What Is FTP (Functional Threshold Power) And How to Improve It

Clem Duranseaud
1 day ago
4 min read

Most triathletes don’t have a motivation problem, they have a precision problem. Having trained for my first Iron Man without a power meter, I know exactly how that feels.

I trained hard. I show up consistently. But when it came to the bike, my efforts was based on feel alone. Some days I push too hard and burned out. Other days I left performance on the table.

The result? My knee blew up after the bike and I had to walk the marathon.

If you want to get faster on the bike, and still have legs for the run, you need a clear benchmark.

That’s where FTP comes in.

Walking the marathon, at least it was nice out (Whistler)

What Is FTP?

FTP stands for Functional Threshold Power.

In simple terms, it’s the maximum power (measured in watts) you can sustain for about 60 minutes.

Think of it as your redline pace on the bike:

Push above it and you fatigue quickly
Stay just below it and you can hold the effort for a long time

A simpler way to frame it:

FTP is the hardest effort you can maintain without blowing up.

This single number becomes the foundation for structuring your training and pacing your races.

Why FTP Matters for Triathletes

FTP isn’t just for cyclists chasing numbers. It’s one of the most practical tools you can use as a triathlete.

Here’s why:

1. It Solves the Pacing Problem

One of the biggest mistakes in triathlon is going too hard on the bike.

If you ride above your capacity early on:

Your heart rate drifts up
Your legs accumulate fatigue
Your run performance drops off a cliff

With FTP, you can anchor your effort:

Sprint distance: ~90–100% FTP
Olympic: ~85–95% FTP
Half Ironman: ~75–85% FTP

Instead of guessing, you ride with control.

2. It Makes Training Measurable

“Hard ride” isn’t a metric.

FTP gives you:

Clear training zones
Repeatable workouts
Objective progress tracking

You’re no longer relying on motivation—you’re following a system.

3. It Shows Real Progress

Speed can vary with terrain, wind, and conditions.

Power doesn’t.

If your FTP increases from 220W to 250W, you’ve improved, no debate.

How to Test Your FTP

You don’t need a lab test to get started. The most practical method for most triathletes is the 20-minute FTP test.

Step-by-Step:

1. Warm-Up (10–15 minutes)

Easy spinning
Include 2–3 short efforts (30–60 seconds) to wake up the legs

2. 20-Minute Effort

Ride as hard as you can sustain for the full 20 minutes
The goal is steady output, not a sprint start

3. Calculate Your FTP

Take your average power for the 20 minutes
Multiply it by 0.95

Example:

Avg power = 240W
FTP = 240 × 0.95 = 228W

Key Testing Tips

Start slightly conservative, you can always build
Aim for even pacing (avoid spikes)
Do the test when you’re rested
Use the same setup each time for consistency

This number doesn’t need to be perfect. It just needs to be consistent enough to guide your training.

Warning: this test is absolutely brutal. I you feel like you want to quite 5 minutes in, you're doing it right. I usually lay on the floor for a good 10 minutes questioning my life decisions when I finish it.

How to Use FTP in Training

Once you have your FTP, you can structure your sessions with purpose.

1. Zone 1: Recovery (<50% FTP)

Recovery pace
Feels very easy

2. Zone 2: Endurance (56-75% FTP)

Aerobic base development
Improving fat oxidation and aerobic efficiency
Increasing mitochondrial density
You can hold a conversation

3. Zone 3: Tempo (76-90% FTP)

Muscular endurance and aerobic development
Improving sustained “comfortably hard” efforts
Increasing fatigue resistance
You can't chit chat for very long

Most triathletes make the biggest gains by spending time just below and around FTP, not constantly going all-out.

4. Zone 4: Threshold (91-105% FTP)

Raises FTP and sustained power
Trains your ability to hold race pace
Improving lactate clearance
Increasing sustainable power output

5. Zone 5: VO2Max (>106% FTP)

Increase aerobic ceiling (VO₂ max)
Trains your ability to hold race pace
Improving lactate clearance
Increasing sustainable power output

How to Improve Your FTP

Improving FTP isn’t about smashing every ride. It’s about applying the right stress, consistently.

Focus on these three methods:

1. Threshold Intervals (Raise Your Ceiling)

These sessions train your ability to sustain high power.

Example Workout:

3 × 10 minutes @ 95–100% FTP
4 minutes easy between efforts

Progression:

Start with shorter intervals (6–8 minutes)
Build up to longer efforts (12–15 minutes)

2. Sweet Spot Training (High Impact, Lower Fatigue)

This is one of the most efficient ways to improve FTP.

Example Workout:

2 × 20 minutes @ 85–90% FTP
5 minutes easy between efforts

You get a strong stimulus without the same recovery cost as all-out threshold work.

3. Easy Volume (Build the Engine)

It’s not flashy, but it works.

Riding at lower intensities:

Improves aerobic capacity
Enhances recovery
Supports long-term progression

Skip this, and your progress will stall.

Sample Weekly Structure

You don’t need a complicated plan. Here’s a simple framework:

1 × Threshold session (short, hard intervals)
1 × Sweet spot session (longer, controlled efforts)
1–2 × Easy rides (Zone 2)
Optional: Brick session (bike + run)

This gives you enough stimulus without burning out.

Common FTP Mistakes

Avoid these, and you’ll progress faster:

Starting Intervals Too Hard

Blowing up halfway through defeats the purpose. Aim for consistency.

Testing Too Often

FTP doesn’t change weekly. Retest every 6–8 weeks.

Ignoring Easy Rides

Not every session should feel hard. Easy work supports hard work.

Chasing Numbers Over Consistency

A slightly lower FTP with consistent training beats erratic high numbers.

Your Action Plan

If you want to start using FTP effectively, keep it simple:

Test your FTP this week
Set your training zones
Add:
- 1 threshold session
- 1 sweet spot session
Keep your easy rides truly easy
Retest in 6–8 weeks

That’s it.

Final Thought

FTP is an important metric to know.

Used properly, it removes guesswork, improves pacing, and gives structure to your training. Over time, small, consistent improvements in FTP translate directly into faster bike splits, and stronger runs off the bike.

If you’re serious about improving your triathlon performance, this is one of the highest-leverage metrics you can start using immediately.

Want a structured plan built around your FTP?

That’s exactly how I program for my athletes—targeted sessions, progressive overload, and clear progression.

Reach out or explore my coaching options to get started.