Functional Threshold power?
- Thread starter ko tko
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It's basically the power you can sustain for approximately an hour under ideal conditions which include sufficient rest and motivation.ko tko said:
It's an alternative to the many definitions of "Threshold" based on underlying physiological processes such as LT1, LT2, OBLA, MLSS, etc. It doesn't require blood lactate testing or a metabolic cart, it just requires sufficient motivation, a well picked day, a good riding venue and a power meter. That's the "Functional" part of it, it's simply what you can do regardless of the underlying physiology so rider's don't have to get sidetracked into 4 mmol levels or 1 mmol above baseline or inflection point, etc. .... It's just the power you can sustain for long periods under ideal conditions and that more closely tracks cyling fitness than what your blood chemistry is doing.
It's a good measure of sustainable metabolic power which as you suggest is primarily through aerobic processes. It also replaces the dated and innaccurate term "anaerobic threshold" there just isn't a point where the body converts from aerobic to anaerobic processes. Even in long steady efforts there's a contribution from anaerobic processes and even in really short efforts like the kilo TT on the track aerobic metabolism plays a substantial role.
The near hour definition for FTP reduces the influence of a particular rider's Anaerobic Work Capacity which can vary quite a bit between riders. IOW, you could track sustainable metabolic fitness based on your best 8 or 10 minute power (and some folks do) but that number can vary quite a bit depending on your anaerobic contributions.
So Functional Threshold Power or FTP is a measure of sustainable metabolic fitness and a good predictor of cycling success in events longer than a couple of minutes. It's also the anchor point for Andy Coggan's power based training levels. But other folks key their power based training schemas to 20 minute power, 30 minute power or even MAP which is closer to best 3 to 4 minute power. FTP has just gained wider acceptance than most of those approaches but in the end is just another reference point.
Another often overlooked point is that FTP effects not just your ability to sustain a high power, but also your ability to recover from frequent hard jumps and your endurance for events ridden below FTP. Even if you do hard jumps and sprints, say in a points race or crit, where the hard efforts are primarily anaerobic and well above your FTP your recovery processes are aerobic. Your ability to recover from frequent anaerobic efforts is determined by your sustainable metabolic fitness or IOW by your FTP. So if you can handle the jumps for the first half of a crit and the same jumps saw you off in the later laps it's very likely your FTP is the culprit and more hard short jumps in training may not be the best way to solve the problem.
Similarly if your FTP is say 200 watts and you ride a century ride and need to sustain 175 watts to stay with your friends you'll be burning through your limited glycogen stores rapidly and riding very close to your best one hour power for five or more hours. You'll almost certainly fade late in the ride and have trouble hanging with the pace. Train your FTP and bring it up to 250 watts and that same 175 watt pace is much more comfortable, you'll preserve more glycogen and you'll last much longer. It's just a lot easier to ride a long ride at 70% of FTP rather than 87%. Sure you'll also have a bit more power for hard climbs and headwind sections and won't have to exceed FTP as often during the ride but you'll also extend your endurance by riding a more sustainable pace relative to your FTP.
What FTP isn't is your one hour "on demand" power that you should be able to generate any day of the week when you feel like it. It represents your best effort under ideal conditions which makes it more conceptual than guaranteed. All it takes is a bit of lost focus, insufficient recovery from previous work or poor pacing and most folks won't hit their FTP for a full hour on any given day.
FTP isn't a guarantee of racing success in a given category either. You still have to race well and have the short term explosive power when you need it if the event demands it. For pure timed events FTP expressed in watts/kg or watts/CdA along with pre-event peaking, pacing and motivation are key but for mass start events I like to think of FTP as your ticket to entry. Without enough relative to your competition it'll take a miracle to stand on the podium but even if your metabolic fitness is on par with the competition you've still got to race well and have the right high end systems tuned up to attack, chase, bridge and sprint as the event demands. And if you've got all that working but don't race tactically you can still get schooled by cagier riders.
So yeah, FTP is a measure of aerobic or metabolic fitness and a good measure of cycling fitness but of course it doesn't tell the whole story....
-Dave
ko tko said:
there is NO power you can ride at without "going to anearobic system"... even when you are asleep in your bed you are using both aerobic and anaerobic systems.. it's just a matter of degree... LT doesn't exist it's a myth.
FTP is simply the power you can sustain for 1hr when well rested and motivated.. many use it as an indicator of their aerobic fitness.
FTP can be expressed as the raw power number or can be expressed as W/kg, which very roughly lets you compare between athletes. W/kg is more accurate for climbing than for flatland riding.. flatland is more about power to CdA (frontal area and how slippery you can make your shape)... roughly/varies as, but not necessarily well predicted by weight... i.e. how flexible/tucked can i get? do i have the shoulders of a girl or like Arnold.. you can see that two riders of the same weight can have different speeds at the same power depending on their body shape and position they can get into...
Wow Dave, that was simply a brilliant answer to the OP's question. If it was attached it to Bill Blacks quote about one of the main objectives of a competitive Road Racer should be to get your fitness up to level 3 so you have enough rope to make attacks and then recover it would be perfection 
Lot's of different training philosophies out there and each will suggest a different way to improve your fitness and your FTP. Personally I go with Lydiard/Coggan style Sweet Spot Training to build FTP. Search SST here and on the net in general and you'll get lots of hits. But the basic philosophy is to do a lot of long sustained efforts that make you work hard, but not so hard that you have to quit early or take a lot of rest days to recover before doing it again.ko tko said:
As for what constitutes "good" FTP numbers, this is definitely a case of "bigger is better" but here's at least one reference: http://home.trainingpeaks.com/articles/cycling/power-profiling.aspx
For that matter, there's a wealth of good information on these pages: http://home.trainingpeaks.com/power411.aspx
And a great primer on Lydiard style SST training applied to cycling by Charles Howe here: http://velodynamics2.webs.com/rcgtp1.pdf
-Dave
agreeddoctorSpoc said:
for what it's worth, I have seen this terminology quite often. In most cases, people that use it actually mean power at VO2Max.
In such a case, aerobic refers to the fact that the component being tested is actually the maximal rate of aerobic metabolism.
Similar terminology that we frequently see is MAP (which I believe stands for maximal aerobic power).
As far as switching from aerobic to anaerobic metabolism, often there's the word "mostly" that is implicit to this terminology. An effort is often said to be aerobic while we should actually read mostly aerobic. In the same line of thoughts, an maximal effort lasting 1 minute can be considered anaerobic (read mostly anaerobic). One that lasts 3 minutes is aerobic (read mostly aerobic) etc...
