Less second-guessing. More course until race day.

The endurance companion for runners, trail athletes, and triathletes who want progress without sacrificing real life.

The exact session to do today

No more guessing between push and recover. A clear call grounded in your goal and how you actually feel.

  • Race goal
  • Load and recovery
  • This week's constraints
  • One clear decision

A plan that survives real life

A packed week or a missed session no longer breaks everything. Kaern reorganizes what comes next to protect what matters before race day.

  • Daily adjustments
  • A / B / C priorities
  • Key sessions protected
  • Calendar sync
  • Progress without guilt

Your data, put to work

Connect Polar, Strava, or import FIT files. Kaern turns history into concrete decisions — not another dashboard.

  • Polar & Strava
  • FIT import
  • Volume and load
  • Actionable trends

Ready in three minutes

How it works

1

Connect your training

Polar, Strava, or FIT files — Kaern builds your training context right away.

2

Set your race

Goal A, B, or C — your season is clear, your plan has a direction.

3

Get your upcoming sessions

What to do next — adjusted to your form, your week, and real life.

Private beta · limited spots

Become a Kaern tester

We’re opening the app to a handful of runners, trail athletes, and triathletes who train with Polar, Strava, or FIT files. In exchange for your feedback, you get the coach free for the whole beta.

Who we're looking for

You’re preparing a race — road, trail, or triathlon — and you train regularly. Your sessions go through Polar, Strava, or FIT files.

What you get

Full access to the app on iOS or Android, free for the entire beta, plus a direct line to the maker to shape what comes next.

What we ask

Use Kaern day to day for a few weeks and tell us what works, what’s missing, what’s annoying — one message is enough.

I want to test Kaern

No payment, one-click unsubscribe. Invitations go out in small batches.

A free private beta

Kaern is currently being tested by invitation, with no subscription or payment.

Early access

Now

Open

Invitation-only access to the features available during testing.

  • Free access during the beta
  • No payment method required
  • Features still being improved
  • Direct feedback to the publisher
Join the waitlist

Pro

Coming soon

At launch

A possible future offer whose content and price have not yet been defined.

  • Polar, Strava, or FIT sync
  • A / B / C race goals
  • Frictionless daily coach
  • Adaptive plans
  • Calendar sync
  • Full data sync

If a paid offer is introduced later, its terms will be shown clearly before anyone subscribes.

Endurance is won over months — not one perfect week. Kaern keeps the course when the plan has to move.

— Why Kaern exists
  • Polar & Strava connected
  • Built for running, trail & triathlon
  • Free, invitation-only private beta
Kaern

Inspired by the cairn — the marker that guides you on the trail.

You aim for the race. Kaern keeps the course.

Kaern doesn’t run for you. It tells you what to do next — especially when things don’t go to plan.

Kaern is the personal coach for endurance athletes. Where apps show numbers or force a PDF plan, Kaern adjusts your path every day based on your schedule, recovery, and progress — with AI, so high-level coaching is always within reach.
  • You choose the race and the ambition.
  • Kaern adjusts the path, session by session.
  • Confidence — no dead plan that ignores your fatigue.
  • Consistency over months — not one perfect week, then a crash.
Our story

What Kaern does for you today

From watch sync to today’s session — current features

Connect your data

Polar, Strava, or FIT files — Kaern understands where you’re starting from.

A / B / C goals

Describe your race or let Kaern find it for you. Kaern organizes the season: A (peak), B (key), C (prep).

Daily coach

Fatigue, long runs, race readiness, a goal that changes — a clear answer grounded in your metrics.

Adaptive plans

Structured training that adjusts mid-week and syncs with your calendar.

FAQ

Short answers before you join.

Kaern is currently a private, invitation-only beta used by a small group of friends and family. Features may still change.

Yes. The beta is free, no payment method is required, and billing cannot start automatically. If a paid offer is introduced one day, its price and terms will be shown before you subscribe.

No. Kaern helps organize and adapt training, but it does not replace the judgment of a human coach or advice from a healthcare professional. Its answers may be inaccurate and must always be adjusted to how you actually feel.

A fixed plan follows the calendar. Kaern answers a different question: what to do today when fatigue, work, or a missed session changes things — without guilt-trip catch-up.

Polar and Strava are live today, plus FIT import. Garmin, Coros, and Suunto are next — tell us your device and we’ll notify you when it’s ready.

It is used to provide the features you request. Kaern does not sell your data or use it to train its own AI models. You can disconnect a provider or delete your account and associated data from the app.

No. Kaern does not diagnose injuries or illnesses. If you experience pain, injury, illness, or doubt, stop exercising and consult a healthcare professional.

Claim your priority access

Join the list to hear about the next beta invitations — no spam, we only write when it matters.

Get priority access