An AI running coach is most useful for the part of race training that happens between runs: turning a race date into a weekly plan, checking each week against it, and changing the plan when a week goes wrong. In ChatRPE you give it the race, your current weekly distance and your longest recent run, and it builds the block backwards from race day, then logs every run you report against that plan.
This page is for runners who can already run continuously for 30 minutes or so. If you are not there yet, the beginner run-walk plan gets you to a first 5K, and this page picks up from there.
Start with the race date and where you are now
Three numbers decide almost everything about a plan: weeks until the race, how far you run in a typical week now, and your longest run in the last month. Tell the coach those and it can say whether the timeline is comfortable, tight, or better spent on a shorter race first.
The coach keeps the race and goal on file, so next week's conversation starts from them. "Half marathon April 12th, goal is to finish running the whole way" is enough. A time goal works too, and so does changing it in week six.
"Save as a goal: half marathon on April 12th, I want to finish under 2:10. I'm at 15 miles a week across three runs."
Typical block lengths for someone already running regularly look like this. They are starting points, not rules, and a first marathon from a low base often needs longer.
| Race | Usual block | Longest run near the end |
|---|---|---|
| 10K | 6 to 10 weeks | About 8 to 10 miles (13 to 16 km) |
| Half marathon | 10 to 14 weeks | About 10 to 12 miles (16 to 19 km) |
| Marathon | 16 to 20 weeks | About 18 to 20 miles (29 to 32 km) |
Most of the plan is easy running
Race plans across distances share a shape: one long run a week, at most one or two harder sessions, and everything else at an easy, conversational effort. Endurance coaches often describe it as roughly 80% easy, a split drawn from studies of how well-trained endurance athletes actually distribute their training. You do not need a heart rate monitor to follow it. If you can speak in full sentences, the run is easy.
The common mistake is running every run at the same medium-hard effort. It feels productive and leaves you too tired to make the long run or the workout count.
Logging effort with each run makes this visible. "5 miles in 48 minutes, easy, RPE 4" saves distance, time and effort as separate fields. RPE is a 1 to 10 rating of how hard the session felt. Ask the coach to chart pace against effort over the block and you can see whether easy runs are getting faster at the same effort, which is what fitness looks like on a chart. The cardio tracker guide covers how pace is computed from the distance and time you report.
Build mileage without a jump
The familiar "10% a week" rule has weak support as a precise number. The better evidence points the same direction more loosely. In a one-year study of 874 novice runners, those whose weekly distance rose by more than 30% over two weeks had more of certain overuse injuries than those who added under 10%. The authors called the result exploratory.
The practical reading: add distance gradually, hold it for a week or two, and take a lighter week every third or fourth week. Asking "what was my weekly total for the last week?" returns the sum of your logged runs over the last seven days, so you can see a jump before you make it. Charts in ChatRPE plot one point per day, so a daily distance chart shows the runs; the weekly total comes from the question.
A reminder can watch the week for you. It looks at your logged runs before sending, and "this week" means since Monday.
"Every Saturday at 9am, remind me to do my long run, but only if I've logged under 12 miles of running this week."
Weeks where you have already run the miles stay quiet. The accountability guide covers how these reminders work and where they arrive.
The long run, and what to do when you miss one
The long run is the session that makes a race distance feel possible, and it is the one that most often gets pushed by work, weather or a sore calf. Missing one is normal. Trying to make it up by running two long runs in one week, or adding the missed miles to the next one, is how a missed run turns into an injury.
Tell the coach what happened and ask what to change. It reads the plan, your recent runs and what you said, and usually moves the progression back a week rather than stacking distance. If you missed more than one week through illness, say so, because the right restart is lower than where you left off.
A long run log is also where race fueling gets practiced. If you plan to take a gel every 40 minutes on race day, take it on long runs and note how your stomach handled it. "12 miles, 1:58, two gels at 40 and 80 minutes, fine" is one message, and the next long run starts from what worked.
Taper for about two weeks
Cutting volume before a race lets fatigue clear while fitness stays. A meta-analysis of tapering studies found the clearest benefit from a taper of about two weeks, with training volume reduced by roughly 41 to 60% while intensity and frequency stayed the same. The subjects were runners, swimmers and cyclists.
In practice that means fewer miles in the last two weeks (often a bit longer for a marathon), keeping a few short faster efforts so your legs remember race pace, and not testing anything new. Ask the coach to lay out the last two weeks from your race date and it will write them against the volume you actually ran at your peak, not a generic plan's numbers.
Taper weeks often feel worse rather than better: restless, heavy legs, doubt. That is common and usually passes by race morning.
Logging runs when your watch does the tracking
ChatRPE does not sync with a GPS watch, Strava or Apple Health. You report runs in a sentence, by voice or text, or send a screenshot of the watch's summary screen and ask the coach to save it. It reads the distance, time and any other numbers you want kept, such as average heart rate or splits.
You can also run with your phone and have the coach track miles live, which the cardio tracker guide covers. For a race block, the more useful version is a structured workout, such as six 800 m repeats with 90 seconds of jogging between, run as a live session with a countdown for each rep.
"Start a live session: 1 mile easy warm-up, then 6 x 800m at 10K effort with 90 seconds jogging between, then 1 mile easy."
Strength training alongside running
Two short strength sessions a week fit well inside a race block: squats or split squats, a hinge such as a Romanian deadlift, calf raises, and some core work. Keep them away from the day before the long run or a hard workout. How to get stronger explains progressing those lifts; logging them in the same place lets the coach see a heavy leg day before a long run and suggest moving one.
Pain that changes how you run, sharp pain in a bone, or pain that gets worse during a run rather than easing needs a clinician, not a plan that trains around it.
Frequently asked questions
Can an AI running coach write a half marathon training plan?
Yes. Give ChatRPE your race date, your current weekly distance, your longest recent run and how many days you can run, and it builds a plan backwards from race day with a long run, easy runs and any harder sessions you want. Because your runs are logged against it, you can ask each week whether you are on track and have the plan adjusted when a week goes badly.
How many miles a week should I run for a half marathon?
Many first-time half marathoners finish well on 15 to 25 miles (25 to 40 km) a week at their peak, spread over three or four runs, with the long run reaching 10 to 12 miles. More helps if you are chasing a time and your body tolerates it. Build toward your peak gradually rather than starting the plan there.
Does ChatRPE sync with Garmin, Strava or Apple Watch?
No. No watch or Apple Health sync has shipped. You log a run by saying or typing its numbers, or by sending a screenshot of your watch's summary for the coach to read and save. Once saved, the run charts and counts toward weekly totals and reminders the same as any other entry.
How long should a marathon taper be?
Research on tapering points to about two weeks with volume cut by roughly 41 to 60% as the most reliable approach, and many marathon plans use two to three weeks. Keep some short efforts at race pace so your legs stay sharp, and avoid new shoes, foods or workouts in that window.
What should I do if I miss a week of training?
Do not add the missed miles to the following weeks. After a week off for life reasons, most runners can repeat their last normal week. After illness, restart lower and build back over a week or two. Tell the coach what you missed and why, and ask it to shift the plan; it will move the progression rather than squeeze it.