Unlocking Your Triathlon Potential: Beyond Functional Threshold Power (FTP)
- Paul Gardner
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- Mar 28
- 7 min read
Updated: 2 days ago
Functional Threshold Power (FTP) has become the most talked-about number in endurance sport. It’s simple, easy to test, and gives athletes a clear benchmark for training intensity. But when it comes to racing a triathlon, FTP alone does not determine performance.
Triathlon bike legs are rarely steady-state efforts. Courses include surges, hills, corners, accelerations out of transitions, and tactical pacing decisions that require power above and below threshold. This is why 1-minute, 5-minute, and 20-minute power—along with Critical Power (CP)—often give a more complete picture of race readiness.
The Variability of Power Output
While the power efforts of racing are determined by many factors, a bike leg still sees large variations in power output. Even in a non-drafting, 40km bike on a flat course, a top athlete will spend more than 28% of the bike leg above FTP.
To illustrate this point, the graph below of the power output from an ITU Draft Legal Sprint Podium Finisher shows that light to dark yellow represents efforts right around FTP, with Maximal Aerobic Power (MAP) efforts in orange, and Anaerobic Capacity (AC) and Neuromuscular Power (NM) in red. As you can see, well over 20% of the bike leg was spent at intensities above FTP.
Below, we’ll break down why focusing exclusively on FTP can limit performance. We’ll also explore how a broader power profile and understanding it can lead racers to better pacing and faster race outcomes. But first, let's define what most racers think it is.
FTP Fallacies
1. Misunderstanding FTP Duration
FTP is commonly defined as the highest average power an athlete can sustain for approximately 60 minutes. In real life, it isn't! Search GCN for their user-friendly, anecdotal, and funny videos on various attempts to prove this. For most, it's probably around 30-45 minutes. Those who regularly time trial their bikes know this.
2. The Flawed 20-Minute Test
The best test for establishing FTP is an all-out effort for 20 minutes, multiplied by 0.95. This might work if you're a Cat 1 or pro cyclist, but you're probably not. And it isn't. This test doesn't take into consideration a cyclist's fatigue curve. There are better tests, and you'll find these in all of the race*stronger*® training plans and bike power boosts.
3. FTP Changes During a Ride
Your FTP doesn't stay constant during a ride. Yes, it does change! Do 400 calories worth of work or a hard 45-minute ride. Then do an FTP test. Still think the numbers will be the same?
Maintaining an FTP mark at a taxing steady-state power output means that at some point on a longer ride, the physiological cost of doing that will push you into a different physiological training zone than perhaps you were aiming for. Heart rate will rise with heat, hydration, nutrition, course conditions, stress, and fatigue all contributing. Your fast-twitch/slow-twitch muscle recruitment and the type of physiology you have also muddy the waters. You complete the training but can't work out why you're so tired.
By the way, don't expect your FTP done on a trainer to be the same as one done on the road. Position, motivation, music, bike movement under you, perceived effort, heat, wind (tail or head), kit, helmet, and wheel performance (angle and rolling resistance) all contribute to many athletes posing this question or finding discrepancies in their real-world and indoor expectations.
Athletes with identical FTP values can perform very differently in races because FTP does not describe how well you handle surges or repeated changes in intensity. We'll return to this further down. How your body provides energy, the inflection points you have through genetics and training, and the proportion of fast-twitch versus slow-twitch muscle recruitment you use for your FTP all affect how you achieve your power outputs.
The Impact of Course Conditions
Don't think it's any different for long-course Ironman (IM) and 70.3 racing either. Even in long-course racing, power output fluctuates due to:
Terrain changes
Wind conditions
Overtaking competitors
Technical sections
Nutrition or fatigue variability
Pacing errors
Transition dynamics
See the power output from a professional triathlete’s 4th place finish at IRONMAN Texas, itself a pretty flat albeit very hot course.
You can see that pacing to catch up to the leaders in the first half of the race required lots of MAP and FTP effort before the athlete settled into a sustained General Endurance Tempo effort for the second half of the bike leg to save energy for the run. That’s over 24 minutes at MAP intensity out of the five hours spent on the bike. Texas is flat; imagine what it would be like for Nice!
Why 1-Minute Power Matters
1-minute power reflects your ability to produce high aerobic power with a significant anaerobic contribution. In triathlon, this is important for:
Exiting T1 and accelerating to race pace
Short climbs
Overtaking competitors efficiently
Responding to terrain changes without excessive fatigue
Maintaining speed through technical sections
Athletes with strong 1-minute power can respond to race dynamics without pushing excessively into fatigue that compromises the run. It's also clear that many triathletes don't enjoy the harder intervals. My own experience running the Stages Power Studio at Champneys shows how repeated and consistent 'challenge' intervals ramp up VO2 and top-end power outputs across all abilities.
Why 5-Minute Power Matters
5-minute power is closely related to VO₂max power, which represents the upper limit of aerobic energy production.
A strong 5-minute power helps with:
Medium-length climbs
Bridging gaps
Maintaining speed during surges
Recovering from stochastic pacing patterns
Resilience to repeated intensity changes
Athletes with higher 5-minute power relative to FTP tend to experience less physiological strain when riding above threshold, which translates into better pacing control.
Why 20-Minute Power Still Matters
20-minute power remains valuable because it reflects a large portion of sustained race effort, especially in:
Olympic distance races
Half-distance races
Sustained climbs
Headwind sections
Long steady pacing periods
Introducing Critical Power (CP)
Critical Power provides a more comprehensive understanding of endurance performance than FTP alone. It represents the highest power output that can theoretically be sustained without continual fatigue accumulation. It separates exercise intensity into two domains:
Below CP: Fatigue develops slowly and can be sustained for long durations.
Above CP: Fatigue accumulates rapidly until exhaustion.
Unlike FTP, CP is derived from multiple maximal efforts across different durations. The 'performance' or black label bike power boosts at race*stronger*® include CP testing and also very high-level taxing CP workouts for those seriously fit, serious, motivated, and under 30.
Read on if you're a geek and really want to get better, or skip to 'how CP relates to FTP' lower down.
The Critical Power Relationship
P = CP + W′/t
Where:
P = power output
CP = critical power
W′ (W prime) = finite work capacity above CP
t = time
W′ represents your capacity for efforts above threshold—essentially how much work you can perform when surging or climbing before fatigue forces you to reduce intensity.
For triathletes, W′ strongly influences:
Ability to handle hills without spiking fatigue
Tolerance to repeated accelerations
Ability to stay aero while responding to terrain
Preserving run performance
How to Test for Critical Power
Critical Power is calculated using 2–3 maximal efforts of different durations performed when well rested. A practical field testing protocol:
Option 1: Single Session Protocol
(You'll find this our preferred test in the race*stronger*® bike power boosts)
After a thorough warm-up:
3-minute maximal effort
30 minutes easy recovery
9-minute maximal effort
These two efforts can estimate CP with reasonable accuracy. Just input the results into the attached CP calculator in the 8-week power boost plan.
Option 2: 3-Test Protocol
Perform maximal efforts on separate days:
3-minute all-out effort
5-minute all-out effort
12-minute or 20-minute all-out effort
Plot power vs time and calculate CP using software such as:
TrainingPeaks
WKO
Golden Cheetah
How CP Relates to FTP
For most trained athletes, CP is usually very close to FTP, often within 2–5%. However, CP provides additional insight:
| Metric | What it tells you |
|--------|-------------------|
| FTP | Steady state performance |
| CP | Fatigue boundary |
| W′ | Ability to surge above threshold |
| 1-min power | Anaerobic capacity contribution |
| 5-min power | VO₂max ceiling |
| 20-min power | Sustained race intensity |
Different Horses for Different Courses
Two athletes may both have an FTP of 280W, but:
Athlete A may have high W′ and strong 1- and 5-minute power → performs well on rolling courses.
Athlete B may have low W′ → struggles with repeated surges and experiences run fade.
Why This Matters for Triathlon Racing
Triathlon bike pacing is about minimising physiological cost, not just maximising average power.
Athletes with well-developed short-duration power relative to threshold tend to:
Maintain smoother pacing
Produce fewer costly spikes above CP
Better preserve glycogen stores
Reduce neuromuscular fatigue
Run faster off the bike
In real racing conditions, this often matters more than a small difference in FTP.
Practical Takeaways for Triathletes
Don’t judge fitness from FTP alone.
Track 1-, 5-, and 20-minute maximal power regularly.
Consider modelling Critical Power.
Develop both aerobic ceiling (5-min power) and fatigue resistance (20-min power).
Improve W′ through targeted high-intensity work.
Focus on pacing consistency rather than chasing a single number.
If you're planning on qualifying for a championship or national representation, sort out the kind of athlete you are and the course type that most suits you.
Bottom Line
FTP remains a useful training metric, but triathlon performance depends on a complete power-duration profile. There is room for a different approach to the 80:20 endurance principle. The UAE Emirates cycling team is showing this with their recent sharing of training protocols and the approach of Coach Olav Aleksander Bu with uber triathlon short and long course athletes Kristian Blummenfelt & Gustav Iden.
Your ability to handle surges, recover from intensity changes, and stay metabolically efficient throughout the bike leg has a direct impact on how well you run.
By incorporating 1-minute, 5-minute, and 20-minute power testing, and then training these outputs on your indoor training/turbo sessions, you set yourself up to perform exceptionally well. Athletes gain a clearer picture of race readiness and can train more specifically for the real demands of triathlon competition.
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