How it works
How the coach builds and adapts your week
TextFit’s coach plans from what you tell it, follows fixed training rules, and has every week checked by a validator before it reaches your calendar. The AI writes, explains and adapts the plan. The rules keep it sensible.
In short: you describe your sports, goal, available days and current fitness. The coach builds your first two weeks, about 80% easy with at most two hard days, and a deterministic validator checks each week against the rules below. Workouts go to Garmin Connect or Apple Watch with targets in your numbers. You change the plan by talking to the coach, and every change can be undone.
From download to your first week
- Onboarding questions. Your sports, goal, sessions per week and day off, the time you have, your current fitness per sport and whether you want strength work.
- AI consent. The coach runs on OpenAI, so it needs your permission to send your profile, plan, activities, coach chat and recovery data. OpenAI doesn’t use it to train models. You can turn it off in Settings.
- Connect Garmin or Apple Health, so workouts reach your watch and activities come back.
- The coach builds your first two weeks: the rest of this week and next week.
- Plan preview. The next 7 days: each day’s sport and workout type with its approximate length, or rest.
- Start your 14-day free trial. Then $14.99 a month or $99.99 a year; cancel anytime in your App Store settings.
- Train. The plan is on your calendar and on your watch, ready for the first session.
What the coach plans from
- Sports: running, cycling, swimming, and whether to include strength work.
- Goal: a target event (sport, distance, date, optional target time) or general fitness.
- Sessions per week and your day off, a weekday with no training.
- Time you have: the longest session you can fit on a weekday and on a weekend day.
- Current fitness in your own words, per sport: “10K in 48 min”, “FTP 230”, “1:45 per 100 m”. The coach reads thresholds from it (run threshold pace, FTP, CSS, and max or threshold heart rate when you state them) and keeps your words next to them.
You can change any of it later in the app or in the coach chat.
The rules every week follows
These are fixed. The coach can’t talk its way around them, and the validator checks them in code.
| Rule | What it means for your week |
|---|---|
| 80/20 | About 80% of training time is easy, about 20% moderate or hard. |
| Hard days | At most 2 a week (3 if you train more than 8 sessions), never on consecutive days. Interval and threshold workouts, the long workout and threshold tests all count, across all your sports. |
| Long workout | The week’s longest session in your goal sport, on Saturday or Sunday. For a triathlon: a long ride and a long run on the weekend, which together count as one hard day. |
| Strength | 1 to 2 sessions a week, on an easy day or after the key session of a hard day; never the day before a key or long workout. |
| Progression | Weekly volume grows by no more than 10%. |
| Recovery week | Every 4th week, with volume down 30 to 40% after three build weeks. |
| Phases | Base, then build, then peak, then taper on the way to your event. |
| Time limits | No session is longer than the time you said you have on that kind of day. |
Unknown thresholds: tests come first
If the coach doesn’t know a threshold, it schedules a test in your first week before it writes threshold-based targets for that sport: a 30-minute run test, an FTP ramp test on the bike, or a 400 m + 200 m CSS test in the pool. Each test counts as a hard day. If you’re a beginner in a sport, there is no test in its first four weeks; hard sessions are set by effort or heart rate until then. The FTP test guide covers pacing the bike test.
Targets in your numbers
Every endurance workout is a list of steps with a target: pace for running, watts for cycling, pace for swimming, or heart rate. “2×6 min @ 200–213 W” on your calendar is a range built from your FTP, not a generic zone. Strength workouts are exercises with sets, reps and times.
The next 7 days are pushed to your primary device automatically, Garmin Connect or Apple Watch, and updated when the plan or a threshold changes. More on TextFit with Garmin and TextFit with Apple Watch.
How the plan adapts
There is one coach chat. Write to it the way you would text a coach: “Move my long run to Sunday, I’m travelling”, “I’ve got a cold”, “Plan next week”. Quick actions above the input cover the common requests.
- Every change is visible. When the coach moves, eases, swaps or adds a workout, the change appears in the chat as a coach action with an Undo button.
- Missed workouts stay honest. A workout whose day passed without a matching activity shows as missed. Tell the coach what happened and it adjusts the coming days.
- It remembers what matters: a short summary of your goals, injuries, preferences and standing instructions, in whatever language you write in.
Assessments: workout, form and recovery
Completed activities and recovery data come back from Garmin or Apple Health. The numbers underneath each assessment are computed in code, never estimated by the AI.
Workout
Planned versus actual, including time in target: how many key intervals stayed inside their band (±2% of the power or pace target, ±3 bpm for heart rate) and their share of the key-interval time, for example “4/5 · 82%”. You can add your own 1 to 10 effort rating.
Form
Each activity gets a training load from power, pace or heart rate. Fitness is your long-term load, Fatigue your last 7 days, and Form the difference, so you can see whether you’re building or digging a hole.
Recovery
Last night’s HRV, resting heart rate and sleep are compared with your own normal range over the previous 28 nights and summed up as 🟢, 🟡 or 🔴. On a 🟡 day, Ease today turns today’s hard sessions into one short easy session in the same sport; on a 🔴 day it removes today’s workouts. Each change can be undone.
See the rules applied to a real week on the AI running coach page (half marathon) and the AI triathlon coach page (Olympic distance). Price, devices and data: the FAQ. Comparisons: Runna alternatives, Runna vs Garmin Coach, marathon training apps and triathlon training apps.
See your first week
Answer the onboarding questions and the coach builds your first two weeks, shows you the next 7 days, and keeps them on your Garmin or Apple Watch.
14 days free, then $14.99/month or $99.99/year. Cancel anytime in your App Store settings.