01 · The basics
Training load

Measure the effort of a session, not just its duration. TRIMP, acute load and chronic load.

02 · The key ratio
ACWR: acute vs chronic

The ratio between what you do this week and what your body is used to. The optimal zone, the danger zone.

03 · The risk
Spotting overtraining

Load stacking, monotony, weak signals. Why injury often shows up after a good stretch.

04 · Recovery
HRV, sleep & resting HR

What your nervous system tells you in the morning. Why we read a trend, never a single value.

05 · Multi-sport
One fatigue, many sports

Running, cycling, swimming, trail, strength: it all loads the same body. Fatigue tracked by muscle group.

06 · Honesty
Our model, its limits

What the model can do, what it approximates, and what it doesn't do. Baseload is not a medical device.

Where the model comes from

Baseload builds on tools drawn from the sports medicine and sports science literature on the load ↔ injury relationship — in particular the work on the acute-to-chronic workload ratio (Gabbett, 2016 & 2020). The core idea is simple: it's not high load that injures you, it's the too-rapid increase in load relative to what your body has learned to absorb.

These models describe population trends, not an individual prediction. Baseload uses them as a compass: to tell you when the slope is getting risky and to propose an explainable adjustment — never as a guarantee that you won't get injured.

Read this first

No model replaces how you feel or medical advice. Baseload helps you decide, it doesn't decide for you. If you have pain that persists, see a professional. Baseload is not a substitute for medical advice — see our terms of use.

Everything stays on your iPhone

Everything you'll read here is computed locally, on your device. Your health data isn't sent to a server: no raw heart rate, no GPS track, no full session ever leaves the iPhone. No mandatory account, no email, no tracking SDK. The page on the model goes into detail on this.

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