positive, fatigue has dropped below your fitness level. You're fresh. You're ready.

The goal of a training plan is to build CTL over time while managing ATL — and to arrive at your race with TSB in the right range.

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## What the chart should look like

During a hard training block, ATL runs above CTL. You're accumulating fatigue faster than your long-term fitness is rising. TSB goes negative. This is normal. This is the work.

During a taper, you back off volume. ATL drops. CTL holds or dips slightly. TSB climbs toward positive. Your legs come back. The fitness you built over months becomes available again.

On race day, you want TSB somewhere between +5 and +25. Fresh enough to perform. Not so rested that you've lost your edge.

If TSB is -25 on race morning, you went into the taper too tired or didn't taper long enough. If TSB is +35, you backed off too early and left fitness on the table.

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## How HARDN uses it

Your HARDN Score pulls directly from this data. Freshness is one of the seven factors — your TSB trend over the past week affects your readiness score every single day.

The AI Coach sees your CTL, ATL, and TSB before it says anything to you. When it tells you to back off today's workout or push the tempo session, it's not guessing. It's looking at whether you're digging a deeper hole or whether you have room to absorb more stress.

The daily athlete state — the thing that drives workout adjustments, nutrition targets, and recovery recommendations — is built on these same numbers. Every feature in HARDN that adapts to you is downstream of this chart.

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## What good numbers look like

There's no universal target. But here are rough benchmarks for ultra runners:

- CTL 30–50: Building base. You're training consistently but still early in a block.
- CTL 50–70: Solid foundation. You can handle a 50K comfortably.
- CTL 70–90: Strong ultra fitness. 100-mile territory.
- CTL 90+: Elite-level load. Sustainable only with years of base.

For TSB on race day:
- +5 to +15: Ideal for most athletes. Fresh but sharp.
- +15 to +25: Very fresh. Good for a first 100 where you want extra margin.
- 0 or below: You're not tapered. Consider adjusting.

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## The one thing most people get wrong

They look at TSB going negative during training and panic. They think something is wrong. They back off too early.

Negative TSB during a training block is the point. You're supposed to be tired. You're building fitness. The fatigue is temporary — the CTL gains are permanent (as long as you stay consistent).

The art is knowing when negative TSB is productive overreach and when it's digging a hole you can't climb out of. HARDN flags this for you. If your TSB drops below -20, you'll see it in your daily state and the AI Coach will mention it.

Trust the process. Watch the chart. Taper when it's time.

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Open the Performance tab in HARDN to see your live CTL, ATL, and TSB. The chart updates daily as you log workouts.

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HARDN is built for athletes who take this seriously. Track your training, your race execution, and your progress — all in one place. [Start for free →](https://hardn.app)