Glossary¶

Short definitions for the abbreviations and jargon used across the documentation.

AQI — Air Quality Index¶

A composite score (1–5 on PeakLine's scale) reflecting overall air quality from PM2.5, PM10, NO₂, O₃, SO₂, and CO. Lower is better. Source: OpenWeather. See Weather and air quality.

Anaerobic capacity (Z6)¶

Power zone above ~120% of FTP — short, hard efforts (30 s to ~3 min) that draw heavily on glycolytic metabolism.

Backfill¶

The process of pulling historical activities from Strava that existed before you connected PeakLine. Triggered automatically on first connection (last 30 activities) and on demand for older data.

CTL — Chronic Training Load¶

A 42-day exponentially weighted average of daily training load. Not currently exposed in PeakLine; rolling 28-day SP sum is a rough proxy.

Decoupling¶

The drift between heart rate and power on a steady-state effort, expressed as a percentage. Higher = more fatigue or under-fueling. Eyeball it from the dual zone bars on activity pages.

Endurance (Z2)¶

Power zone roughly 56–75% of FTP, or HR zone 81–89% of LTHR. The "all-day pace" zone, the foundation of most training plans.

FIT file¶

A binary activity-record format used by Garmin and most modern bike computers. PeakLine accepts FIT uploads in the local-file analyzer (Email tier and above).

FTP — Functional Threshold Power¶

The highest average power you can sustain for one hour. Used as the anchor for all power zones, NP, IF, and TSS. Estimated by a 20-minute test × 0.95. See Power and HR zones.

GAP — Grade-Adjusted Pace¶

Pace normalized to flat ground, accounting for the terrain penalty/benefit. Used for runs and trail running. A 5:00/km on a 5% climb might be a 4:20/km GAP.

GPX file¶

An XML-based GPS track format. PeakLine accepts GPX uploads in the GPX Fixer, the local analyzer, and the Route Planner.

HC — Hors Catégorie¶

The hardest climb category. Roughly: a climb score (length × gradient) above 80,000. Mont Ventoux, Stelvio, Alpe d'Huez. See Climbs.

HR — Heart Rate¶

Self-explanatory. Measured in beats per minute (bpm).

HRV — Heart Rate Variability¶

The variation in time between consecutive heartbeats. Measured in ms. Higher = more autonomic-nervous-system recovery. PeakLine reads HRV from Garmin Connect (Strava streams aren't dense enough). See Garmin integration.

IF — Intensity Factor¶

NP ÷ FTP. A normalized 1-hour effort at exactly FTP gives IF = 1.0. A recovery ride sits around 0.6; a hard 20-min test approaches 1.05. Used as the squared term in Stress Points.

Karvonen formula¶

A method for computing HR zones using percentages of HR reserve (HRmax − HRrest). PeakLine uses a Karvonen-style 5-zone model with LTHR as the anchor.

LTHR — Lactate Threshold Heart Rate¶

The HR at which blood lactate begins accumulating sharply. Used to anchor HR zones. Estimated as the avg HR of the final 20 minutes of a 30-minute time trial.

MAD — Median Absolute Deviation¶

A statistical robustness measure used by the GPX Fixer to detect elevation outliers without being thrown off by a single huge spike.

Moving time¶

Time spent actually moving (above a small speed threshold), excluding pauses. PeakLine uses moving time for almost all calculations.

NP — Normalized Power¶

A weighted average that emphasizes hard efforts, giving a more honest "how hard was the ride" number than simple average power. Computed as the 4th root of the mean of power⁴ over 30-second rolling windows.

OSM — OpenStreetMap¶

The crowd-sourced world map. Powers the Route Planner's road network and the snap-to-roads routing.

PLS — PeakLine Score¶

PeakLine's signature 0–1000 single-effort performance metric, distance-aware and elevation-aware. See PeakLine Score.

Polarized training¶

A training distribution heavy in easy (Z1–Z2) and hard (Z4–Z5) work, light on the moderate middle (Z3). Often roughly 80/20.

Power meter¶

A bike sensor that measures the watts you're producing at the pedals (or crank, or hub). The most accurate input for intensity. PeakLine uses power for NP, IF, TSS, and power zones when available.

SP — Stress Points¶

PeakLine's training-load metric, modeled on TSS but with fallbacks for non-power activities. See Stress Points.

Sweet spot¶

A zone overlapping the upper end of Z3 (tempo) and lower end of Z4 (threshold), roughly 88–94% of FTP. Popular target for FTP-building intervals.

TRIMP — Training Impulse¶

An HR-based training load metric, computed from duration × avg HR (zone-weighted). Older than TSS, still useful when no power is available.

TSS — Training Stress Score¶

TrainingPeaks' canonical training-load metric: duration_hours × IF² × 100. PeakLine's Stress Points is a generalization of TSS that adds activity-type coefficients and zone multipliers.

VAM — Velocità Ascensionale Media¶

Vertical ascent rate in meters per hour. Used to compare climbing efforts across different mountains. See Climbs.

VO2max (Z5)¶

The power zone roughly 106–120% of FTP. Intervals at VO2max stress maximum oxygen uptake. Typical interval lengths: 3–8 min.

Webhook¶

A push notification from Strava to PeakLine when a new activity is uploaded. Lets us sync within seconds instead of polling. See Strava integration.

Z1–Z7 (power) / Z1–Z5 (HR)¶

Coggan 7-zone power model and 5-zone HR model. See Power and HR zones for the boundaries.