Neverpedia

The glossary, defined without bullshit

Cycling and running terms - FTP, CTL, TSS, sweet spot, Zone 2 - explained plainly, with what they mean and how to use them.

Power

CP (Critical Power)

The highest power you can sustain indefinitely from aerobic metabolism alone.

FTP (Functional Threshold Power)

The highest power, in watts, you can sustain for roughly an hour.

NP (Normalized Power)

A weighted average of power that reflects the physiological cost of a variable-intensity ride.

Sweet Spot

Training intensity at roughly 88–94% of FTP — high productivity per unit of fatigue.

Threshold

Intensity at or around FTP/LTHR — the boundary between sustainable and unsustainable effort.

VO2 max

The maximum volume of oxygen your body can consume and use during intense exercise.

W' (W-prime)

The amount of work, in kilojoules, you can do above Critical Power before exhaustion.

LTHR (Lactate Threshold Heart Rate)

The heart rate at which lactate begins to accumulate faster than your body can clear it.

Max HR

The highest heart rate, in beats per minute, you can produce during all-out exercise.

ATL (Acute Training Load)

A 7-day weighted average of your daily training stress — a proxy for fatigue.

CTL (Chronic Training Load)

A 42-day weighted average of your daily training stress — a proxy for fitness.

IF (Intensity Factor)

A workout's Normalized Power divided by your FTP — a simple measure of how hard the ride was relative to threshold.

TSB (Training Stress Balance)

CTL minus ATL — a single number that estimates how fresh or fatigued you are.

TSS (Training Stress Score)

A single number summarizing how much physiological stress a workout produced, scaled to FTP.

Cadence

How many times your legs complete a full pedal stroke per minute (cycling) or steps per minute (running).

Negative split

Completing the second half of an effort or race faster than the first.

Zone 2

Easy endurance riding at 55–75% of FTP — the foundation of aerobic fitness.