Your training stays on your phone
There is no account, no server and no sync. Everything you log is stored on this device and sent nowhere, which is why nothing here ever asks who you are, and why it all keeps working with the signal off.
The cost of that is worth saying plainly rather than burying: clear your browser data and it is gone. Back up data writes every session, setting, routine and supplement to one file, and that file is the only other copy that exists — unless you ask for one in your own Google Drive, which is a button you press, not a sync running behind you.