FTP Testing Complete Guide: How to Find Your Cycling Power Threshold

You can't train effectively without knowing your FTP. It's the single most important number for cyclists, runners, and triathletes—the foundation for every training zone, workout prescription, and performance metric. Yet most athletes either never test it, test it incorrectly, or avoid retesting out of fear.

After hundreds of FTP tests (and plenty of mistakes along the way), here's your complete guide to finding your Functional Threshold Power, Threshold Pace, and Critical Swim Speed—with protocols that actually work.

What Is FTP and Why Does It Matter?

FTP (Functional Threshold Power) for Cyclists

Definition: The maximum average power you can sustain for approximately 1 hour without fatiguing. Measured in watts.

Why it matters:

• Sets all training zones (Zone 2 endurance, Zone 4 threshold, Zone 5 VO2max)
• Determines workout targets ("3x10min @ 95% FTP")
• Tracks fitness progression over time
• Calculates power-to-weight ratio (FTP ÷ body weight in kg)
• Enables accurate TSS (Training Stress Score) calculation

Threshold Pace for Runners

Definition: The fastest pace you can sustain for approximately 1 hour (or 10K race pace for most runners). Measured in min/mile or min/km.

Why it matters:

• Sets all training paces (easy, tempo, threshold, VO2max)
• Determines race pacing strategy
• Tracks running fitness improvements
• Calculates Training Stress Score for running

CSS (Critical Swim Speed) for Swimmers/Triathletes

Definition: The fastest pace you can theoretically hold indefinitely (in practice, sustainable for 20-30 minutes). Measured in seconds per 100m.

Why it matters:

• Sets swim training zones and paces
• Determines race pacing for open water swims
• Tracks swim fitness progression

The Gold Standard: 20-Minute FTP Test (Cycling)

The most common and practical FTP test for cyclists. You ride all-out for 20 minutes, then multiply average power by 0.95 to estimate 1-hour FTP.

The Protocol

Total duration: 45-50 minutes

1. Warmup (15-20 minutes):
   • 5min easy spinning (Zone 1-2, 100-150W)
   • 3x1min fast pedaling at 100rpm (not hard, just fast cadence)
   • 5min at tempo pace (Zone 3, ~70-80% effort)
   • 1x5min all-out effort to prime legs
   • 5min easy recovery spinning
2. Main effort (20 minutes):
   • GO ALL OUT for 20 minutes—maximum sustainable effort
   • Don't start too hard—aim for negative split (second 10min slightly faster than first 10min)
   • Focus on smooth, steady power output
   • Cadence: 85-95rpm typically optimal
3. Cooldown (10-15 minutes):
   • Easy spinning to clear lactate

Calculating Your FTP

Formula: Average Power (20min) × 0.95 = FTP

Example:

• 20-minute average power: 275W
• FTP = 275 × 0.95 = 261W

Why 0.95? Most riders can hold slightly higher power for 20 minutes than they can for a full hour. The 5% reduction accounts for this.

Execution Tips

Pacing strategy:

• Minutes 0-5: Build into effort, ~95% of target power (don't blow up early!)
• Minutes 5-15: Settle into maximum sustainable pace, ~100% target power
• Minutes 15-20: Give everything left, ~105% target power

Common mistakes:

• Starting too hard: First 5 minutes feel easy, last 10 minutes you die
• Being too conservative: Finish with energy left—you should have nothing at 20 minutes
• Poor warmup: Legs aren't primed, first 10 minutes wasted
• Wrong gearing: Use gear that allows 85-95rpm, not grinding at 60rpm

Indoor vs Outdoor Testing

Indoor (trainer):

• Pros: Consistent conditions, no traffic/stops, easier pacing
• Cons: No cooling, mentally harder
• Best for: Most athletes, year-round testing

Outdoor (road):

• Pros: Natural cooling, mentally easier, real-world conditions
• Cons: Traffic lights, wind, hills make pacing difficult
• Best for: Athletes with access to uninterrupted 20min climb or time trial course

Alternative FTP Test: The Ramp Test

Shorter, less mentally demanding, but equally accurate for most athletes.

The Protocol

Total duration: 25-30 minutes

1. Warmup (10 minutes): Easy spinning with 2-3 short accelerations
2. Ramp test:
   • Start at very easy power (e.g., 100W)
   • Increase power by 20W every minute
   • Continue until failure (can't maintain power for full minute)
   • Record final completed 1-minute power
3. Cooldown (10 minutes): Easy spinning

Calculating FTP from Ramp Test

Formula: Maximum 1-Minute Power × 0.75 = FTP

Example:

• Failed at 340W (couldn't complete 340W minute)
• Last completed minute: 320W
• FTP = 320 × 0.75 = 240W

Pros and Cons

Pros:

• Shorter total time (25min vs 50min)
• Less mental suffering than 20min test
• Accurate for most athletes
• Good for frequent retesting

Cons:

• May overestimate FTP for athletes with strong anaerobic capacity
• May underestimate FTP for time trial specialists with exceptional 1hr power

Running FTP: Threshold Pace Testing

The 30-Minute Time Trial Test

Protocol:

1. Warmup (15 minutes):
   • 10min easy jogging
   • 4x20sec strides with walk recovery
   • 2min easy jogging
2. Main effort (30 minutes):
   • Run maximum sustainable pace for 30 minutes
   • Flat, uninterrupted course (track, bike path, or treadmill)
   • Record average pace
3. Cooldown (10 minutes): Easy jogging

Result: Your average pace for the 30 minutes = Threshold Pace

Example: Ran 30min at 7:15/mile average = Threshold Pace is 7:15/mile

Alternative: Use Recent 10K Race Pace

For most runners, 10K race pace ≈ Threshold Pace

If your recent 10K time is 45:00:

• Pace = 45:00 ÷ 6.2 miles = 7:15/mile
• Threshold Pace = ~7:15/mile

Setting Training Zones from Threshold Pace

Threshold Pace: 7:00/mile

Zone 1 (Recovery): 8:15-8:45/mile (120-125% of threshold)
Zone 2 (Easy): 7:45-8:15/mile (110-120% of threshold)
Zone 3 (Tempo): 7:15-7:30/mile (103-110% of threshold)
Zone 4 (Threshold): 6:50-7:10/mile (95-103% of threshold)
Zone 5 (VO2max): 6:20-6:40/mile (90-95% of threshold)
Zone 6 (Anaerobic): <6:20/mile (<90% of threshold)

Swimming: Critical Swim Speed (CSS) Test

The Protocol

Requires two time trials in one session:

1. Warmup (400-800m): Easy swimming
2. Test #1: 400m time trial
   • Swim 400m as fast as possible
   • Record time in seconds
   • Rest 10 minutes easy swimming
3. Test #2: 200m time trial
   • Swim 200m as fast as possible
   • Record time in seconds
4. Cooldown (200-400m): Easy swimming

Calculating CSS

Formula: CSS = (400m - 200m) ÷ (T400 - T200)

Example:

• 400m time = 360 seconds (6:00)
• 200m time = 165 seconds (2:45)
• CSS = (400 - 200) ÷ (360 - 165) = 200 ÷ 195 = 1.026 m/s
• Convert to pace per 100m: 100 ÷ 1.026 = 97.5 seconds per 100m
• CSS Pace = 1:37/100m

Setting Swim Training Zones from CSS

CSS: 1:30/100m (90 seconds per 100m)

Zone 1 (Easy): 1:45-2:00/100m
Zone 2 (Endurance): 1:35-1:45/100m
Zone 3 (Tempo): 1:25-1:35/100m
Zone 4 (Threshold): 1:20-1:30/100m
Zone 5 (VO2max): 1:15-1:20/100m

How Often Should You Retest FTP?

Recommended testing frequency:

• Every 4-6 weeks during build phase: Fitness is improving rapidly, zones need updating
• Every 8-12 weeks during base phase: Fitness improves slowly, less frequent testing needed
• After significant training break: 2+ weeks off requires retest to reset zones
• Before race season: Establish baseline for season planning
• Mid-season check: Verify training is working

Don't overtest: FTP tests are fatiguing. Testing every week is overkill and disrupts training.

Common FTP Testing Mistakes

Mistake #1: Testing When Fatigued

Problem: Testing after hard training week, results don't reflect true fitness
Fix: Test on fresh legs—after 2-3 easy days or at start of recovery week

Mistake #2: Inconsistent Testing Conditions

Problem: Test indoors in January, outdoors in July—can't compare results
Fix: Use same conditions for all tests (same trainer, same course, same time of day)

Mistake #3: Not Warming Up Properly

Problem: Start test with cold legs, waste first 5-10 minutes warming up during test
Fix: Minimum 15-minute warmup with efforts to prime neuromuscular system

Mistake #4: Testing Too Frequently

Problem: Testing every 1-2 weeks disrupts training, causes unnecessary fatigue
Fix: Test every 4-6 weeks maximum

Mistake #5: Avoiding Retesting

Problem: Fear of worse result, train on outdated zones for months
Fix: Accept that FTP fluctuates—retesting ensures accurate training zones

Interpreting Your FTP Results

Power-to-Weight Ratios (Cycling)

FTP alone doesn't tell the full story—power-to-weight ratio matters for climbing and racing:

Recreational: 2.0-2.5 W/kg
Cat 5/Beginner racer: 2.5-3.0 W/kg
Cat 4: 3.0-3.5 W/kg
Cat 3: 3.5-4.0 W/kg
Cat 2: 4.0-4.5 W/kg
Cat 1: 4.5-5.0 W/kg
Pro/Elite: 5.0+ W/kg

Example: 250W FTP, 70kg bodyweight = 3.57 W/kg (solid Cat 3 level)

Threshold Pace Benchmarks (Running)

Beginner: 9:00-10:00/mile
Intermediate: 7:30-9:00/mile
Advanced: 6:30-7:30/mile
Elite: 5:30-6:30/mile
Professional: <5:30/mile

Using FTP to Set Training Zones

Cycling Power Zones (from FTP)

FTP: 260W

Zone 1 (Active Recovery): <143W (<55% FTP)
Zone 2 (Endurance): 143-182W (55-75% FTP)
Zone 3 (Tempo): 182-218W (75-90% FTP)
Zone 4 (Threshold): 218-243W (90-105% FTP)
Zone 5 (VO2max): 243-312W (105-120% FTP)
Zone 6 (Anaerobic): >312W (>120% FTP)

The Bottom Line: Test Regularly, Train Accurately

FTP testing isn't fun—it hurts. But it's the foundation of effective training. Without accurate zones, you're guessing:

• Training too hard on easy days (accumulating fatigue)
• Training too easy on hard days (no adaptation stimulus)
• Can't track if training is actually working

Test every 4-6 weeks. Accept that FTP fluctuates (that's normal). Use accurate zones for all workouts. Track progress over months, not weeks.

Ready to train with accurate zones? Use TrainingDojo to generate training plans automatically calibrated to your FTP, threshold pace, or CSS. Input your test results, get workouts prescribed in precise power/pace targets—no more guessing.