Cycling

Set "sport": "cycling" in settings to include cycling-specific outputs.

Cycling outputs

"cycling": {
  "pmax_watts": 490,
  "ltp_watts": 251,
  "ftp_watts": 361,
  "ltp_duration_min": 67,
  "ftp_pct": 0.74,
  "ltp_wkg": 3.49,
  "ftp_wkg": 5.02,
  "lthr_pct": 0.87,
  "lthr_bpm": 155,
  "power_zones_watts": {
    "z1_max": 199, "z2_max": 271, "z3_max": 325,
    "z4_max": 379, "z5_max": 433, "z6_max": 542, "z7_max": 490
  },
  "thresholds_watts": {
    "V0": 119, "V1": 185, "V2_ltp": 251, "V3": 317, "V4": 384, "Pmax": 490
  }
}

Key metrics

LTP (Lactate Threshold Power)

The power at your actual lactate threshold — the V2 threshold on the V-scale. Unlike FTP, LTP is a physiological boundary, not a duration-based estimate.

LTP duration = 12 × 10^E minutes — how long you can sustain LTP. This ranges from ~30 minutes (E=0.40) to over 100 minutes (E=0.90). FTP assumes 60 minutes for everyone — LTP individualizes it.

FTP (Functional Threshold Power)

ftp = Pmax × (0.40 + 0.45 × E)

The power sustainable for exactly 60 minutes. At E=0.70 (population average), FTP ≈ LTP because threshold duration ≈ 60 min. For riders with E above or below 0.70, FTP and LTP diverge.

LTHR (Lactate Threshold Heart Rate)

lthr = HRmax × (0.78 + 0.12 × E)

Ranges from 78% of HRmax (low endurance) to 90% (high endurance).

W/kg

Both LTP and FTP are also provided as watts per kilogram when weight is available.

Power zones

Seven zones in watts, derived from FTP:

Zone	Name	Upper bound
Z1	Active Recovery	55% FTP
Z2	Endurance	75% FTP
Z3	Tempo	90% FTP
Z4	Threshold	105% FTP
Z5	VO2max	120% FTP
Z6	Anaerobic	150% FTP
Z7	Neuromuscular	Pmax

Power thresholds

All V-scale thresholds are provided in watts: V0 (fat/carb crossover), V1 (aerobic threshold), V2 (LTP/lactate threshold), through Pmax.

Input format for cycling

For power meter data, pass speed = power / 100 in the data array. The model fits HR kinetics against this power proxy. The output then gives Pmax, LTP, and FTP directly in watts (the speed values × 100).