Strength, kept honest.
A workout log for serious lifters, built for iPhone. I made all of it: the idea, the brand, the design system, and the product decisions behind every screen.
I ran Notch on two diamonds. First I made sure I was solving the right problem. Then I made sure I built it right.
Strength logging is a crowded shelf, and almost every app on it runs on the same engine: streaks, badges, a feed. So before designing anything, I sat down with four serious lifters. The same answers kept coming back. They already track their training. They judge a set by the reps they had left in the tank, not just the weight on the bar. And every app they'd tried buried that under gamification. I'm one of them, which helped me hear the thing nobody said out loud: a serious lifter already knows whether they showed up. Turning up isn't the question.
4 interviews — the answers that kept coming back
Andrei — the persona the four interviews produced. The lifter every screen answers to.
So the problem wasn't motivation, and it wasn't more data. It was proof: a lifter can't easily see whether the work is working. That gave me the line I designed everything against — strength, kept honest. Two decisions locked here and never moved. Reps-in-reserve sits at the centre of every logged set, so the app knows how hard each set felt. And strength over time is shown honestly, so an easy day is never dressed up as progress.
The waist of the first diamond
Strength, kept honest.
With the problem fixed, the open question was how to show progress without lying about it. I explored a few readings of the same training data: an honest max estimate adjusted for effort, so a lucky day doesn't read as a gain; stall detection that watches the trend, not one bad session; muscle balance and personal records by rep range. I didn't decide alone — once early users were in the private beta, a feature survey ranked what got built, and the winners became the progress screens.
The brand grew in this diamond too. A ram's horn adds a ring for every year it lives, and training adds a notch every session. That gave me The Keeper, the ram, and a notched horn for the mark, wrapped in Dark Ledger: warm near-black, monospace numerals, quiet PRs with no confetti, nothing on screen unless it means something. Then the part that proved the definition was real. I built a streak counter, liked it, and killed it, because a streak is the exact game Notch exists to end. Deleting it sent me back to check the one-line problem still held. It did.
Converging was mostly subtraction. The exercise library went from 873 to 438, keeping the lifts a serious program actually uses, and features I was excited about moved to after launch. I designed every screen and directed AI dev tools through the build, so the design lives in the code and nothing dies in a hand-off. What I'll watch after launch isn't installs. It's whether lifters keep coming back because the app told them the truth.
Where it honestly stands
The diamonds didn't run in a straight line. They never do. The streak counter was the loop that mattered: the solution argued with the definition, and the definition won.
Next — 02 From catalogue to funnel. →


