Cycling FTP: Everything You Need to Know
Functional Threshold Power (FTP) is the most important number in structured cycling training. Developed by Dr. Andrew Coggan and popularized by TrainingPeaks and platforms like Zwift and TrainerRoad, FTP represents the maximum average power output sustainable for approximately 60 minutes. Training zones derived from FTP allow cyclists to train with precision, avoiding the "junk miles" trap of training too easy or the burnout risk of training too hard.
Why FTP Matters
FTP serves as the anchor point for all cycling training zones. Without an accurate FTP, prescribed workouts are guesswork. A too-high FTP means every workout is too hard, accumulating excessive fatigue. A too-low FTP means training stimuli are insufficient for adaptation. Accurate FTP testing every 6-8 weeks ensures training zones stay current as fitness improves.
W/kg: The Real Metric
Raw FTP watts matter on flat terrain, but W/kg determines climbing performance. A 90 kg rider with 360W FTP (4.0 W/kg) climbs at the same relative intensity as a 60 kg rider with 240W FTP (4.0 W/kg). For racing, especially in hilly or mountainous terrain, W/kg is the defining performance metric. Pro climbers like Tadej Pogacar and Jonas Vingegaard produce 6.0-6.5 W/kg at threshold during mountain stages.
Test Protocols Compared
The 20-minute test is the original protocol. The 95% multiplier accounts for the fact that maximal 20-minute power is slightly higher than true 60-minute power. This test requires exceptional pacing. The 8-minute test (two intervals with 10-minute recovery) is more forgiving and produces similar accuracy. The ramp test is now the most popular for indoor training: power increases 20W per minute until failure, and FTP = 75% of the last complete minute's power. Critical Power uses two tests at different durations (commonly 3-min and 12-min) to calculate the asymptote of the power-duration curve, considered the most physiologically accurate method.
Training Zone Structure
Coggan's 7-zone system offers fine-grained control for structured training. Zone 1 (Active Recovery, <55% FTP) promotes blood flow without training stress. Zone 2 (Endurance, 56-75% FTP) builds mitochondrial density. Zone 3 (Tempo, 76-90% FTP) develops sustained power. Zone 4 (Threshold, 91-105% FTP) is the primary FTP improvement zone. Zone 5 (VO2 Max, 106-120% FTP) raises the aerobic ceiling. Zone 6 (Anaerobic, 121-150% FTP) develops sprint repeatability. Zone 7 (Neuromuscular, >150% FTP) targets max sprint power.