I have been lifting weights for a while, and when I work out I like to use trello cards to add quick evaluations of my progress on each exercise.
Trello cards are great as they allow me to create one per exercise and then add all my comments, references etc around it.
I've been very consistent with the way I log my progress. For example, a normal entry on my barbell squat is a card comment that looks like this:
80 // (kg)
6
5
4 // tough..
So, my goal with this app is to mine all these numbers and send charts to a web app (which I will probably create in a separate project) and then run all this stuff with containers.