Complete Guide to FTP and Power-Based Training
Functional Threshold Power (FTP) represents the highest power you can sustain for approximately one hour. It's the cornerstone metric for structured cycling training, providing an objective measure of fitness and enabling precise training intensity prescription.
Understanding FTP
FTP corresponds closely to your lactate threshold - the intensity where lactate production exceeds clearance. Below FTP, you're in a sustainable aerobic state. Above FTP, lactate accumulates, leading to fatigue within minutes. Training systematically around FTP improves your sustainable power output.
The Seven Training Zones
Zone 1 (Active Recovery): Easy spinning for recovery. Promotes blood flow without adding training stress.
Zone 2 (Endurance): Aerobic base building. Improves fat metabolism and capillary density. Should comprise 70-80% of training volume.
Zone 3 (Tempo): Challenging but sustainable. Useful for race simulation but not primary training focus.
Zone 4 (Threshold): Just below to just above FTP. Highly effective for improving FTP itself. Classic workouts: 2x20min or 3x15min.
Zone 5 (VO2 Max): Very hard efforts that improve maximum aerobic capacity. Typical intervals: 3-8 minutes with equal rest.
Zone 6 (Anaerobic): Short, very hard efforts (30 seconds to 3 minutes) that develop anaerobic capacity for attacks and steep climbs.
Zone 7 (Neuromuscular): All-out sprints under 30 seconds for power development.
Sweet Spot Training
The "sweet spot" (84-97% FTP) offers excellent returns on investment. It's hard enough to drive adaptation but sustainable enough for significant volume (20-40 minute intervals). Sweet spot training efficiently raises FTP without the recovery demands of traditional threshold work.
Power-to-Weight Ratio
Your watts per kilogram (W/kg) indicates climbing ability and competitive level:
- 2.0-2.5 W/kg: Recreational cyclist
- 2.5-3.5 W/kg: Strong amateur
- 3.5-4.5 W/kg: Competitive amateur/Cat 3-4
- 4.5-5.5 W/kg: Elite amateur/Cat 1-2
- 5.5-6.5 W/kg: Professional domestic
- 6.5+ W/kg: World Tour professional
How to Test Your FTP
20-Minute Test (Recommended): After warm-up, ride as hard as possible for 20 minutes. Your FTP is 95% of average power. Most common protocol due to manageable duration.
30-Minute Test: Longer but more accurate. FTP equals average power for the full 30 minutes. Requires excellent pacing discipline.
Ramp Test: Increasing power every minute until failure. FTP estimated at 75% of final minute power. Quick but less accurate for some riders.
Testing Best Practices
- Test when fresh - avoid hard training 48 hours prior
- Use consistent conditions (same bike, trainer, time of day)
- Warm up thoroughly: 15-20 minutes with some hard efforts
- Pace conservatively early - negative splitting is ideal
- Record conditions, feelings, and any issues for future reference
Training with Power vs Heart Rate
Power is superior for interval training due to instant feedback and no cardiac lag. Heart rate remains useful for monitoring overall training load, detecting overtraining, and pacing long steady efforts where power fluctuates.
Heart rate limitations: 5-15% daily variability from hydration, sleep, stress, and temperature. 10-30 second lag responding to effort changes. Cardiac drift (rising HR at constant power) during long rides. However, an elevated resting heart rate signals need for recovery.
Periodization and FTP
Structure training in blocks:
Base Phase (8-12 weeks): Focus 80-90% in Zones 1-2. Build aerobic engine with volume. FTP improves 5-10% from consistency.
Build Phase (6-8 weeks): Add Zone 4 threshold work (1-2 sessions weekly) and Zone 5 VO2 intervals. FTP gains accelerate with intensity.
Peak Phase (3-4 weeks): Maintain fitness, reduce volume, include race-specific work. FTP stable or slight gains.
Recovery (1-2 weeks): Easy riding only. Let adaptations consolidate. FTP may temporarily dip but rebounds with fresh legs.
Common FTP Training Mistakes
- Too Much Threshold Work: More Zone 4 doesn't equal more gains. 1-2 quality sessions weekly suffices; more causes chronic fatigue.
- Neglecting Zone 2: The "grey zone" trap - riding too hard on easy days, too easy on hard days. Easy days must be truly easy.
- Ignoring Recovery: Adaptation occurs during rest, not training. Schedule recovery weeks every 3-4 weeks.
- Rare Testing: Training with outdated FTP wastes opportunities. Test every 4-6 weeks during build phases.
- Poor Pacing: Starting FTP tests too hard leads to blowing up. Conservative first half, hard second half yields best results.
Improving Your FTP
Threshold Intervals: Classic 2x20min at 95-100% FTP with 5-10min recovery. Or 3x15min, 4x10min variations. Once weekly during build.
Sweet Spot: 2-3x 15-20min at 88-93% FTP. Less fatiguing than true threshold, sustainable twice weekly.
Over-Unders: Alternate above/below FTP (e.g., 2min at 105%, 2min at 95%). Teaches lactate tolerance and FTP pacing.
Tempo Rides: Long steady efforts at 76-90% FTP. Build muscular endurance for sustained hard riding.
Frequently Asked Questions
How accurate is this FTP calculator?
Very accurate when using proper test protocols. The 95% factor for 20-minute tests is validated across thousands of cyclists. Individual variation exists - some riders test well (optimistic FTP), others struggle with pacing (conservative FTP). Adjust if training zones feel systematically wrong.
Can I improve FTP while losing weight?
Yes, but challenging. Moderate calorie deficits (300-500 daily) preserve training quality while losing fat. Aggressive dieting impairs performance and recovery. Prioritize weight loss during base phase when intensity is lower. During build/peak, maintain weight for optimal power gains.
Why does my FTP vary between indoor and outdoor?
Indoor FTP typically 3-7% lower due to heat stress, reduced cooling, and psychological factors. Test in the environment you'll train. If racing outdoors, test outdoors periodically to establish outdoor FTP.
How long until I see FTP improvements?
Beginners: 10-15% gains in 8-12 weeks with consistent training. Intermediate: 5-10% over 12-16 weeks with structured approach. Advanced: 2-5% annual gains, hard-fought. Proper periodization, consistency, and recovery determine progress rate.
Should I train with FTP if I don't have a power meter?
Heart rate zones work well for most training. Perceived exertion is surprisingly accurate with experience. However, power meter provides precision impossible to match otherwise, especially for intervals. Consider a power meter a high-value training investment.
Advanced FTP Concepts
FTP vs CP (Critical Power): CP models your power-duration curve more comprehensively. FTP remains practical for day-to-day training; CP helps understand short power capabilities.
Durability: Maintaining power output despite fatigue. Two riders with equal fresh FTP may have vastly different 3-hour power averages based on durability.
TTE (Time to Exhaustion): How long you sustain 100% FTP varies individually (45-75 minutes). Longer TTE suggests better threshold endurance.
Conclusion
FTP provides an objective, actionable metric for training progression. Understanding your zones enables targeted training that maximizes adaptation while managing fatigue. Test regularly, train smart with appropriate intensity distribution (mostly easy, occasionally very hard), recover adequately, and watch your FTP steadily rise.