Shindo Endurance Training

Your first triathlon, on the watch you already own

iOS

Health & Fitness

Sports

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Hi PH 👋 I built Shindo because I got tired of the integration problem: my watch had a readiness score, one app had my fitness and fatigue curves, and my training plan lived in a spreadsheet that stopped resembling my life by week three. Every morning I was doing the synthesis myself, badly, at 6am. Shindo does that synthesis. It reads Apple Health — whatever device wrote the data — computes readiness with the four drivers behind it, models training load per sport, and builds the week. When you miss sessions or swap a run for a ride, it counts what you actually absorbed and re-flows the block instead of leaving you with a plan for an athlete you no longer are. The part I'd most like feedback on is the constraint I built it around: there's a language model in the app, and it is not allowed to do arithmetic. Every number is computed deterministically on-device first; the model receives finished numbers and writes sentences about them, and if its text disagrees with a computed value the computed value overwrites it. There's exactly one exception — the weekly plan, where the model may propose a week that a 19-rule validator then accepts or rejects against limits derived from your own data. If it rejects twice, you get the engine's own week and never see a failure. The whole methodology is published, constants included: https://shindo-app.com/methodology It's free for readiness, the plan, the load charts and workout detail. Pro adds the AI interpretation and the forward-looking models. Honest limits, so nobody wastes a download: iPhone only, no Android, it can't push workouts to your watch, and it doesn't record sessions — it reads what your device already recorded. If you don't own something that tracks sleep and HRV, it has nothing to work with. Happy to answer anything.