{
  "title": "The Mile Record Spec",
  "author": "Alan Destin",
  "event": {
    "date": "2026-07-18",
    "athlete": "Josh Kerr",
    "nationality": "GBR",
    "mark_seconds": 223.16,
    "mark_formatted": "3:43.16",
    "distance_meters": 1609.344,
    "prior_record_holder": "Hicham El Guerrouj",
    "prior_mark": "3:43.13",
    "years_standing": 27,
    "source_url": "https://www.ypradio.org/npr-news/2026-07-18/josh-kerr-of-britain-breaks-27-year-old-world-record-in-the-mile"
  },
  "physiological_constants": {
    "vo2_max_ml_per_kg_min": { "min": 85, "max": 90, "typical": 88 },
    "glycogen_density_g_per_kg_muscle": { "min": 15, "max": 20, "typical": 20 },
    "active_muscle_fraction": 0.4,
    "energy_yield_kj_per_g_glycogen": 16.7,
    "power_output_watts_sustained": 1200,
    "lactate_threshold_percent_vo2_max": { "min": 0.88, "max": 0.92 },
    "body_mass_kg_elite_range": { "min": 60, "max": 65 },
    "thermal_dissipation_watts": { "min": 1200, "max": 1500 }
  },
  "formulas": {
    "average_velocity_ms": "distance_meters / time_seconds",
    "total_o2_demand_ml": "mass_kg * vo2_max_ml_per_kg_min * (time_seconds / 60)",
    "glycogen_store_g": "mass_kg * active_muscle_fraction * glycogen_density_g_per_kg_muscle",
    "energy_needed_joules": "power_output_watts_sustained * time_seconds",
    "glycogen_burn_g": "energy_needed_joules / energy_yield_kj_per_g_glycogen / 1000",
    "excess_power_watts": "power_output_watts_sustained * (1 - lactate_threshold_percent_vo2_max)",
    "lactate_load_mmol_L_proxy": "(excess_power_watts * time_seconds) / 10000",
    "glycogen_deficit_g": "max(0, glycogen_burn_g - (glycogen_store_g * 0.15))",
    "recovery_hours": "glycogen_deficit_g * 10"
  },
  "version": "1.0",
  "published": "2026-07-19"
}