{
  "calculator": "run-training-paces-calculator",
  "title": "Run Training Paces Calculator",
  "site": "AI Fit Hub",
  "input": {
    "distance": "5k",
    "race_time_minutes": 25,
    "race_time_seconds": 0
  },
  "defaults_used": {},
  "result": {
    "vdot": 38.3,
    "inputRaceDistanceMeters": 5000,
    "inputRaceTimeSeconds": 1500,
    "inputPacePerKmSeconds": 300,
    "zones": [
      {
        "zone": "E",
        "label": "Easy / Long Run",
        "description": "Conversational pace for aerobic base and recovery. Use for most training volume.",
        "pacePerKmSeconds": 393,
        "pacePerMileSeconds": 632,
        "effortPercent": 67,
        "pacePerKmRangeSeconds": [
          363,
          434
        ]
      },
      {
        "zone": "M",
        "label": "Marathon Pace",
        "description": "Your predicted marathon race pace. Race-specific runs for marathon training.",
        "pacePerKmSeconds": 338,
        "pacePerMileSeconds": 544,
        "effortPercent": 81,
        "pacePerKmRangeSeconds": [
          338,
          338
        ]
      },
      {
        "zone": "T",
        "label": "Threshold / Tempo",
        "description": "Comfortably hard: about the pace you could race for an hour. Improves lactate threshold. Max 20 min continuous.",
        "pacePerKmSeconds": 316,
        "pacePerMileSeconds": 509,
        "effortPercent": 88,
        "pacePerKmRangeSeconds": [
          316,
          331
        ]
      },
      {
        "zone": "I",
        "label": "Interval / VO₂max",
        "description": "Hard 3–5 min repeats near VO₂max. Builds aerobic power. Typical rep: 800m–1200m.",
        "pacePerKmSeconds": 285,
        "pacePerMileSeconds": 459,
        "effortPercent": 100,
        "pacePerKmRangeSeconds": [
          285,
          290
        ]
      },
      {
        "zone": "R",
        "label": "Repetition / Speed",
        "description": "Short fast reps (200m–400m) with full recovery. Develops economy and speed.",
        "pacePerKmSeconds": 264,
        "pacePerMileSeconds": 425,
        "effortPercent": 110,
        "pacePerKmRangeSeconds": [
          246,
          274
        ]
      }
    ],
    "equivalentRaceTimes": [
      {
        "distance": "1,500m",
        "distanceMeters": 1500,
        "predictedSeconds": 411
      },
      {
        "distance": "1 Mile",
        "distanceMeters": 1609.344,
        "predictedSeconds": 444
      },
      {
        "distance": "5K",
        "distanceMeters": 5000,
        "predictedSeconds": 1500
      },
      {
        "distance": "10K",
        "distanceMeters": 10000,
        "predictedSeconds": 3113
      },
      {
        "distance": "Half Marathon",
        "distanceMeters": 21097.5,
        "predictedSeconds": 6903
      },
      {
        "distance": "Marathon",
        "distanceMeters": 42195,
        "predictedSeconds": 14275
      }
    ]
  },
  "provenance": {
    "run": "https://aifithub.io/api/run/run-training-paces-calculator?distance=5k&race_time_minutes=25&race_time_seconds=0",
    "page": "https://aifithub.io/run-training-paces-calculator/",
    "methodology": "https://aifithub.io/methodology/run-training-paces-calculator/",
    "contract": "https://aifithub.io/contracts/run-training-paces-calculator.json",
    "engine": "https://aifithub.io/engines/run-training-paces-calculator.js",
    "engine_sha256": "868d099257cf3b58a81e7908fbfff6fde3416877af04d05b7b3fa6e1bf370ab3",
    "build": "f934d40826a83bc97b57de9b7f894502cfdf221d"
  },
  "disclaimer": "General fitness estimates — not medical advice.",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "cite": "AI Fit Hub, Run Training Paces Calculator (engine 868d099257cf), https://aifithub.io/api/run/run-training-paces-calculator?distance=5k&race_time_minutes=25&race_time_seconds=0"
}