That is precisely the kind of record that is useful to have and uncomfortable to hand over, and the usual argument for sending it away — that the maths needs a server — has not been true for years. Exponentially weighted averages of daily load, an RMSSD scored against a rolling baseline, a 1RM fitted from your own load–velocity line: all of it runs comfortably on a phone.
cronoWiz computes it there. Fitness, fatigue and form on the Banister model, a readiness state, heart-rate zones, tonnage by muscle group, best efforts by duration. The numbers come from your sessions and stay with them, and the app explains which model produced each one instead of rounding everything into a single score.
Nothing is uploaded because there is nowhere to upload it to. When you want the data elsewhere, you move it deliberately: an encrypted file, or a direct transfer to another device.
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The maths runs on the phone
load, readiness, zones and estimates are computed locally from your own sessions.
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HRV without a subscription
measured from the camera in sixty seconds, or read from a Polar H10 as RR intervals.
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Every number has a source
the model behind each figure is named, not hidden behind a colour.
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Export on purpose
an encrypted .cwbackup, or peer-to-peer transfer. No background sync.
Free. Private. Yours.
No account. No server. No cookies. Just you, your phone, and an app that minds its own business. cronoWiz is a free PWA that runs entirely on your device — your data never leaves. Ever.
The questions people actually ask
Can I still see long-term trends without a cloud?
Yes — the history lives on the device and the trends are computed from it. For a year of data on a large screen there is cw·dashboard, which reads a backup in the browser and is equally serverless.
How is HRV measured?
Either by putting a finger on the rear camera with the flash on for sixty seconds, or by reading RR intervals from a Polar H10. Camera measurement needs the torch, which iOS does not expose, so on iPhone the strap is the route.
Does it work with my watch?
Sessions recorded elsewhere can be brought in as .fit files through cw·dashboard, so they land in the same history as the ones cronoWiz recorded.