The thinking behind your next workout.
Kronos is an adaptive workout app for iPhone and Android, made by Muller Labs, LLC. It exists to fit real training into the week you actually have, not the week you meant to have.
Who writes here
The people building Kronos write these guides and run this site. That means we know the product cold, and it means our app comparisons come from a competitor. We say so on every one of them. The research we cite backs specific training claims; none of it is a study of Kronos.
How a workout gets built
You tell Kronos your equipment, your time and how you feel. It assembles a session from a pool of 580 exercises, with your gear as a hard filter and your recent training as context. A program adds a weekly arc; each day inside it is still written on the day. You can swap a movement, turn the effort dial, and let the timer run the rest.
What the evidence can and cannot tell you
We link a paper wherever it shaped a training decision, and we say what the paper actually tested. A trial on short sprint intervals is evidence about short sprint intervals, not a clinical trial of this app. Training response varies. A benchmark in Kronos measures what you did; it does not promise a bigger number.
How we check a guide
Product claims are checked against the app as it ships. Comparison claims link to the other product’s own documentation and carry the date we read it. Citations name the paper and its limits. The updated date moves when the substance changes, not when we fix a typo. Translations come from the same English source, with a second model reviewing the first.
Where this stops
These guides are about general fitness and the habit of training. They do not diagnose pain, prescribe rehab or replace a coach or a doctor. Kronos records training. It does not measure body fat or promise a transformation.
Spotted something wrong?
Send the page address and the detail to Support. A wrong source, a product change we missed, an instruction that did not make sense: all of it belongs there, and we would rather hear it.