How kurro works

1. 1Connect your data. Link your watch, or import files from it, so kurro can see the runs you already did. No history yet? A few simple questions give your first plan a good starting point.
2. 2Pick your goal. Choose a race and a target time, or simply aim to get fitter. Then tell us which days you can run.
3. 3Start running. Every run makes your plan a little more yours. kurro keeps it up to date, so you never have to rebuild it yourself.

• Your watch. Connect Garmin, COROS, Polar, Suunto, Fitbit or Zepp in Settings → Devices. New runs arrive by themselves. If you allow it, your sleep and recovery data come along too.
• Files. Choose “Import file” on the Activities page to add FIT, GPX or TCX files. You can pick many files at once, even a whole archive from your watch.
• By hand. Trained without a watch? Add the activity yourself with its sport, date and duration. It counts like any other.

Did the same run arrive twice, for example as a file and from your watch? kurro keeps the most detailed copy and sets the other aside. Nothing counts double, and nothing is deleted.

Disconnecting your watch deletes nothing. Your activities and sleep data stay in kurro and keep counting.

Disconnecting Strava is different: it deletes your Strava activities and the history built from them, as Strava requires. You can't undo this, so export your data from Strava first if you want a copy.

Rides, swims and walks count as training, but there are no cycling or triathlon plans.

Pregnant, injured for a long time or unsure about your health? Pause your plan and follow the advice of your doctor or midwife.

• Base: mostly easy running, to build the engine.
• Build: more volume, with steady and threshold work.
• Specific: sessions that look more and more like your race.
• Taper: less volume, a little speed, so you start fresh.

The lighter week comes every fourth week to start with. As kurro learns how you recover, it moves that to every third to sixth week.

A plan for a race looks up to about 26 weeks ahead. Without a race, your plan rolls 12 weeks ahead and keeps moving with you.

A rebuild happens after every run that syncs, after your check-in, after you change a setting, and once more every night around 3 a.m. in your own time zone.

Run more than planned, skip a day or feel tired, and the coming days shift to match. Missing a run never makes your coming weeks harder: the plan simply carries on from where you are now.

Some sessions never move by themselves: sessions you completed, moved or locked, and your races.

Curious why something changed? Open “What changed & why” on your plan, or tap “Why this workout?” on any session for a short explanation.

Choose how many days a week you run, from 1 to 7, which days are off limits, and which day suits your long run.

Need more control? Set rules per weekday. The plan always respects them, and when two rules meet, the strictest one wins.

• No speed work
• No long run
• No strength
• At most a set number of minutes
• No training at all

Busy period, a move or low on motivation? Turn on maintenance mode. You only run easy, at about 60% of your usual weekly volume, until the date you pick. After that, the plan eases you back in.

This week and the next full week show every session with its distance, time and pace. Later weeks show a time range, the mix of sessions and the phase. The range is about 20% wide either way.

Plans change, and that's fine. Drag a session to another day, or use “Move to” in the session itself. Want a session to stay exactly where it is? Lock it, and the plan works around it.

• Apple Watch: with the iOS app, your planned runs for the next 21 days go to your watch automatically, step by step.
• Any watch: on the web, open a session and choose “Download .fit”. Import that file in Garmin Connect, COROS, Polar Flow or any app that accepts .fit workouts.
• Garmin, COROS or Suunto with kurro Pro: turn on “Send sessions to my watch” in Settings → Devices. kurro then sends your sessions for the next 7 days, and updates them when the plan changes.

The training effect is never negative, and it has no hard ceiling: training more or better keeps improving the number, a little less each time. It rests on published research, not on other kurro users.

The goal time assumes you follow the rest of your plan. It always comes with a range, because no honest prediction is exact.

Set your own target, or choose “the best time I can realistically reach”. kurro then tells you plainly where your target stands:

• Comfortably within reach
• On track
• Ambitious, within reach
• A reach, aim realistically
• Not realistically achievable

Is your target out of reach? You still train at a pace you can actually hold. That way you build towards your goal without breaking down on the way.

The training effect counts for races from 5K to the marathon, because that is what the research covers. For other distances, the goal time rests on your fitness alone, and kurro tells you so.

It looks at your personal records, your best efforts of the past year and the races you logged. Recent efforts count most: an effort counts half as much after about 75 days.

From there, a curve fitted to you translates one distance to another. Each time comes with a range and a label: High, Medium or Low confidence.

Your longest recent run limits the label. Without long runs, a marathon prediction stays at Low. Without enough recent runs for a distance, we show nothing rather than guess.

Do you race faster or slower than predicted, time after time? Your own results nudge your predictions, by at most 5%. On the free plan they can only make them slower; with kurro Pro, both ways.

During the taper you run less, but you keep one short session at race pace each week, so your legs stay sharp. The aim is to start your main race fresh, not rusty.

Tell us what the course is like: flat, rolling, hilly or trail. A hilly or trail race brings hill sessions into your build phase. A race with a big descent adds downhill repeats, so your legs are ready for it.

For a run, kurro reads intensity from your pace first, corrected for hills. Then from heart rate, then from power. On a hot or tired day, your heart rate can raise the load of a run.

No pace, heart rate or power? Your own rating of the effort (RPE) is used. A run with only a duration still counts, at a low intensity.

Fitness reacts slowly: it is roughly your average daily load over the last six weeks. Fatigue reacts fast: roughly the last week. After a hard block, fatigue is higher than fitness and form goes negative. That is normal while you train.

Before a race, the taper lets fatigue drop faster than fitness. Your form then rises, ideally to between +10 and +25 on race morning.

From pace: your fastest sustained efforts of at least 1,500 metres in the past year, using the tables of coach Jack Daniels. Easy runs don't count.

From heart rate: steady runs of at least 8 minutes at 88 to 94% of your maximum heart rate, on flat ground.

kurro takes the highest estimate that a second run confirms within 5%. Without recent hard efforts it slowly fades, just like your real fitness.

Your easy pace comes from your own runs: once you have five or more easy runs of 20 minutes in the last eight weeks, kurro uses their typical pace.

No threshold heart rate yet? Then the heart-rate zones use your maximum heart rate. Your zones move along as your fitness changes, and you can set your threshold yourself in Settings.

kurro counts your easy and hard minutes over the last 28 days. With second-by-second data from your watch, every second faster than halfway between your easy and tempo pace counts as hard.

A planned easy run that you completed counts as easy, even without detailed data. Each percent of hard time above 20 costs 5 points, so at 40% hard the score is 0.

With too little tracked data, you see no score rather than a wrong one.

kurro compares each value with your own last 28 days. A night that is just normal for you scores 80. Better than normal scores higher, worse scores lower.

Missing a value? The other values simply weigh a bit more that day. After a session much bigger than usual, the score drops by up to 5 points.

You need a connected watch that tracks sleep, with permission to share sleep and recovery data.

Readiness combines your recovery score, your form, how fast your load went up, and your check-in: how you feel on a scale of 1 to 5, plus any niggle. A bad check-in weighs more than a good one.

When a session gets lighter, only the main part shrinks. Your warm-up and cool-down stay the same, and your race day is never touched. A session you locked or moved also stays as it is: you get advice instead.

Once the pain is 3 out of 10 or less, you return to running in steps. You move up one step at most once a day, and only when it doesn't hurt. Pain of 5 or more stops your running again, whatever step you are on. When the pain is back to 3 or less, you start again at the first step.

Skipped a run? Tell us why. Being sick, injured or short on time never counts as the training being too hard, so your plan doesn't hold you back for the wrong reason.

All of this is part of the free plan. Your health always comes first.

A ride, swim or walk of at least 20 minutes, and at least 60% of the planned time, counts for a planned easy or recovery run. Long runs and quality sessions can't be replaced.

Padel, tennis and golf are great fun, and they add load, but they don't replace an easy run. Strength training doesn't either.

Did a real run sync later for the same day? It takes the place of the cross-training. Is a run linked to the wrong session? Open that session and choose “Undo completion”.

The coach can suggest changes to your plan, but nothing changes until you confirm. It gives no medical advice: for pain or health worries, see a doctor.

Prefer Claude or ChatGPT? Connect them in Settings → AI assistants, and they can read your training. With kurro Pro they can also make changes for you. Those apply right away, without a confirmation step in kurro.

We never make the free plan worse on purpose to push you towards Pro. Safety always stays free: niggles, illness and easing on red days.

Pro costs €4.99 a month or €39.99 a year. Try it free for 14 days.

You can try Pro free once per account. Cancel during the trial and you pay nothing.

Buy it in the iOS app through the App Store, or on the web. Pro belongs to your account, so it works on both. Cancel where you bought it.

Theme, accent colour and units (km or miles) only change how the app looks. They never change your plan.

Want a summary of your week in your inbox? The weekly email is off by default. Turn it on in Settings → Emails.

Changed your mind about sharing health data or using the AI coach? Withdraw your consent in Settings → Privacy & consent. Your account stays.

Want to stop completely? Delete your account in Settings. That removes your data and ends a subscription you pay on the web.