Can I Validate My Functional Threshold Power?

It’s all about power.

Power Tap indicator
Power Tap indicator (yellow ).

Of the two main variables in a training program, volume and intensity, volume has been easily measured for decades. On the other hand, intensity has suffered from a lack of accuracy until recently. Power meters can quantify intensity like no other device outside of a laboratory. The power meter revolutionized training and racing.

An Intensity Benchmark

Power Tap wheel hub
Power Tap hub on rear bike wheel

Power is certainly accurate, and relatively easy to measure. But absolute power values are meaningless from one workout to the next. A benchmark had to be developed for the sake of comparisons and that benchmark is called functional threshold power (FTP) 1)Ballinger, A. 2020. What is FTP in Cycling and How Do I Test and Improve It? Cycling Weekly. . What Is Functional Threshold Power. TrainingPeaks. It is most commonly defined as the maximum effort one can sustain for 60 minutes on the bike (Allen et. al, 2019)3)Allen, H., Coggan, A. and McGreggor, S. 2019. Training and Racing with a Power Meter, 3rd ed. Velo Press. Boulder CO.

Functional Threshold Power is a point estimate of a theoretical construct so it is not going to solve all your training problems. But it can be very useful.

Testing FTP

There are different ways to estimate FTP. My coach, Sami, and I use a method similar to that of Friel (2016)4)Friel, J. 2016. The Triathlete’s Training Bible 4th Ed. VeloPress, Boulder, CO. p.47 which involves a 20 minute maximum effort on the bike. For this discussion, let’s call that Max20. The resulting average watts of the 20 minute effort can be multiplied by 0.95 to approximate the actual 60 minute functional threshold power (FTP). In our implementation of the test, there is an extra five minute all-out effort before the 20 minute effort. It gives us a little extra data to play with and as long as each subsequent test has the same protocol, I can compare results among tests to see how my fitness is improving.

Why pedal for 20 minutes to approximate a 60 minute effort?

Sixty minutes of pedaling at your highest constant effort is difficult. In fact, it’s grueling. It is very hard to maintain the power you believe should be your FTP for that amount of time. And in order to perform the test correctly you must have a pretty good idea of what your FTP is going to be before you even start the test so you can pace it correctly.

All of this has lead me to the question:

Can I validate the results of my 20 minute FTP test?


How accurate is FTP20 for predicting a 60 minute effort (FTP)?

Validation vs. Confirmation

I know from the get go that I won’t be able to validate my FTP estimate from a 20 minute test (FTP20).

Statistics. That’s why I can’t validate my FTP20. There is one experimental unit (myself) and, at this point, there is one replicate (one recent measure of FTP20). That’s what they mean when they say, “n equals one.” Therefore, this is not so much a validation, but a confirmation of sorts.

So, to confirm my FTP20, I need to generate a 60 minute all out effort (FTP60) and see if

FTP60 = FTP20 = 0.95 x Max20

The 20 Minute Test (FTP20)

This workout was held on 11/14/2020 and it went something like this:

  • 10′ warm up: easy spin
  • 3 x [60″ @ z3, 60″ @ z1] (z3 can be based on RPE or previous FTP estimate)
  • 5′ @ z1
  • 5′ all out
  • 10′ @ z1 recovery
  • 20′ all out
  • 5′ cool down

‘ = minutes, ” = seconds

Power (watts) generated over the course of the 20 minute FTP test workout
Summary statistics for the 20 minute all-out effort

Average power for the 20 minute effort was 220w. Multiply that by 0.95 and we get FTP = 209w. Now, let’s get a little rest and then confirm that estimate with an “hour of power.”

The 60 Minute Test (FTP60)

After a week of mostly low intensity and low volume training it was time to complete the “hour of power” on 11/21/2020.

Low intensity and low volume preceded the second test in order to allow sufficient recovery from the first test.

This workout was a bit more simple than the previous FTP test.

  • 15′ warm up.
  • 60′ all-out
  • 5′ cool down
Power (watts) generated over the course of the 60 minute FTP test workout
Summary statistics for the 60 minute all-out effort

In the first test of FTP, we determined FTP20 to be 209w. From the table on the right, we can see that the average power for the 60 minute effort (FTP60) was 209w.

I think high power statistics are not necessary to conclude that my FTP60 confirms my FTP20.

Like I said above, I do not consider this a validation. It’s possible that the two estimates are identical by chance. After all, “n equals one.” There are many sources of variation and I accounted for only a few. Also, notice how the minimum power is zero in both tests. During the 20 minute and 60 minute intervals I never stopped pedaling which means either the measuring device in the wheel hub is dropping watts or the head unit is dropping watts. The effect may be inconsequential, but I don’t know for sure.

Another factor that may have affected the outcome is bias. I may not have pedaled as hard as possible on the second test, because I knew what my initial test results were. It’s possible that I subconsciously tried to make the results match. I truly doubt that’s the case because I can not pedal smoothly enough to hold the power output constant so the power meter displays a very large range of numbers. Aiming for one particular number would require a higher level of averaging or smoothing than what I was monitoring.

For now, however, I have a high degree of confidence in my current estimate of FTP and the 20 minute testing protocol.

I’ll Take 20 Over 60 Any Day

The 20 minute test is hard enough. Putting out a maximal sustained effort requires pacing and focus. The 60 minute maximal effort is brutal. If you plan on trying it (and I suggest you do if only because my misery loves your company), here are some of my notes and observations:

  • Both tests were performed on a training stand with hydrostatic resistance.
  • The power meter is a PowerTap® in the hub of the rear wheel.
  • I used my FTP20 as a guide for pacing the 60 minute effort.
  • In the first 10 minutes, I aimed for an average watts of 200 to 205.
  • After that I just tried to increase the power slowly.
  • The effort felt easy for the first 15 minutes.
  • From minute 15 to 30, the effort steadily got harder and harder to maintain the same power. I considered quitting the test.
  • From minute 30 to 45, I was in hell. Too late to quit.
  • In the last 15 minutes hell rejected me so I had no one to blame but myself if I did quit. Something inside kept pushing, but at one point, I begged for the watch to move faster.
  • About 50% of my time was in the aero bars compared to about 60% for the 20 minute test.
  • No video games like Zwift®, Rouvy®, etc.; no music, no videos.

So, in conclusion, it seems that my FTP20 is an acceptable estimator of my FTP. Now on to the next question,

How can I be confident that my FTP is an accurate estimator of my anaerobic threshold?

Until next time…

References   [ + ]

1. Ballinger, A. 2020. What is FTP in Cycling and How Do I Test and Improve It? Cycling Weekly.
2. Anon. . What Is Functional Threshold Power. TrainingPeaks.
3. Allen, H., Coggan, A. and McGreggor, S. 2019. Training and Racing with a Power Meter, 3rd ed. Velo Press. Boulder CO.
4. Friel, J. 2016. The Triathlete’s Training Bible 4th Ed. VeloPress, Boulder, CO. p.47

Triathlon Training: Which Is Better, Numbers Or Feel?

If You Can’t Measure It, You Can’t Manage It.

Anything can be quantified.

For example, did you know that there is a number to indicate the firmness of your bacon? If enough bacon eaters complain about soft bacon, the bacon makers of the world are going to find a way to make it better and the only way they know how to make it better is by quantifying bacon firmness1)Savell, J. and Gehring, K. 2019. Meat Perspectives: Explaining soft bellies and testing firmness. Meat + Poultry.

I can’t make up this stuff. It’s how I make a living… sort of.

I’m the kind of person who sees beauty in numbers and patterns in complex data sets. Therefore, I’m the kind of triathlete who likes to collect numbers: power, pace, heart rate, etc. However, I do have my limits.

The Power of Feel

Is it possible that numbers like watts and beats per minute could distract athletes from getting a true feel for their sport?

How many of us are too busy listening for the Tempo Trainer to beep instead of feeling the arm as it catches the water?

With a heads up display inside the latest gadgety swim goggles, you probably don’t even have to count laps anymore. (Maybe that’s not such a bad thing actually).

Power meters used to be exclusively a bike gadget. Now you can measure run power if you have the right expensive device.

Heart rate? That’s so 90’s. Today you’d better be monitoring heart rate variability (HRV) so you know when you are sick, because you shouldn’t trust your own feelings.


I’m reminded of a bike ride from about four weeks ago. The pace was easy, the cadence was relaxed, yet my heart rate was over 130 beats per minute. That’s what my trusty Garmin® sport watch told me. Because that’s what the watch said, I accepted the number as an accurate representation of heart rate and reduced my bike speed to the point of almost falling over. My HR was supposed to stay below 100. It finally occurred to me that something was not right.

Pulling off the road, I checked the pulse with a finger in the neck and an eye on the digital chronometer. The finger method may not be as convenient as an ANT+ radio signal from a chest strap, but I trust it as being far more accurate. You never know when microscopic electronic components will go bad. By giving myself the finger (three times), I measured a heart rate of 85bpm. And the watch? It still said my heart rate was over 100, way over 100.

Later, I found out that the battery in the chest strap had died and the displayed heart rate was being measured from optical sensors on the back of the watch. Those optical sensors are notoriously inaccurate in my experience.

Can we learn pace without a GPS device? Can we learn cadence without a bike computer? Can we be triathletes without all the numbers? Of course we can.

For some people, it takes years to generate the feel of the moment. I’ve been doing this sport for 14 years and I still have trouble getting into the right run pace without help from the GPS elves. On the other hand, I know what a good catch feels like in the water. At 500 meters into a swim, I can tell if my form is falling apart and I can tell if it’s from fatigue or daydreaming. These are good things to know.

Having a good feel for the sport only comes from experience, loads of experience.

The Power of Numbers

I can think of two very good reasons to train by the numbers:

  1. Accuracy. Certain factors, highly correlated to sport performance, go unnoticed by our natural senses. Any athlete can set their training level by monitoring their own perceived exertion (commonly called Relative Perceived Exertion on a scale of one to ten). But how accurate is that from one day to the next? On Monday you may feel great and have a great workout. On Thursday your mind might be preoccupied with something that makes the training feel more difficult than usual regardless of how hard the body was actually stressed in training. Often it takes objective measures to cut through the noise of our perceptions so we can more accurately estimate what we want. In fact, it often takes complex statistical models to cut through the noise that bombards our senses every second during a workout in order to build a truly informative picture of our fitness (e.g. TSS score).
  2. Discipline. Old habits die hard. Here’s a scenario that may sound familiar. Your workout for today is an easy 60 minute run. As you start the workout, you feel great, but a little nagging voice in your head says, “You’re uh, going kinda slow dontchya think? You’d better pick up that pace if you want to actually train for that upcoming race.” And before 30 minutes into the run, the pace is much closer to race pace than what the workout called for. This is where the numbers come in handy. A good heart rate, pace or power monitor can warn you when you are getting off track from your intended workout plan.

This is your captain speaking…

I’m not an airline pilot. Neither am I an air traffic controller. So if the upcoming analogy is way off, you know why.

Balancing numbers and feel is like flying a commercial jet liner. The captain has to know the numbers. No matter how automated the system, the captain must be able to interpret the numbers, process them and take action. Sometimes, those numbers come from air traffic control: altitude, direction, speed, etc. Other times those numbers come from the instruments in the cockpit: fuel levels, hydraulic pressure, passenger weight distribution. Numbers, however, are not enough. Imagine this:

Good morning, Ladies and Gentlemen. This is your captain speaking. I just want you to know that you are in very capable hands. Out of 100 students I was top in my class for interpreting flight data. We are going to have a lot of fun today, because this is the first time I’ve ever been in a real cockpit…

Hopefully the cabin door hasn’t already been locked by then.

Remember Sully, the pilot who landed a plane full of passengers in the Hudson River? I’m pretty sure he would be the first to tell you that there’s a point where the numbers are good, but your intuition and feel are vital.

Until next time…

References   [ + ]

1. Savell, J. and Gehring, K. 2019. Meat Perspectives: Explaining soft bellies and testing firmness. Meat + Poultry.

A Power Meter Taught Me Something I Didn’t Expect

I have a confession of road rage. Actually, it’s not so much road rage as much as it is road perspective. Would people drive big vehicles at high speeds if they intrinsically knew how much energy those vehicles consume?

This post is about finding that place where we as humans can appreciate what it takes to move through space/time at superhuman velocities.

Car Versus Human

I may be a triathlete, but I’m not just talking about swimming, biking and running. Imagine yourself driving down a highway in your favorite car. Chances are your car is powered by multiple pistons being forced into motion by well controlled explosions inside of a metal block that weighs a few hundred pounds. Now imagine trying to carry your car on your back as you walk the short distance from the parking lot to the chiropractor’s office. I don’t know how many people can do that, but the percentage of people on earth who can would probably fill this page with zeros (either I’m exaggerating or using a large font).

Yet this engine, with its controlled explosions, can move you, your family, some cargo, and those long forgotten McDonald’s french fries under the seat down the highway at 70+ miles per hour for thousands of miles before tune ups and oil changes. I, on the other hand, can run a five mile loop at a tenth of the speed which then requires a recovery drink and hot shower. This perspective alone might make me appreciate how hard the car works to drive me twenty five minutes to Wilmington just so I can run five miles for forty something minutes. And in my 40 minutes of running I put out less “work” than my car did to get me there.

New Perspective

So, when I see someone behind the wheel of a speeding vehicle, I think to myself,

“How many of you truly have an appreciation for the amount of energy it takes to move your vehicle down the road at whatever breakneck speed you can get away with?”

The question may be rhetorical, but it has serious implications for all of us humans who want more and want it now. I have no data to back up this claim, but I believe that if more people had a feel for just how much energy is required to start their cars, they would likely do more walking, running and/or cycling. I once knew a guy who lived on a remote cattle ranch in New Mexico. He would run several miles to his mailbox at the main road. I’ve also known people who would drive less than a mile on a beautiful day to the post office and then sit around the house because they had nothing to do.

The real eye-opener for me was the power meter on my bike. When I first got the power meter, I could hold about 200 watts pedaling for an hour. I thought that was pretty good because I imagined lighting two 100 watt incandescent light bulbs. But my curiosity got the best of me and I wanted to know how I compared to my car, a 2007 Toyota Yaris.

According to Wikipedia, Vincent can generate up to 89 horsepower. (Yes ,I named my car). In reality, it’s probably only using a portion of that. Let’s assume 50% (45hp). Forty five horsepower is equal to roughly 33,500 watts. Vincent, one of the smallest street legal cars in the U.S., weighs only 13 times my own weight but puts out over 167 times the energy that I do and he can do it for much longer. He can produce over seven watts per kilogram all day long. And that is on the low end. In the cycling world, you would be a top level professional cyclist if you could hold that kind of power to weight ratio for all of five minutes 1) “How much better are pro cyclists?”. Cyclist. .

How many drivers truly have that appreciation? I’m sure most endurance athletes do, because they feel the pain in their legs from pushing 300 watts earlier that day. Ever since I started training for triathlon, I’ve been much nicer to my vehicles. I get the oil changed on time (almost on time). I know my mechanic on a first name basis (Nick, in case you are wondering). I also, drive more respectfully of others. Perhaps the biggest impact from this insight is that I value efficiency over speed and style (regarding my vehicles).

Final Word(s)

I don’t want to give the impression that I negatively judge anyone simply because they drive a large vehicle at 79mph on Interstate 40. I myself own a big truck/lory that I use to haul cargo and horses. The U.S. has cheap fuel, wide roads and a car culture built in to the social fabric. There are neither economic nor social incentives to drive efficient vehicles.

The point of my rambling in this post is that, because of my triathlon experiences, I have a feel for how much energy it takes to move, and because of that insight, I live my life just a little bit differently than I used to.

Until next time…

References   [ + ]

1. “How much better are pro cyclists?”. Cyclist.

Congratulations, Chris Nikic!

IRONMAN® Florida 2020 will go down in triathlon history as being the first IRONMAN® branded event to witness a finisher with Down Syndrome.

Against the odds of common societal belief, Chris Nikic did it. His 1% vision is truly inspiring and, in my opinion, will lead to a new way of thinking about reaching goals. I say this, not because you might think he is any more challenged than anyone else. I say this because most of us want 100% change immediately and we struggle with what we actually get in return. Chris’ view is spot on with the reality of endurance: it takes time to develop the skills necessary for long course racing.

Learn more about Chris from his website. And while you’re there, buy a T-shirt. I did!

Chris Nikic’s Website

Until next time…