Functional Threshold
Someone asked on my Twitter feed today what ‘FTP’ is. I had recently mentioned it in a tweet. Since I use that term a lot it’s probably a good idea to define it. A little background first…
Anaerobic threshold. Lactate threshold. Ventilatory threshold. These are terms used to describe points in the intensity spectrum when the athlete is on the verge of or is already accumulating lactate and hydrogen ions in the body’s fluids. This means that the body is rapidly becoming acidic. Scientists attempt to define the above terms very precisely and see each as having unique conditions. Despite their best efforts even they fail to be in complete agreement on what each means.
As athletes we seldom get involved in such discussions. We tend to see these terms as interchangeable and meaning roughly the same thing – you are “redlining.” And for all intents and purposes, that is reasonable since these thresholds occur at roughly the same point and are seldom exactly the same from one day to the next due to variations in fitness and fatigue.
Magazines and books written for the athletic market use these terms when talking about training for endurance sports, also often interchangeably. So we have come to accept and generally understand what they mean, especially 'anaerobic' and 'lactate' threshold. They are less clear on 'ventilatory' threshold since this term is used much less frequently than the other two. In fact, you can simply use the word 'threshold' when speaking with other athletes and they will usually take that to mean a high effort with an RPE of about 7 or 8 on a 10 scale.
Now there is a new term being used to describe this level of intensity – 'functional' threshold. This is largely due to the work of Andrew Coggan, PhD, and Hunter Allen and their book, Training and Racing with a Power Meter (VeloPress, 2006). I like this term for field work because it removes all of the mystery associated with scientific concepts such as hydrogen build up, lactic acid, lactate, aerobic, anaerobic, RER, ventilatory rates, and the like. Very few really understand these terms. Functional threshold solves this problem by defining redlining based on actual output in a field test or race.
Functional threshold power or pace (FTP) is the highest mean average power or pace you can maintain for one hour. That’s quite precise, clear and logical. It even fits nicely with what we know about AT, LT, and VT. When you are in good shape these various measures of intensity can be maintained for about an hour. So rather than trying to describe this phenomenon with biological conditions, we simply define it based on a common output denominator.
Once you know FTP your training zones may be established based on power or pace. WKO+ software does this for you. All you do is plug in your FT power (cycling) or pace (running) and the zones are automatically calculated. Then workout intensity is determined based on pace or power zones. WKO+ will also determine heart rate zones using the system described in my books. Just enter your average heart rate for a one-hour race effort. Of course, this software goes well beyond simply setting zones. It also allows you to see a visual representation of the pace- or power-based workout and graph the workout/race data into several different charts for analysis.
All of this analysis data is based on FTP so it must be kept updated with periodic testing to make sure you have it right. Over the course of a season FTP will change a lot if your training is affective. And it is one of the best indicators of how your fitness and race readiness are progressing. While heart rate remains rather steady throughout the season, power and pace change considerably. That’s obvious since becoming more fit provides several benefits including being faster and more powerful. Training is all about accomplishing these goals. That’s why I keep a close watch on FTP for the athletes I coach and highly recommend that self-coached athletes do the same.
Labels: ftp, functional threshold, pace, power
posted by Joe Friel @ 6:48 AM
15 Comments
15 Comments:
I appreciate your posts on Twitter. Very informative!
This is a great explanation of all the "threshholds" we hear and how confused most people are with them. I think FTP is by far the best for being easy to understand and easy to measure. Thank you for sharing this!
I will definitely explain FTP to others when they're talking about threshhold.
@JaredDetroit
If you average heart rate goes up between FT tests, such as the 30 min TT recommended in "Going Long", are you getting fitter or not? Taking into account that you managed to go 1 mile further the second time. Confused Steve
Ive read a lot of your blogs and find them extremely helpful but I was wondering what you can do to figure out your functional threshold without a power meter. I've looked into getting a power meter and just can't justify purchasing one based on the amount of training I do on the bike, but would like to use something a little more accurate than HR for FTP. Should I use pace or perceived exertion or something else?
Joe: Do you find that as an athlete improves or weakens his power changes at FT but his threshold doesn't? i. e. I'm at peak successful training and my power is 300 watts at threshold but through the thanksgiving couch potato stage my watts at threshold drop to 225 watts. But: --both are at 154 bpm threshold or my 1 hour functional threshold power average HR.
Glenn
Anon--I'm sure you can answer your question yourself with a little prompting. What if HR went up but power (or pace) got worse. Would a higher HR mean you were in better shape then? What this tells you is that HR only means something if compared with something else. HR by itself is notindicative of anything (except for indicating you are alive).
I run...--Speed on the road is close to meaningless due to wind. One way to greatly reduce the wind effect is to do a TT on a steep hill. Time would tell you how you are progressing. But this information would not be helpful in your training and you couldn't transfer it to training anywhere else. Look into the Polar power meter as a less expensive option.
Glenn--This tells you exactly what you want to know: Fitness changes are measured by output (power), not input (HR). Regardless of HR your power is dropping as you lose fitness. A power to HR ratio is a great way of putting a number on this. Divide your FTP by your LTHR at various points in the season and you are expressing your fitness in a single number.
Joe - What test can I do to determine my Running (and swimming, if possible ) FTP? I have a power meter, know it and use it for cycling and would like to do so for running and swimming.
As a runner is Functional Threshold Pace for running accurate? What if there is wind, different terrain, or changes in elevation? Pace doesn't account for these in in a FT pace test. I know distance running doesn't have a power meter yet, but how good is Fuctional Threshold Pace if it can't account for some of these variables?
Anon--I generally use a 30 minute run time trial (solo, not race) and a 1000m swim time trial for FTP in those sports.
Shane84--Pace is considerably less accurate than power, for all the reasons you mentioned. One nice feature of WKO+ for pace is that since the device knows altitude the software can normalize for grade ('Normalized Graded Pace' - NGP). It still does not know how to normalize for wind and surface (sand vs asphalt, for ex). If you do the FTP test on a track you eliminate hills and surface as an issue and wind, if it is only slight, is also mostly cancelled. Of course, once you have run FTP being able to use it in training is another mattter since there aren't any devices now that offer real-time NGP. Some day there will be a power meter for runners and then run training will become much more precise.
Joe
If the blood becomes more acidic at LT levels, would you be able to counter this with alkaline foods? Say raisins..? Or would the body accumulate acid too quickly for the gut to process the foods?
Sam--Blood acidity due to intense exercise is short terms, as in seconds. Eating alkaline foods is a much longer process. However, there is considerable research showing that pre-loading with sodium bicarbonate (baking soda) reduces acidity during very short, very intense events lasting less than 2 minutes, such as an 800m race.
Joe: Interesting comment about eating alkaline foods or taking a anti acid like baking soda shortly before an intense race. I wonder if that would work if say you were on a long endurance ride but suddenly needed to "take into the red". Take an antacid to knock out some of the buildup in your legs from the >LTHR time and therefore extending your time to fatigue? Interesting. I'll pack a few of those powder antacids on my next ride and test it out. Thanks. Glenn
Hi Glenn--It's been a while since I read those baking soda studies, but I believe they went through a loading period before the test. Don't know if that would work in a race as you suggest.
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