Hey,
I need some more exact information to better understand what sort of app you're looking for.
1. Is it going to be used only by you, or do I need to set up a server to handle multiple users and their data?
2. Is it a Windows (.exe? .py?) app or a mobile(Android?) app? Or would you like to use it from a website instead?
3. What features to include: What kind of exercises you'd like, whether you'd like for it to automatically update a Sheet with progress details, etc.