Cosmos: what is shared and what is not
Box by box, and what never leaves even if you tick everything.

Your star name
Cosmos does not use your name or your email: it uses a star name generated for you (and you can ask for another). It is the only thing other people see, and it is what goes in your public page's address.
What you tick is what is shared
«My public profile» has one box per thing: rank and power, workouts, records, runes, measurements, programs. Each one says exactly what would be visible if you turn it on. Everything starts off except the minimum, and it can be turned off at any time: the page updates within a minute.
What never leaves
Your email, your real name, the notes you write on workouts and exercises, and your bodyweight unless you ticked it. Those have no box because there is no way to turn them on.

Challenges and the leaderboard
Collective challenges add everyone's contributions towards a shared target, and the leaderboard is optional: if you do not want to appear, you do not. Neither needs you to share your workouts.
More on How the app works
The first five minutes
Pick a plan, train, see what happens at the end. That is all.
Inside the workout screen
The one you will use most, and the one hiding the most.
Routines, programs and other people
What each one is, where they come from, what sharing actually sends.
What each chart is looking at
Progress has six things and each answers a different question.
Your data: cloud, backups and importing
Where your history lives, how to get it out, how to bring it in.
This is general information written from the training literature, not medical advice or a personalised plan. If you take medication, have a health condition or something genuinely hurts, the person to ask is a healthcare professional.