trace is now on the iPhone
Training doesn't happen at a desk. The most important answers from trace are now where they're needed: on your iPhone.
When I wrote down the story of trace, trace was a web platform. The most important building block since then fits in your pocket: trace is now available as an iPhone app, on the App Store as „trace: Cycling & Running". A deep read of your training and health data, a plan that adapts to your everyday life, and a coach you can ask anything: what used to take several apps and a trainer now sits in one app.
Why an app?
Training doesn't happen at a desk. The question „How recovered am I today?" comes up over morning coffee, the question „Was that too hard?" right after the session. The app is built exactly for those moments.
What the app computes
- Readiness: every morning a value from 0 to 100 built from sleep, HRV, resting heart rate and training load, with every factor behind it, each measured against your own values from recent weeks instead of population norms.
- Training load: fitness, fatigue and form (CTL, ATL, TSB), plus warnings when your build gets too steep or your training too monotonous.
- The full analysis: Critical Power and W' from your normal rides, no test protocol, plus power curve, W'bal and rider type, fatigue resistance, aerobic efficiency, VO2max and fitness age, heat acclimatization and automatically detected climbs with VAM and pacing. For running: Critical Pace, heart-rate recovery and training effect.
- Plans all the way to your device: training plans with structured sessions that react to your actual training and land directly on your Wahoo, Suunto or Hammerhead device or the Apple Watch. After every session, the workout report: plan versus execution.
- Race prep and nutrition: course simulation, race prognosis and pacing for your target race, plus carbohydrate and fluid amounts in grams and milliliters, for training and for race day.
- The trace Coach in your pocket: ask right in the app why your readiness is low today or whether the last session was too hard. The coach knows your entire training history and your goals.
One point that matters to me: all of these values are computed, no language model is involved. The AI sits on top. It explains your values, answers questions, writes the report after the session and drafts the training and nutrition plans, and even there it stays inside computed limits: periodization, weekly TSS and fueling targets come from the engine, and every generated week is checked against them.
How your data gets in
Apple Health (iPhone and Apple Watch), Wahoo, Polar, Suunto and Hammerhead connect directly, and you can import FIT, TCX and GPX files. Garmin and Strava come in via intervals.icu, which trace reads out completely: activities, streams and health data. Once connected, new sessions land in trace automatically.
Web and app, one account
The app doesn't replace the web, both work on the same account and the same data. In practice it settles quickly: the morning glance, the pre-session briefing and the coach happen on the iPhone, the long weekend deep-dive on usetrace.de on the big screen. In the browser, trace runs on any device, and a native Android app is in the works.
What it costs
The base version is free for good. The full analysis is Athlete at €6.99 per month, training plans, race prep and the coach in full are Pro at €12.99, each 20 % cheaper yearly and both free to try for 14 days. On top of that, the first two weeks of every training plan are completely free, device push included. Your data: hosted in the EU, full export any time, no ads.
You'll find all the details and the App Store link on the app page. Feedback and suggestions are welcome any time: that's exactly where every good feature has come from so far.