How to Use Claude as Your Running Coach
By Toby Pattullo
Australian Deaflympic marathon and ultra runner, and the solo developer behind IcuSync.
Most self-coached athletes face the same problem. The data is there, weeks and months of it sitting in their training platform, but making sense of it takes time they do not have. Reading graphs, calculating load, deciding what to do next week. It adds up.
Claude does not replace the judgement you have built through years of training. What it does is handle the reading and summarising so you can focus on the deciding.
Here is how to build a simple self-coaching workflow using Claude and IcuSync.
Start with a weekly check-in
The most useful habit you can build is a short weekly conversation with Claude, five minutes, once a week, usually Friday or Sunday. You are not asking Claude to plan your entire season. You are asking it to tell you what last week looked like and help you think about next week.
A simple starting prompt:
Look at my last seven days of training. Summarise my total load, how my fitness and fatigue are trending, and whether my training was consistent. Flag anything that stands out.
Claude will pull your data from Intervals.icu and give you a plain-English summary. Read it, think about whether it matches how you actually felt, and use that as the starting point for your next week.
Give Claude your context
Claude works from your data, but your data does not contain everything. It does not know you are preparing for a half marathon in eight weeks. It does not know your left knee has been a little sore. It does not know you can only train four days this week because of work.
The more context you give, the more useful the output. Before asking Claude to build a workout or review your training, tell it what it needs to know:
I am 10 weeks out from a marathon. I can train five days this week, Tuesday, Wednesday, Thursday, Saturday, and Sunday. My long run is on Sunday. I have been feeling a bit flat this week so I want to keep intensity low and focus on easy volume. What would you suggest?
That is a different conversation to "what should I do this week", and the output will reflect that.
Use it to build workouts, not just analyse
Once you have a sense of what your week needs, ask Claude to build the sessions. Be specific about what you want:
Build me a threshold session for Tuesday. I want about 45 minutes total including warm-up and cool-down. Use my current threshold pace and push it to my calendar for Tuesday.
Claude will write the workout using your zones, structure it correctly, and push it to your Intervals.icu calendar, where it will sync to your watch.
Before it goes to your watch, check it. Does the structure make sense? Does the total duration feel right for where you are in your training? If not, tell Claude:
That feels like too much volume for this week. Can you shorten the main set to three repetitions and keep everything else the same?
Claude will adjust it. This back-and-forth is where it earns its place in your workflow.
Keep your Intervals.icu data clean
Claude is only as good as the data it can read. A few things that make a significant difference:
Set your threshold pace. Go to Intervals.icu Settings → Sport Settings → Run and set your threshold pace. If this is not set, Claude cannot calculate your zones and any workout it builds will have blank or incorrect intensity targets.
Connect your device properly. Make sure your Garmin, Coros, or other device is syncing activities automatically. Claude reads completed activities, if they are not syncing, it is reading an incomplete picture.
Log effort when it matters. Intervals.icu lets you add perceived effort and notes to completed activities. Claude cannot read these notes directly, but keeping your data honest means your fitness and fatigue curves are accurate, which is what Claude is reading when it assesses your load.
What to expect and what not to
Claude will give you useful, coherent output most of the time. Occasionally it will suggest something that does not feel right, a session that is too hard, a volume that is too high, a structure that does not match your training phase.
When that happens, push back. Tell Claude what feels wrong and why. It will adjust. This is normal and expected, the same conversation you would have with a human coach who does not yet know you well.
What Claude cannot do is feel how you feel. It cannot tell you to rest because you look tired. It does not know about the injury that is not in your log. Apply your own judgement to everything it produces, especially when it comes to volume and intensity increases.
Used well, Claude is a thinking partner for your training. It reads the data, structures the sessions, and helps you make decisions. The decisions are still yours.