Get Apex free

The science

Crayons on top. Maths underneath.

Every number in Apex comes from published sports science or an open standard. Every claim here was checked against the app's code.

Why you can trust the numbers

  • Paces that fit you, not a stranger

    Your best record sets five training paces, from easy to fast repeats. Beat it and your paces move with you.

    The science: VDOT, from Daniels and Gilbert [1]

  • Fitness, fatigue and form at a glance

    Each workout feeds a slow fitness line and a fast fatigue line. The gap is your form: fresh, or carrying work.

    The science: Banister's fitness and fatigue model [2], load after Allen and Coggan [3]

  • Records hiding inside your runs

    A fast 5K in the middle of a long run still counts as your 5K record.

    The science: A sliding window over your kilometre splits. Treadmill runs don't set pace records.

  • A coach that never leaves your phone

    Answers are worked out on your iPhone, never by a cloud AI. No Apple Intelligence, no coach.

    The science: Apple's on-device Foundation Models [4]

  • Your front door stays yours

    The first and last 200 m of every route are trimmed on your phone, and routes stop at the edge of your privacy zones.

    The science: Done on the device, before anything is uploaded.

  • Your sensors just work

    Heart-rate straps, foot pods, bike sensors, power meters, trainers and treadmills pair over Bluetooth. Workouts your watch saves to Apple Health come in too.

    The science: Bluetooth standard profiles [5], read only.

  • Segments you can trust

    Race yourself, your club or your partner. Impossibly fast times and poor GPS are flagged and never ranked.

    The science: Matched on your phone within a 30 m corridor, checked again on the server.

  • Chapters you actually earned

    One chapter for each week the two of you reach your shared goal. Your minutes and theirs are added up, so either of you can carry a hard week.

    The science: The other person sees your first name and your weekly minutes in 5-minute steps. Nothing else.

  • Live sharing that switches itself off

    Only when you start it. Links stop within 6 hours, and positions are deleted a day later.

    The science: A 128-bit random link code, stored only as a one-way hash.

Built to be trusted

  • Free, all of it. No ads, no subscription, no ad trackers.
  • EU-hosted, locked down. Stored in Ireland, with row-level security on every table.
  • Your location stays yours. Never shared unless you choose to share it.
  • On-device AI. The coach runs on your iPhone.
  • Open standards. Export your runs and rides as GPX, TCX, CSV or JSON.
  • Adults only. 18+, checked by the app and the database.

What it doesn't do yet

  • No direct Garmin or Strava link. Garmin workouts come in through Apple Health.
  • No auto-pause or GPS smoothing.
  • The AI coach needs Apple Intelligence.
  • The Watch app records runs without a GPS route.
  • Live sharing sends no texts or emails. Alerts reach people in the app only.
  • iPhone only. Text doesn't grow with larger text sizes yet.

Apex is not a medical device. Want the side-by-side with other apps? See how Apex compares.

Sources

  1. Daniels J, Gilbert J. Oxygen Power: Performance Tables for Distance Runners. Tempe, Arizona; 1979. See also Daniels J. Daniels' Running Formula. 3rd edition. Human Kinetics; 2014.
  2. Banister EW, Calvert TW, Savage MV, Bach T. A systems model of training for athletic performance. Australian Journal of Sports Medicine. 1975;7:57-60.
  3. Allen H, Coggan A. Training and Racing with a Power Meter. 2nd edition. Boulder, Colorado: VeloPress; 2010.
  4. Apple Developer Documentation. Foundation Models. developer.apple.com/documentation/foundationmodels
  5. Bluetooth SIG. Specifications: Heart Rate, Running Speed and Cadence, Cycling Speed and Cadence, Cycling Power and Fitness Machine profiles. bluetooth.com/specifications/specs

Research is cited for where an idea comes from. None of these authors or organisations has reviewed or endorsed Apex.