Create and manage training targets

Once polar-flow-mcp is running and your Polar account is linked, you manage workouts through plain-language Claude conversations. This guide covers the intensity vocabulary and the create / list / edit / delete flow, with worked examples.

Tip

Install the polar-flow skill first. It teaches Claude which tool to call and how to chain reads and writes safely, so you can speak in plain language rather than tool arguments.

Intensity vocabulary

Polar Flow uses five zones (Z1–Z5) on each of three metrics: heart rate, power, and speed/pace. When creating training targets, you specify HR intensity using either a label (preferred) or a numeric zone; power and speed intensity use a numeric zone only.

Label	HR zone	Coaching meaning
easy	Z1–2	Recovery pace. Conversational, fully aerobic. Shakeout runs, warm-ups, recovery jogs.
aerobic	Z2	Easy aerobic / base building. Comfortable, sustainable for long runs. Bulk of weekly volume.
tempo	Z3	Steady-state, comfortably hard. Marathon to half-marathon effort.
threshold	Z4	Lactate threshold. Hard, sustainable for ~30–60 min. Classic 1km repeats, cruise intervals.
vo2max	Z5	Very hard. Short repeats (1–5 min) at near-maximal aerobic effort.

The label → zone mapping is a fact of the API, not a coaching opinion. Prefer labels in conversation — they are more readable. Use a numeric zone (hr_zone: 4) only when someone explicitly says “zone 4”; precedence when more than one intensity key is given is hr_zone > power_zone > speed_zone > label.

For cycling (or another power-capable sport) and pace-based work, use power_zone (1–5) or speed_zone (1–5) instead. Both are zone indices, not raw watts or km/h/min-per-km values — Polar Flow has no field for a literal physical threshold on a phase. Each zone’s actual range is computed from the athlete’s Sport Profile (FTP, threshold pace), which this server doesn’t read; if someone gives you a wattage or pace target, ask which zone it falls in rather than converting it.

Create a workout

Ask Claude for the session you want:

“Create a 5x1km threshold session with 2-minute recovery for next Thursday”

Claude resolves the date, maps “threshold” to Z4, and calls create_training_target with the phase tree:

{
  "name": "5x1km Threshold",
  "date": "2026-05-21",
  "time": "18:00",
  "sport_id": 1,
  "phases": [
    { "type": "warmup", "duration_s": 600 },
    {
      "type": "repeat",
      "reps": 5,
      "goal": { "distance_m": 1000 },
      "intensity": { "label": "threshold" },
      "recovery": { "duration_s": 120 }
    },
    { "type": "cooldown", "duration_s": 300 }
  ]
}

The new target shows up in the Polar Flow diary immediately, and Claude reports the target ID so you can reference it later.

Two things worth knowing about the structure:

• repeat blocks need at least 2 reps. A single continuous zoned effort — “40 minutes at threshold”, “8 km at tempo” — is one block phase (see Zoned steady effort below), not a repeat; an unzoned one with no structure is a simple run (see below).
• Warm-up and cool-down are not added automatically — they’re a coaching choice. The only defaults the tool itself applies are time = 18:00 and sport_id = 1 (running).

See the create_training_target reference for the full argument schema.

Create a simple run (VOLUME target)

For an easy run with no interval structure, you don’t need phases at all — just a total duration or distance:

“Put an easy 35-minute run on Friday”

{
  "name": "Easy 35 min",
  "date": "2026-06-14",
  "duration_s": 2100,
  "sport_id": 1
}

This is a VOLUME target: set exactly one of duration_s, distance_m or kcal (a calorie goal, e.g. "kcal": 500) and omit phases. A VOLUME target has no intensity field at all — if the effort needs a zone, use a phases list instead (see below).

Two more goal-less or single-line shapes:

• No goal at all — leave out every goal argument and the target is FREE: just the sport on that day (“Run on Sunday, whatever I feel like”).

• Race pace — give both duration_s and distance_m and the watch paces you to that distance in that time:

  “10 km in 45 minutes on Saturday morning”

  { "name": "10k @ 4:30", "date": "2026-06-20", "time": "08:00",
    "duration_s": 2700, "distance_m": 10000 }

Zoned steady effort (no intervals)

For a single continuous zoned effort and no warm-up/cool-down/interval structure, use one block phase with intensity set and a custom name — it does not need to be wrapped in a repeat. Its goal is duration_s or distance_m:

“40-minute tempo run tomorrow, no warmup”

{
  "name": "Tempo run",
  "date": "2026-06-15",
  "sport_id": 1,
  "phases": [
    { "type": "block", "name": "Tempo run", "duration_s": 2400,
      "intensity": { "label": "tempo" } }
  ]
}

Race plan by distance segments

Chain block phases to pace a race or long run by km segments, each with its own zone or zone range (zone_max makes the zone a range’s lower bound):

“Half-marathon on the 25th at 9:00: km 1–5 low Z3, km 5–15 Z1 to Z3, then free up to Z4”

{
  "name": "Semi-marathon",
  "date": "2026-10-25",
  "time": "09:00",
  "sport_id": 1,
  "phases": [
    { "type": "block", "name": "Km 1-5", "distance_m": 5000,
      "intensity": { "hr_zone": 3 } },
    { "type": "block", "name": "Km 5-15", "distance_m": 10000,
      "intensity": { "hr_zone": 1, "zone_max": 3 } },
    { "type": "block", "name": "Km 15-21", "distance_m": 6100,
      "intensity": { "hr_zone": 3, "zone_max": 4 } }
  ]
}

Nested intervals and manual phases

A repeat can hold its own phases — any number of them, including one more repeat (as in the Flow editor, which allows two levels). manual: true on a phase makes the watch wait for a lap press before moving on, handy for a rest whose length depends on the athlete:

“3 sets of: 400 m in Z4, then 2 × (30 s sprint, 30 s float), then walk until I’m ready”

{
  "name": "Ladder sets",
  "date": "2026-06-18",
  "phases": [
    { "type": "warmup", "duration_s": 900 },
    { "type": "repeat", "reps": 3, "phases": [
      { "type": "block", "name": "400", "distance_m": 400, "intensity": { "hr_zone": 4 } },
      { "type": "repeat", "reps": 2, "phases": [
        { "type": "block", "name": "Sprint", "duration_s": 30, "intensity": { "hr_zone": 5 } },
        { "type": "block", "name": "Float", "duration_s": 30, "intensity": { "label": "easy" } } ] },
      { "type": "block", "name": "Walk", "duration_s": 120, "manual": true } ] },
    { "type": "cooldown", "duration_s": 600 }
  ]
}

A nested repeat can’t be the last phase of its parent: Polar would flatten it and drop its reps, so the tool refuses it — put a phase after it (here, “Walk”). Limits follow Polar’s editor: 2–99 reps, at most 20 phases as written and 200 once repeats are unrolled.

Multi-sport targets

For a brick or a duathlon, give exercises — one entry per sport, each with sport_id and its own goal — instead of the single-sport arguments. Every sport needs the same kind of goal (all phases, all one volume metric, all a race pace, or none):

{ "name": "Brick", "date": "2026-06-21",
  "exercises": [
    { "sport_id": 2, "phases": [ { "type": "block", "distance_m": 30000, "intensity": { "power_zone": 2, "zone_max": 3 } } ] },
    { "sport_id": 1, "phases": [ { "type": "block", "duration_s": 1200, "intensity": { "hr_zone": 3 } } ] }
  ] }

Polar’s update can’t add or remove a sport, so editing a multi-sport target means sending all of its sports in exercises, in the order get_training_target lists them; to change the set of sports, delete the target and create it again.

List upcoming workouts

“What do I have planned this week?” / “Show me my workouts for the next two weeks”

Claude calls list_training_targets with from_date set to today and to_date set to the end of the requested range (default: today through +30 days), then formats the result as a readable summary with each target’s ID, name, date, and sport.

Edit a workout

update_training_target is a full replace — there are no patch semantics. To change one field, Claude first reads the target with get_training_target, modifies the returned body, then writes it back with the same shape plus the target_id. Just ask:

“Move Thursday’s threshold session to Friday at 07:00”

Delete a workout

“Delete the threshold session on Thursday” / “Remove the workout with ID 12345”

If you didn’t give an ID, Claude lists matching targets, confirms which one you mean (name + date), then calls delete_training_target. If the target was already removed (e.g. through the Polar app), Claude tells you plainly — that is not an error.

Worked examples

Simple interval session

“Create a 5x1km threshold session with 2-minute recovery for next Thursday”

One workout with warmup, five 1km threshold repeats with 2-minute recoveries, and a cooldown, scheduled for that Thursday.

Mixed-zone workout

“3x1km at threshold, then 2x500m at vo2max, this Saturday”

{
  "name": "Threshold + VO2max ladder",
  "date": "2026-05-15",
  "phases": [
    { "type": "warmup", "duration_s": 600 },
    {
      "type": "repeat", "reps": 3,
      "goal": { "distance_m": 1000 },
      "intensity": { "label": "threshold" },
      "recovery": { "duration_s": 90 }
    },
    {
      "type": "repeat", "reps": 2,
      "goal": { "distance_m": 500 },
      "intensity": { "label": "vo2max" },
      "recovery": { "duration_s": 180 }
    },
    { "type": "cooldown", "duration_s": 300 }
  ]
}

Power-zone cycling intervals

“5x4 minutes at power zone 4, 3 minutes easy between, on the bike Sunday”

{
  "name": "5x4min Power Z4",
  "date": "2026-05-17",
  "sport_id": 2,
  "phases": [
    { "type": "warmup", "duration_s": 600 },
    {
      "type": "repeat", "reps": 5,
      "goal": { "duration_s": 240 },
      "intensity": { "power_zone": 4 },
      "recovery": { "duration_s": 180 }
    },
    { "type": "cooldown", "duration_s": 300 }
  ]
}

power_zone is a Polar zone index (1–5), not a wattage — see Intensity vocabulary above. Use speed_zone the same way for pace-based work on foot or bike.

Building a marathon plan iteratively

“Build me a 12-week marathon plan starting in three weeks”

For a multi-session plan, Claude asks clarifying questions first (peak mileage, long-run day, rest days), proposes week 1 for your review, then creates sessions one week at a time after confirmation. This keeps you in control and prevents accidental calendar pollution.

What the tools do not support (yet)

• Raw power/pace thresholds — power_zone and speed_zone only accept a Polar zone index (1–5); there’s no way to target a literal wattage or min/km pace, on this server or in the underlying Polar Flow API itself.
• Adding or removing a sport on an existing target — Polar’s update keeps the sports it isn’t sent and ignores new ones; delete and recreate.
• Activity uploads — this server can read completed sessions (summary + details), but it does not create them from device data. Polar’s app/watch is the source of truth. (You can log a manual result — see create_training_session.)
• Polar account creation or device sync — outside this server’s scope.