Marafit: Marathon Training

Your half and full marathon plan, rebuilt from what you actually ran. Paces from your own efforts, not a formula. Everything computed on your iPhone — nothing uploaded.

Marafit turns your own Apple Health running data into a full 16-week marathon plan — and keeps adjusting it to what you actually run.

Most training apps hand you a template and ask you to fit into it. Marafit reads your last 90 days of runs, works out your heart-rate zones, your easy pace, your threshold pace and your current fitness, and builds the plan around those.

WHAT YOU GET FOR FREE

• A complete 16-week periodised plan — 3:1 build/down weeks, a 3-week taper, every session placed on a real date • Pick your own training days: long run day, quality day, and as many support runs as you want (3 to 6 sessions a week) • Personal heart-rate zones for every session, derived from your maximum and resting heart rate via the Karvonen method • Daily readiness score from HRV, resting heart rate and sleep, with the full breakdown of how it was calculated • Today's fitness, fatigue and form (CTL / ATL / TSB) • Weekly score: planned versus actual, session by session • Long-run comparison: heart-rate curve and time in each zone • A realism check on your goal time, so you find out before week one rather than on race day

MARAFIT PRO

• Paces tuned to you — easy and threshold paces come from your own measured efforts and VDOT, instead of being derived from your goal time • A plan that follows you — miss a week or overshoot one, and the remaining weeks are re-anchored to what you actually ran • Fitness and fatigue trends over 90 days, not just today's numbers • Deep run analysis — aerobic efficiency, heart-rate drift with warm-up removed, heat stress from the temperature and humidity recorded during the run, plus running dynamics and elevation

HOW IT WORKS

Marafit reads runs, heart rate, HRV, resting heart rate, VO2 max, sleep and body metrics from Apple Health. It never writes anything back. Every calculation runs on your iPhone.

The training model follows established methods: Karvonen heart-rate reserve for zones, Daniels VDOT for equivalent performances and threshold pace, Banister TRIMP for training load, and the CTL / ATL / TSB fitness-fatigue model.

BEFORE YOU START

Marafit needs running history in Apple Health to build anything — record runs with Apple Watch or the iPhone Workout app. If you have none yet, tap "Or explore with demo data" on the first screen to load 13 weeks of sample runs and see the whole app, then clear them in one tap.

Currently supports the full marathon (42.195 km). Half marathon is not included: the periodisation, long-run progression and race-pace work are all calibrated for the full distance, and offering a rescaled version would produce a plan that looks usable but isn't.

iPhone only. There is no iCloud sync, so your data stays on the device you use.

PRIVACY

No account. No servers. No analytics, advertising or tracking SDKs. Your health data never leaves your device — we have no way to receive it even if we wanted to. Deleting the app deletes everything.

SUBSCRIPTION

Marafit Pro is available as a monthly or yearly auto-renewing subscription, or a one-time lifetime unlock. Eligible Apple IDs get a 7-day free trial on the yearly plan. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period; manage or cancel any time in your App Store account settings. The lifetime option does not renew.

Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/

Privacy Policy: https://jakepyth.github.io/marafit-support/privacy.html

Marafit gives training guidance, not medical advice. It does not diagnose or treat any condition. Consult a physician before starting a new training programme, and stop if you feel unwell.